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Your a bit off Many modern engines actually have a high end low octane table you will switch between one and the other if the knock sensor sees knock if it continues to see knock once it switches to the low octane tit able for the Ignition timing it will then go in the limb mode. My BMW is a classic example of this. This was even shown back in the 1980s on forge Thunderbird Turbo coops where they actually had a premium and regular switch on the - and it would control 2 different spark tables.
"higher octane does not give you better performance" is totally wrong and misleading. There are plenty of cars (from Mazda, VW, BMW etc.) which come from the factory with different power ratings for different octane fuel (lower power with lower octane, higher power with higher octane). If you've ever tuned a turbo engine you'll know all about engine maps dsigned for a specific octane fuel or ethanol blends. Higher octane (or e-blends) allow for more advance timing, which in turn equals more performance. ..so "myth" NOT busted, until you can get BMW or VW to write a retraction :)
Omg I’ve never been so wrong in my life. I always tough + octane = more knock xD !!! Question: do octane number degrade in time? Like, if I put 98 octane and leave the car in the garage for 3 months does it become say 97 or 96?
You should have touched on the etanol levels in the diffrent kindes of fuels. In Sweden we have 10% in our 95 and 5% in our 98. Or make a dedicated video because EU has set a minimum of 10% etanol and this raises a lot of interesting questions. Especially for older engines. Keep up the good work
ethanol is a modern aditive to prevent detonation on gasoline since lead aditives were banned. the downside is that ethanol can corrode aluminium parts and react with some kind of rubber used on old engines. in a nutshell you could say adding ethanol to gasoline is a way to increase the octane rate. Brazil has 25% ethanol mixed in the gasoline. You can buy regular, additive (with more detergents) or premium (95-99 octane but usually ethanol free).
The question is how bad 10% etanol is for an older engine not designed with etanol in mind. Like you say rubber gaskets and such. I pay a little premium and fill up with 98RON 5% etanol on my old outboard engine. All other gas is at least 10% here.
Should also be noted that ethanol will break down faster than pure gasoline, so if you are filing a infrequently used engine (lawnmower, boat, generator, etc.) Or if you are storing a reserve of fuel in a gas can it would be a good idea to spend the extra couple of bucks on ethanol free premium fuel.
still the best automotive youtube channel in my opinion! Best possible explanation you can find in the whole internet I think. Perfectly presented, clear speech, exceptional technical knowledge, paired with a healthy amount of humor, an no bragging, and no nonsense or myths sponsored by God knows whom! Wonderfull my friend, love every single video you made so far! keep it on! Greetings from Austria!
Those impressions, especially that American accent were far from clear speech... I have no idea what he was on about! But the rest of the video was very clear :)
This explains the difference between Europe and US octane numbers really nicely. I was surprised that Audis require 95 octane, but it makes sense that it actually means 91 in the states
@@izgrevski056premium in alot of the US is 93. In my State it's 92. It's 91 in California for example, it can vary by state. Some stations in the US have 110 on the pump, E85 etc.
generally the fuel is the same. Its just a different measuring system. Though some engines can advance the ignition timing with higher octane fuel than what theyre rated for which increases power and/or fuel economy. Most modern engines can retard the ignition timing with lower octane fuel than what theyre rated for in order to prevent engine damage. General rule is: Whatever it says in your car manual which fuel to put in is the fuel to put in.
Does not explain why my old '88 LSC got 15 MPG in California and 19MPG in Texas. Both are 93 octane as required in the owners manual. Could be the TEXAS blend had less alcohol mixed in? Say 10% less ? No I did not change the timing. BTW I went from a refinery job in CA to refinery job in CA. The difference between fuel stops is noticeable. If you use cash.
@@warrenpuckett4203 could be all sorts of stuff. Maybe very different altitude maybe more Ethanol content as you said or maybe you just drove differently. Like maybe you had a lot more City traffic at one Place but im just guessing. Also im no expert.
Great video! i got tired of explaining to friends just what you said in the video. Another misconception i hear a lot is about ethanol making more power than gasoline Ethanol actually has a lower energy content than gasoline, so if all things are equal, it either makes less power, or takes more fuel to make the same power What actually makes more power is the higher Timing/Compression ratio/boost that ethanol allows you to run in relation to gasoline.
If a vehicle has the capability from the factory to run e85 it is possible to make more power than gasoline without any other modifications. The reason is that the spark table will change based on conditions and input from knock sensors. Less knock and colder combustion means more spark advance
@@Carlos.Rivera because, like i said, ethanol has a lower energy content, to make the same power, you must run a richer A/F ratio, you are always using more fuel to move the vehicle irregardless of the power it makes in relation to gasoline.
@@jamesd2863 yeah, that's why i mentioned timing. In Brazil most cars are flexfuel, and make around 3-5 more HP when running E100 than gasoline (actually E27, not pure gas)
E85 fuel for example has an approximate octane rating of something like 114 and also has colling effects. Ergo you can generally run more timing and boost with E85 fuel than standard gasoline. Even though you will be using more volume of fuel, at the price and availability at many pumps it can give you comparable performance to race gas and cost less and be easier to get.
For inferior fuel, in rural Mexico cheaper 80 octane fuel used to be common. However, low compression engines with the timing retarded would run fine on it. Which is why the air cooled VW's and older American cars were popular as both had low compression engines...
Some manufacturers have played around with variable compression engines, and we may see more of that as emissions and economy standards tighten. For now, a similar effect can be achieved with variable valve timing being able to transition from Otto cycle to something like a Miller or Atkinson cycle.
Even though the Europe octane number is higher for the same fuel than in US, based on the video if eu 95 = 91 in us, we got higher octane fuel here. The thing is that you cannot buy anything less than 95 here in EU, but in US you got 87 which would be like a 90 in EU (according the the table in the video).
@@Bamsebrakar2011 Not so sure about that. In central europe for example you can find "91" on some fuel stations price thingy and a nozzle for it, but it costs the same as 95, as it is actually 95. It's mostly older fuel stations that have not yet been renovated and the 91 labeled parts removed or relabeled. The raffineries here (like the ones from OMV for example) don't even make anything less than 95 anymore. (Hence the same price for "91" and 95 on the few stations that still have labelled "91")
Great video! I can't even count the number of times I've seen people say they use higher octane fuel "because it contains more energy" on a low-compression engine!🕵♂
I worked as a fuels chemist for years. This is a good and simple explanation of octane number and thankfully does touch on the R versus (R+M)/2 methods for certifying knock performance. This is what misleads Europeans into thinking that their fuels might be "better". In reality, the American specification is harder to meet due to averaging motor octane into the rating, where the "M" is the anti-knock performance under load. Also, octane rating is only one data point among many in certifying a finished fuel. I recommend comparing ASTM D-4814 to whatever the equivalent European standard is for a more comprehensive comparison.
Apparently many tuned cars imported from Japan blows up when American fuel is used. So there seems to be some differences in fuel quality between countries.
@@cossiedrifter also, every one of those cars are 20-25 years old with 30k miles. Nobody wants to open, clean and re-seal before restarting and it just dies.
@@nagyandras8857 far from it buddy get your facts straight your guys regular is on par and the same as our regular, remember we all get our gasoline from the same place it’s just rated differently
Always the best automotive channel with clear and precise explanations, but acting? I was not expecting that! This is as good as the greeeeen screen shenanigans. Congrats and once again, thanks for the video.🏆
Aren’t many of the new engines adjusting ignition timing depending on fuel? I remember hearing different power figures stated by manufacturers for "regular" vs. "premium".
Only if the engine is supposed to run on premium. Running such engines on regular can cause pre-ignition which will cause the knock sensor to send a signal to the computer to retard the timing, which will result in a loss of power. It could also possibly lead to engine damage. Use a fuel with the level of octane recommended in the owner's manual for the vehicle. Nothing more, and nothing less.
@@dancancade7101 nothing beats when poor fools put gas in a diesel engine Note got a cam am spyder recommend fuel is 97 USA so am left with using 93 all the time
@@dancancade7101 That's not necessarily the case anymore. Various manufacturers will say you will get peak power running premium, say 91 octane, but the car is still able to run 87 octane safely.
@@chickenfishhybrid44 if "peak power" is obtained by the use of a higher octane fuel, then that’s what the engine was designed for. Either the engine has higher compression or it's supercharged/turbocharged and the use of a fuel with lower octane will result in the computer adjusting according. What's the point of buying such a vehicle if the plan is to run it on low octane and never get the level of performance that you paid for?
I can't get anything lower grade than 95 RON in Switzerland, while regular in the US is ~90 RON. I tend to use 98 octane in my motorcycles (95 octane contains up to 10% ethanol which is an issue for my models) and in my "other" car which specifically requires 98.
In the US, it varies by region. In most of Texas, you would get 92 RON equivalent, somewhere like California will be lower, and Northern New Mexico starts at 88 RON equivalent.
While true for driving to the supermarket or normal commutes, I would add that there are exceptions to the more octane than recommended does no good rule. In extreme applications where heat build up in the engine is expected, a slightly higher octane than recommended can help. Example: towing with a gas v8. Most trucks in the US require regular gas, but premium can help eliminate knock in a heat soaked engine, helping with power and fuel economy. See also rock crawling, and drag racing. In drag racing a turbo 4cyl that required premium (93 r+m/2), I've had good results with mixing in no lead 100 r+m/2 to bring the average up as high as 95. Go beyond that the specific vehicle's requirement to keep knock in check in the specific application, and performance will begin to decrease. Also helpful on long climbs in high altitude mountains where the thin air reduces cooling.
At altitude, I believe you need less octane. That’s why you see 85 in Denver. I get why you may opt differently in a fully loaded older engine that may have hot spots though.
@@Thatdavemarsh My specific experience with mixing 100 no lead from a VP station was low mileage high compression NA motor with direct injection that required premium fuel. I initially purchased the 2013 BRZ in Denver, and performance was deplorable. A VP station in Albuquerque NM with 4 gal of 100 R+M/2, and filling up at every 1/2 tank provided a record MPG on a trip from there to SLC, UT. 40-50% better than the trip to ABQ. I could feel the car reducing power after every fill. The performance was completely unexpected. The VP fuel was over $5 a gallon, which was insane at the time. It was about the same as the other 7+ gal of premium I put in at the same station. I still saved money over the entire trip because of it. If only I could get it for that now. I believe the octane ratings at high altitude are specifically for old engines. The distribution model was set up during the age of carburetors and distributors. Modern engine management can take advantage of the better fuels.
*petrol -petroleum, liquid Gas, LPG, is a gas. America needs to really get on board with not being the only country to do something differently for no reason, especially as it's stupid.
Excellent! You'd fit into the mid western state seamlessly, man! 🤣 Some 25 years ago, I was working at an airfield. One day a jerrycan with some 10 litres of Avgas, 150 octane aviation fuel, was left over. As my Volvo 244 had no catalyst yet, I was the lucky one to win free fuel that day, yay! 🤗 There was about 15 litres of 95 octane in the tank left when I poured in the Avgas. I had never before heard my trusty old Volvo run _this_ smooth. Like a V12, like a turbine! That being said, the B21E engine was a rather gentle character to begin with. That was a very very lovely car indeed!
The engine's ignition timing was wrong , there was a cooling system problem or the cylinders had severe carbon deposits,if what you say is true. They are the only diagnoses that can be deduced from what you describe.
@@paulg3336 Nope, the engine was enjoying best health. Back then I didn't have the knowledge to check such things myself, there was a retired mechanic living next door to did such jobs for small money. Brilliant lad, he knew 100% what he was doing. As I didn´t speed with my 244, I did obviously not have a chance to notice any performance differences, but I did notice that the engine sound changed and the bugger felt more gentle in general until I put fresh 95 into the tank the next time.
One of the cars I have driven specifies a minimum of 87 (R+M/2), but can go up to 93 as stated in the user manual. It delivers best performance at the higher octane ratings, since it can advance the timing before knock occurs and uses the knock sensor to bring the timing back if 87 is in the tank. So while it is mapped for and can take 87 octane, it does benefit from a higher octane gasoline in the tank. I think this is great since if you're on a highway trip you can fill up using cheaper 87, but if you want to do any performance driving you can still get the maximum out of a higher octane like 93.
Regarding compression ratio: is the swept volume into the minimum volume. Using a domed piston decreases the minimum cylinder volume while maintaining the same swept volume, hence a higher CR.
in in college i had a combustion class and we had a big calobrated octane tester. gotta know that the difference between stations was more then the difference between the octane levels at the pump. ever since it leaves the refinery its continues to change octane as stuff gasses off. the cheapest gas did the best, probably because more people buy it and gets more turnover and has consistently fresher stuff. they also did the best for the lowest water content for the same reason. it was like valero that was above shell, chevron and the like. I've never had problems with ethanol in my old cars but maybe its because I get the cheap stuff that's dryer.
ethanol absorbs water while gas does not, so it does provide some protection if water is an issue in your fuel. the issue with using it in older cars are the rubber components can get eaten away over time, its not going to effect the running of the engine. I've pulled the injectors from my jetta with 120k kms and the seals were in better condition than a car with only 40k, I only run 94 which up here in canada is required to not have ethanol.
@@Born_Stellar gas obsorbs water too all the time but in large gas storage tanks the ethonal drops out into the water sitting on the bottom. and when the water is drained away along goes the ethonol. and because ethonol is the primary octane booster now the gas has a lower octane.
@@xidarian the gum is the oil additives the put In all gas. If you leave your peacock on and the bowls are continuly full and evaporating off what's left behind is the oil additives. it will gum just as quickly with non ethanol fuel as ethanol fuel. It reely doesn't do that mutch but people will blame all their woes on ethonol.
Australian 91 has 150ppm sulphur making it dirtier out the exhaust on top of being lower Octane. Definitely seen better economy with higher octane fuels on modern motors, like the timing increases once it works out it's not knocking.
It actually does lead to better performance in turbo engines, they usually are recommended to run on 98 ron/93 aki and thats where they have their advertised power output in older turbo cars, but they still can run on on 95 ron/aki just fine, justbthat it will be will slightly pulled timing hence lower performance. Naturally aspirated engines CAN benefit from higher octane with engine mapping tuning and more aggressive ignition timing on 98 ron. So its not like there is no gains to be had from running higher octane, but it requires extra steps to be taken to actualy experience those with na motors.
The UK situation is confusing because the government has created a link between octane rating and ethanol content. 95 RON petrol is E10 now but the 97-100 RON fuels are allowed to stay as E5. As E10 (in theory) has 10% ethanol, it has lower energy content than E5, so in this case the higher octane fuel does contain more energy, but not because of its octane rating. In practice, E10 only legally means "up to 10% ethanol" and some batches turn out to have no ethanol in them at all.
Higher octane fuel allows you to add a bit of spark advance. The actual amount of power gained is always less than about 5% in ideal situations, and typically it is negligible. If your car knocks on acceleration then use premium. If it doesn't then don't put it in; In any case follow the manufacturer's instructions.
This is the reason why whenever possible, I try and run nearly dry the tank on my jeep and fill with 93 (US) before towing near max capacity for long distances. It doesn't allow the engine to make more power, but it does keep it making max power when pushing the engine harder, which also means I actually get a (1-2 MPG measured) increase in fuel economy on those long distance towing trips. I've made the same trip with the same load multiple times (track day towing) so I was able to verify.
Al si skinuo Amere,svaka cast ! :D Oplakah Imam auto iz 2001god. i drago mi je sto sam pogledao ovaj video,ustedeo si mi novaca, hvala! :) Bome si detaljan u objasnjavanju, svaka cast!
Some manufacturers (like Ford) will rate a car for 87, and rely on knock retard to keep it alive. The 3.5L V6 Ecoboost is a prime example of an engine that gets substantially better fuel mileage and torque output by running 93+ in the 87 rated car. You'd never catch me running 87 in a GTDI engine, regardless of what the manufacturer states. All of these claims I've made have been verified by thousands of ecoboost owners with aftermarket tuners and dataloggeers. It's pulling timing all over the place on 87. Get the OAR (Octane Adjust Ratio) above .95 and they come alive on the stock calibration. According to Andre at HP Academy, the Subaru platform also have an aggressive timing strategy that lives on knock retard, but on any pump fuel lol.
I had a Ford Focus ST 2.3 Ecoboost, which was rated at RON 95 (91 octane in the US). I think RON 98 was just better and so that was always my choice (or better!), but once I made a test: Run with RON 95 (91 octane in the US) and give it some full throttle moments on the Autobahn. OAR was at .77 and the case was clear. Top speed died at 255 - way below the possible maximum - and it was thirsty, too. Later on there was another test: This engines works totally fine with E10 (RON 95 with 10 % ethanol), but you may not push that engine too hard. If you push it, you'll better have a higher octane fuel.
I've seen differences even on the 3.7 NA V6. Rated @ 306hp in Mustang spec, some dyno pulls have shown 12-18 hp increase just switching to U.S. pump 93.
@@michaelallen2501 but if you decrease boost and retard the timing you leave effeciency on the table. Ford could have gotten a couple more mpg on EPA and then wrote something like you can put in regular but premium recommend
Actually most modern engines are programmed to deal with the reduced octane number fuel by reducing throttle (or more diluting the intake air by the recirculated exhaust gas) together with the timing readjustment without going into limp. So when you use lower than recommended octane rating fuel, the car runs without setting any error, but has reduced performance. Then returning back to the recommended fuel rating will "boost" the performance back. With modern turbocharged engines with intercooler the engine performance (torque and power) are electronically restricted anyway (to prevent overload so excessive wear of the other drivetrain components and heat management issues in the engine), so the change with the worse fuel is even not noticeable. Maybe the lower octane fuel does not allow the engine to operate in a more efficient region, so may cause worse mileage, but the price difference uses to eat this benefit away. But all that is relevant only when using worse than recommended fuel (of course assuming it is still permitted by the manufacturer, e.g. as an "emergency use" or so fuel; e.g. Golf V with 77kW 1.6l - the manual explicitely stated the recommended is 95RON for full performance and minimum 91RON with expected reduced power).
While I can't speak on the world as a whole I can safely say that Most places in the world have fuel production extremely well regulated and encountering "Bad gas" is simply not a thing anymore. Back in the 60s and 70s sure but modern day fuel is very consistent. Similar thing with motor oils ironically. The absolute cheapest oils today are better than most of the top tier oils from 30 years ago. In the US fuels are tested regularly and have significant fines for companies that fail.
I enjoyed this. Learned a lot more than engineering school. I had hell owning a euro shop in USA where owners would assume RON numbers fit octane. Havoc ensued.
The compression ratio can indeed change in modern engines. This can be done with variable valve timing, and variable boost pressures in cars with Turbos. These are all compression ratio modifying tool, which is why they get used in the first place.
@@MrTorarp It 100% does. That's literally the whole point of these two devices. A turbo lets you compress more air and fuel into the cylinder, and variable valve timing can change how early or late the valves open, again modifying the volume of air and the rate at which it gets compressed. Engines are compressors. That's all they do.
@@Nabeelco No you're wrong. Compression ratio is defined as the volume of space at bottom dead center versus the small space at top dead center. How much air you put into that space does not change the compression ratio. What you are changing with turbo/super charger is another engine characteristic called "volumetric efficiency".
In our region (Maritimes, Canada), the bottom two grades may contain up to 10% Ethanol, but the 'Premium' grade typically does not. So that's a factor that was not mentioned here. Your regional circumstances may vary. I recall that my 1986 VW GTI supposedly had adaptive spark advance, constantly advancing the ignition timing to just before the point of detonation. So the spark advance was governed by the fuel. Buying the best fuel (Sunoco Gold) made an obvious difference, and No, I wasn't just imagining it. Present vehicle runs 16 psi boost, so I'll take the best gas thanks.
The spark advance on an '86 GTI is good for about 5 hp in ideal situations. So you went from 105 hp to 110 hp; I hardly think that would be noticeable. By the way, by turning your distributor about 5 degrees counterclockwise you can achieve the same thing, but listen for spark knock...
@@Flies2FLL The 86 VW Golf GTI is very light, weighing under a tonne, so bumping power from 105 to 110hp would be noticeable! I've always drive small cars & in some cars I'd notice the power difference when changing the fuel filter or air filter :)
@@jayr6637 Those weighed about 2300 pounds. I drove an '85 Scirocco turbo for 8 years, and one thing I noticed about the car was that a long drive on the interstate highway really made it run good the next day. It felt much "snappier", though I doubt it had any more actual power. A 5% change in power will be barely noticeable, if at all. Trap speeds in a quarter mile will show the improvement.
@@Flies2FLL A buddy of mine had an 86 Golf GTI 3 door. His definitely weighed under a tonne, about 920kg... maybe they weighed more in the US due to regulations. Anyway, maybe it's because I've never owned a car weighing over a tonne & have always owned NA manual cars, but I notice small gains... especially on familiar roads :)
My understanding is that some engines can adjust settings to take advantage of higher octane and produce more power. In 1996 Honda released a 1.6L Civic on the New Zealand 🇳🇿 market which had a budget style fuel injection they called Group Injection. This had only two fuel injectors which I felt at the time was a major step backwards from PGM-FI. However, group injection was also paired with a knock sensing system which Honda claimed could sense and adjust to a different octane rating in every engine cycle - very impressive capability from something that is impossible to achieve in a practical way. In 2000 when 98RON fuel ⛽️ became available in addition to 95RON premium and 91RON regular, Honda NZ claimed a 5% power benefit from 98 in my 1994 Integra VTi-R over 95. I did notice an improvement. Currently I run 100RON in my Mercedes CLK 320 W209 and it goes like a rocket 🚀😀
Interesting video. I was just talking about this in my video on my imported Mercury Grand Marquis which I imported here to Europe. The caveat is that in the US, it’s customary to fill up with the standard 87 octane whereas here in the Netherlands, euro95 is the standard which is the equivalent of 91 in the US. So in my case, I am putting better fuel in it in the context of octane rating.
Unfortunately using higher octane on engines that make no use of higher octane is a waste of money (here where gasoline is cheaper than octane additives) and can actually lead to efficiency problems. Really cool that you decided to import one those though. 👍
There is one thing -- higher octane also often has better additives to help clean the engine and valves (more so with indirect injection). Not always, but often it does. I sometimes grab a higher octane just to pretend and hope it cleans the engine better, and even if I grabbed a full tank (50 litres) it is close either $2 or $4 difference usually. Or some petrol stations offer normal "95 pro" which should have better additives, usually cheaper than 98 but ... your mileage may vary (literally) though :)
This is highly dependent on the brand of gas station. Some put more detergents and other stuff in higher octane fuels, others put the same amount in all octane ratings.
This is certainly not always true. Basic additives are always included in all fuels. Additional additives are added by the station thus if you want more additives, the best way is to buy it yourself and add it to your tank.
I had a 92 Isuzu pickup with a 2.3l two barrel carb. I had a job that required me to drive one hour each way on an open stretch of I-10 4-5 days a week. So I tested all grades of gasoline for 6 months. 87=24mpg, 89=25.5mpg, 93=23mpg. I had to fill up every 2 days. So I tested them all alot. This was also back when all grades were only 10 cents apart, but those are the results everytime
Im wondering whats the highest pump gas you can get in the US? Cause that could be comparible. In Germany for example the highest pump gas Rating you can get is 102 ROM which would be around 97 in the US. But you can actually get it all over Germany. There are a lot of gas stations where this is available.
Vincent Rohrig, greetings, around where I live( Wisconsin U.S.A ) you can get, although it's designed for recreational off road use only, ( I use it in my sportbike when I spend a day on my local racetrack) 98 octane (antiknock index RON+MON divided by 2 ), or just RON( I think around) 103 or 104 ( your system of measurement). This fuel also has 2 extra caviats, 1 It is true GASOLINE, that is it is Not ethanol and does not contain any alcohol, and 2 This fuel contains lead. Leaded fuel was phased out in the United States I think around the early 1990s because of leads high toxicity. Lead was introduced by Dupont corporation I think around 1920, as a means to boost octane ratings of motor fuel, as well as being a lubricant for valves. Also, this fuel can NOT be used in the majority of road vehicles because the lead will in short order destroy a car's catalitic converter. I can use it in my old zx7 ninja safely since the bike has a race pipe on it and is sans catalitic converter. By the way, you are very blessed to live where you do, as a longtime somewhat knowledgeable Motorsports fanatic I realize your general populous are FAR higher skilled drivers than the lacidasical drivers here in the states. Just curious, do you by chance live near a derestricted portion of the Autobahn?, If so how often do you see exotics and hyper cars flying by in the left lane at, oh say 300 k.p.h. or more? That would be a awesome sight! Thanks for sharing. Cheer's!!!!!!
@@Sjef0194517greetings, what kind of racebike do you have, and what tracks do you ride? I have 2 ninjas, a ancient ZX 7, and a zx6r. My home track is road America, Elkhart lake. They just held the Indy car race here last weekend, that track is so beautiful with 3 long straights. Thanks for sharing. Cheers!!!!
@@steveapel2961 Hi Steve I ride the F1 circuit Zandvoort in the Netherlands and the motoGP TT circuit Assen foremost. Both are extremely fun to ride. And the plan for next year is to ride Spa-Francochamps in Belgium as well. I do this on a old 1999 Suzuki GSXR 600 SRAD. and trying tot get under 2 minutes on both tracks (fastest for a bike is 1:52min)
exactly, on high compression ratio engines where you have high timing targets and advance timing you will create more power. That is why when they remap / tune the ECU's other than adding turboboost among many other things, advancing ignition timing is always one of the things they change. More advanced ignition timing = more power. This video is only half-true and doesn't really go in depth with other scenarios.
I’m so glad that you explained this. I can direct my friends who believe that higher octane fuel has more power than lower octane fuel, to your channel.
Look, they are all misunderstood. For example, I drive a 2019 VW GTI, and on the gas lid, it says, unleaded fuel only, 87, 89, 91. Now if I pump 87, the car won't have the same HP to the wheel. The GTI supposedly comes with 226 HP to the wheels, so if I pump 87 I'm not getting 226 to the wheels, if I pump 89, I won't get 226 to the wheels. Now if I pump 91, I will get the full performance of the engine. Now I can pump higher octanes passed 91, and that won't add any HP or have any different effect. My engines max output is 226 on 91, so pumping higher octane won't do a dang thing. This goes with every vehicle.
Well, is it really mythbusted? The highest octane rating available in the US is 93 premium which is basically 97.5 RON in Europe. Yet every European country has 100 RON available.
@@zochpeter "Full of ethanol" - sure, the mandated 5 percent. However, it has a higher ROZ octane rating and such enables certain engines to produce more power. Also, could you please provide a source for your statement with reduced energy content?
interesting thought from an explosives expert here.. when two blast waves collide, they magnify at the point of intersection (known as the mach stem effect) these colliding shock waves are many many times more powerful than either of the initial Shockwave (we induce this effect to get better performance of explosives with less explosive material) this sounds like it is a contributing factor in knock causing cylinder damage
I just wish my southern American accent was that good!! I'm from the southwest US, about 6500 ft above sea level, yet I don't hear anyone complaining about octane numbers! I won't complain about 87-91 octane, because these days, we'll take anything we can get! Diesel shortages are already affecting local businesses. When my turbocharged "racecar" needs gasoline, 91 octane is noticeably better for performance than 87 octane. You couldn't change my mind.
The map on my engine, is designed to work only with 99RON UK fuel. It would be dangerous for me to use any less. And it does make more power on higher RON rating, as proven on a dyno. Decent video, but over simplified to suggest lower octane will give more power, completely wrong and the opposite is true. It's not a waste of money to use higher RON fuel, as proven by 1000's of motorists who get a much better fuel consumption with higher RON, and in fact, save money by paying a little bit higher price for the higher RON fuel, but get more mpg which actually works out cheaper for them overall.
One thing you're missing is that some manufacturers like BMW, Honda, Ferrari to name a few have higher compression ratios (and/or boost), then tune timing and valve control dynamically based on a measurement module. In BMW cars it's known as the ionic sensor, where it uses the ionic content of the combustion cycle as measured by the spark plug electrodes to relay more precise information about knock conditions to the ECU, allowing it to respond to higher octane gasolines, up to the engine's max potential of course where it can operate at optimal timing and valve lift.
That still means (western) Europe has better fuel than the US. Our standard fuel is euro95, which is equivalent to 91 in the US, which is always marketed as premium fuel. I have never seen the equivalent to US regular gasoline, here.
It depends on which state you live in. Where I'm at we have 93 Octane fuel everywhere. But according to his chart, Europe technically has 94 Octane fuel, which in theory is slightly better than what we have here lol
Small price to pay for paying $12 a US Gallon vs current inflated price of $5 a US Gallon. BTW, in Russia it's still .50 per liter ... I don't thing the "Boycotts" are working in our favor ... a question for "Davos" participants n'est pas?
@@craigsowers8456 Thr Russians also have an average wage of a few hundred dollars a month, so to them that .50 per liter still feels like a large purchase. If they spend let’s say $32 per tank 2-4 times per month, that’s a large chunk of their income just on fuel
As other comments are also talk about alcohol level, I keep it short. Alcohol per volume created less heat than pure gasoline and so if in high octane fuel we have less alcohol, therefore per volume it must create more energy. Of course I already accept that I am wrong because you are the GOD of engine Sir.
Yes, the ethanol content definitely plays a part, you're not wrong at all and I'm only human. I avoided speaking about ethanol in the interest of video simplicity and brevity. I'll try to do an ethanol video in the future
The benefit of higher octane is actually beneficial in carburetor vehicles. It allows you to advance your timing a few more degrees for a bit better performance.
"(ron + mon)/2" as octane rating smh. this just goes to show the length america is willing to go to not use standard measurement the rest of the world uses. americans probably think it's edgy but it's actually cringe.
In England we have 95 Ron unleaded that has just had it’s ethanol content increased from 5% to 10%. We also have 98/99 Ron “Super” unleaded with 5% ethanol content. Of course, in the good old days of leaded petrol (that smelt so much nicer!), we also had 101 Ron “5 Star” that was used for performance cars; “4 Star” was more most normal cars and “2 Star” was for economy low powered cars.
Very good imformation I always thought higher octane increases performance, your topics certainly help take away the myth thank you very much, it all comes down to tuning and knowing your compression ratios awesome.
Excellent discussion on octane numbers. Many premium cars actively adjust timing depending on the fuel in the tank, easily perceptible when driving. And yes, using recommended octane gives the best results. But, as noted in other comments, there can be other considerations besides octane when choosing what button to push at the pump - ethanol and additives. Typically, there is less to no ethanol and more additives in premium fuels. Many mechanics swear these are important if you’re going for long engine life. Myth or fact? It would be great if you could weigh in on that.
You’re completely right, however what you are missing is those of us that run older cars and 98 being the only way to get e5 instead of e10, at least in Europe.
I believe you did a good job here. And a lot of good comments here too 👍. I personally use non ox premium in all my small engines, marine and powersports engines and haven't had issues. Ethanol works in vehicles that get used often so the fuel is kept fresh, but can be disastrous for small engines and stuff that is sits for long periods. Because ethanol does degrade fast and also absorbes moisture so it can phase sperate, another bad thing! I have cleaned and repaired a lot of those fuel systems. Also there is less energy in alcohol so it can slightly reduce fuel economy, but the price difference for non ox fuels usually negates that. However I have also seen studies and heard opinions that suggest the use of ethanol has no overall net gain for us all.
Something to be said about engines that have adaptive fuel capabilities, my FRS would 'gain' power up to about 94-96 octane, and derate significantly on regular. Also ethanol content can make a difference in power and fuel economy. All this without throwing codes.
In Brazil since 2020 the method used is RON, our regular gasoline has 93RON and Premium has a minimum of 98RON, but the most sold premiums have 102 and 103RON, our regular gasoline has 27% ethanol and the premium has 25%, this raises the octane easily.
My car is designed for 95 RON as per the manual instructions, however once I tried 98o I never went back to 95. As you say, I don't feel more "power", but when I go uphill I can't hear the valve rattling I heard with the 95 (I don't know if that's the right expression, I'm not english-speaking) Edit: 1.4 turbo engine, 9.5:1 compression ratio
My wife's car (SkyActive Mazda) will run on 87 just fine and gets a huge bump in torque and no heat soak power drop off on 94. The difference is quite noticeable. But that will happen when the cam timing is variable making the dynamic compression go from 9 to 1 all the way up to 12 to 1. With control over the intake and exhaust cam you can do that.
Yeah the SkyActiv ECUs are pretty complex and dynamic with how they modify the valve and spark timing. Both my Miata and my wife's Turbo CX-5 can run on 87 or 93 but we try to run 93 most of the time. The motor was designed around using it and I'd prefer to stay within the spec as much as possible.
@@carstennobody7047 I think you should take your own advice. I only build 1000hp stock bottom end turbo LS motors in my spare time because I got no idea what the fuck I'm talking about 🙄 The 2L sky active motor is actually 14 to 1 STATIC. It uses both the intake and exhaust variable cam timing to bleed off compression pressure in high load situations to achieve as low as a 9 to 1 DYNAMIC compression ratio. You know, while the engine is running? Static and dynamic are not even remotely exclusive. Maybe do, instead of reading so much.
@@carstennobody7047 that sure was a lot of verbal diarrhea to not address the issue that you don't understand what dynamic compression is. You do know that in an NA engine with a fixed cam that dynamic compression changes with RPM, right? And to compare what ANYBODY was doing with engines 100 years ago to now is beyond laughable. Even 50 years ago was the dark ages compared to now. In 1971 if you said that 600hp and 600lbft at the tire was not only easy but dead nuts reliable, WHILE getting 25mpg and could still idle in traffic all day long with the AC running? You would have been stuffed into a padded room.
Man, you could have just said that the octane numbers in Europe vs the US differ because they are calculated using different methods, but it is good you didn't - we would have missed one of the most amusing and informative auto tech videos ever :)
I stopped arguing with people about Octane because there's so much correct information out there, like this fine channel. If they truly care about cars or this particular issue, they would have taken 2 minutes to look it up and be informed. They fact they still insist the incorrect concept tells me that they are not interested in being factually correct. They just want to believe.
I put cetane boosters and other additive into my diesel and even before that, I put in a few cans of injector cleaner. Car runs smoother, better and has more power. So.. but I know diesel is different. Octane rating is there so you can push more boost thorugh the engine..
In the UK it's not about octane of 99 and 95 but more the mix of bio in the fuels which drops mpg quite noticably - 95 is now E10 normal unleaded, while 97-99 so called super unleaded is E5 and there is quite a difference in mpg upwards of 5mpg difference. Some performance cars will run on either 95 or 99 but will produce more power on 99 and more mpg plus there are plenty of issues caused by the switch to E10 with older cars pre 2011 with it corroding fuels lines.
Some great content here however the majority of cars with knock detection will not go into limp mode when knock is detected. Most of them have high octane timing maps and low octane timing maps which they will learn and interpolate between depending how aggressive the knock is. Also, as much as the fuel companies would like us to believe that all the octane ratings are standardized, I have found on the dyno that they are not. In the BC province of Canada we have a Chevron fuel rated at 94 octane which contains no Ethanol and a 93 octane fuel from Shell which contains typically 7% ethanol. On the dyno the Shell fuel will consistently show better knock resistance. On a 300whp car we will typically see a 20-30whp difference when both tuned to the knock threshold, even after dialing in the air fuel ratios between the 2 fuels. The differences are even higher on more powerful engines. We have tested this on 4 different occasions including winter blends and summer blends. Here is a link to the latest test we conducted: th-cam.com/video/vdg8DJmKODs/w-d-xo.html
There are some new cars which are designed to run fine on 87 octane, but will put out more power on premium 91+ octane (US pump rating). From my 2018 Mustang GT's owners manual: "Your vehicle is designed to operate on regular unleaded gasoline with a minimum pump (R+M)/2 octane rating of 87. Some fuel stations, particularly those in high altitude areas, offer fuels posted as regular unleaded gasoline with an octane rating below 87. *For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended.* The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when towing a trailer. See Towing (page 194)."
Greetings Dude, I point you missed is the fact is that If an engine has pre-detonation, the knock sensor will retard the timing until the pre-detonation stops. This can and usually does make a big performance decline. So upping the octane can be a real plus.
I don’t know which is better or worse but it smells so much better in England. It’s got a strong stinging smell compared to our 87 in the states. The only thing that comes close is race gas at race tracks which is dangerous to inhale the fumes I might add. It must be all that corn gas we use
To those asking about ethanol in older cars- it isn't so much the ethanol that is an issue, it's the hygroscopic nature of the ethanol, and subsequent water in the fuel that can cause issues. I have been running modern fuel in 1970s fuel systems in my car and truck since it was available in the US. I run them regularly and have never had issues in any vehicles because they never sit with older fuel in them. Boat- same thing-but before storing for the winter, run 2-3 tanks of ethanol free through it. No rust in steel lines or tanks. Running a water separator is paramount on a boat in my opinion and isn't a bad idea when running a carburetor, so it catches it before it hits the fuel bowls. Cheap hoses will degrade, but they make it long enough that replacement would be advised without ethanol in the fuel. Small engines tend to be affected the worst, because they don't get run for long periods of time. I drain my smaller 2 stroke and 4 stroke power equipment after every use, and drain the fuel bowls if they will be sitting a long time. Been doing this for years with great success.
More octane, more boost, more timing, more power. I run an extra 150kw on the fuel here in Australia to what I was running in the states with the same car/same setup. Thats an extra 8psi with another 5 degrees of advanced ignition timing. I also get around 100km extra distance to each tank using 98 instead of 95. Though I don't get knock on 95 due to the little head room I have in my tune in the case of bad fuel, I do dyno around 30kw higher from 95 to 98.
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Your a bit off Many modern engines actually have a high end low octane table you will switch between one and the other if the knock sensor sees knock if it continues to see knock once it switches to the low octane tit able for the Ignition timing it will then go in the limb mode. My BMW is a classic example of this. This was even shown back in the 1980s on forge Thunderbird Turbo coops where they actually had a premium and regular switch on the - and it would control 2 different spark tables.
"higher octane does not give you better performance" is totally wrong and misleading.
There are plenty of cars (from Mazda, VW, BMW etc.) which come from the factory with different power ratings for different octane fuel (lower power with lower octane, higher power with higher octane).
If you've ever tuned a turbo engine you'll know all about engine maps dsigned for a specific octane fuel or ethanol blends. Higher octane (or e-blends) allow for more advance timing, which in turn equals more performance.
..so "myth" NOT busted, until you can get BMW or VW to write a retraction :)
What about a different view? using higher octane when doing a lean burn to try to squeeze more milage.
Can you please add the table in the comments. Thank you sir for your time and effort put in these videos.
Omg I’ve never been so wrong in my life.
I always tough + octane = more knock xD !!!
Question: do octane number degrade in time?
Like, if I put 98 octane and leave the car in the garage for 3 months does it become say 97 or 96?
higher octane fuels also taste better. I hate syphoning 91 RON, it tastes worse than vegemite.
not surprising considering only a handful of things on earth taste on par with vegemite.
Mate, Vegemite is a DELICACY
Strong stuff Vegemite, one & only reason the upside-down people get good at cricket : )
toluene and xylene taste better than regular alkane
Had to syphon a 95 e85 mix, never again
As an American, I will always increase my protection against nonexistent threats.
🤣🤣🤣
Get this dude in congress now
Dual wield?
You should have touched on the etanol levels in the diffrent kindes of fuels. In Sweden we have 10% in our 95 and 5% in our 98. Or make a dedicated video because EU has set a minimum of 10% etanol and this raises a lot of interesting questions. Especially for older engines. Keep up the good work
Is your etanol the same as our ethanol here in the states or is this a simple typo? en.wikipedia.org/wiki/Ethanol
@@higbeedoug Yes
ethanol is a modern aditive to prevent detonation on gasoline since lead aditives were banned. the downside is that ethanol can corrode aluminium parts and react with some kind of rubber used on old engines. in a nutshell you could say adding ethanol to gasoline is a way to increase the octane rate.
Brazil has 25% ethanol mixed in the gasoline. You can buy regular, additive (with more detergents) or premium (95-99 octane but usually ethanol free).
The question is how bad 10% etanol is for an older engine not designed with etanol in mind. Like you say rubber gaskets and such. I pay a little premium and fill up with 98RON 5% etanol on my old outboard engine. All other gas is at least 10% here.
Should also be noted that ethanol will break down faster than pure gasoline, so if you are filing a infrequently used engine (lawnmower, boat, generator, etc.) Or if you are storing a reserve of fuel in a gas can it would be a good idea to spend the extra couple of bucks on ethanol free premium fuel.
still the best automotive youtube channel in my opinion! Best possible explanation you can find in the whole internet I think. Perfectly presented, clear speech, exceptional technical knowledge, paired with a healthy amount of humor, an no bragging, and no nonsense or myths sponsored by God knows whom! Wonderfull my friend, love every single video you made so far! keep it on!
Greetings from Austria!
Indeed!
Auch ein Österreicher! ;)
Those impressions, especially that American accent were far from clear speech... I have no idea what he was on about!
But the rest of the video was very clear :)
but he is wrong on this one
This explains the difference between Europe and US octane numbers really nicely. I was surprised that Audis require 95 octane, but it makes sense that it actually means 91 in the states
which is the premium fuel in US and here in EU is the regular ;)
@@izgrevski056premium in alot of the US is 93. In my State it's 92. It's 91 in California for example, it can vary by state. Some stations in the US have 110 on the pump, E85 etc.
generally the fuel is the same. Its just a different measuring system. Though some engines can advance the ignition timing with higher octane fuel than what theyre rated for which increases power and/or fuel economy. Most modern engines can retard the ignition timing with lower octane fuel than what theyre rated for in order to prevent engine damage. General rule is: Whatever it says in your car manual which fuel to put in is the fuel to put in.
Yup all Silverados past 2014 have this technology.
Does not explain why my old '88 LSC got 15 MPG in California and 19MPG in Texas. Both are 93 octane as required in the owners manual. Could be the TEXAS blend had less alcohol mixed in? Say 10% less ? No I did not change the timing.
BTW I went from a refinery job in CA to refinery job in CA. The difference between fuel stops is noticeable. If you use cash.
@@warrenpuckett4203 could be all sorts of stuff. Maybe very different altitude maybe more Ethanol content as you said or maybe you just drove differently. Like maybe you had a lot more City traffic at one Place but im just guessing. Also im no expert.
@@TheDude50447 Legal speed limits are higher in Texas. I think the ethanol is the issue.
@@slycarlo8747 I run premium in mine. Not sure it is worth it or not. I average 23 mpg highway.
Great video! i got tired of explaining to friends just what you said in the video.
Another misconception i hear a lot is about ethanol making more power than gasoline
Ethanol actually has a lower energy content than gasoline, so if all things are equal, it either makes less power, or takes more fuel to make the same power
What actually makes more power is the higher Timing/Compression ratio/boost that ethanol allows you to run in relation to gasoline.
Then you got more power and move the vehicle "effortless", why still worst on fuel economy?
If a vehicle has the capability from the factory to run e85 it is possible to make more power than gasoline without any other modifications. The reason is that the spark table will change based on conditions and input from knock sensors. Less knock and colder combustion means more spark advance
@@Carlos.Rivera because, like i said, ethanol has a lower energy content, to make the same power, you must run a richer A/F ratio, you are always using more fuel to move the vehicle irregardless of the power it makes in relation to gasoline.
@@jamesd2863 yeah, that's why i mentioned timing. In Brazil most cars are flexfuel, and make around 3-5 more HP when running E100 than gasoline (actually E27, not pure gas)
E85 fuel for example has an approximate octane rating of something like 114 and also has colling effects. Ergo you can generally run more timing and boost with E85 fuel than standard gasoline. Even though you will be using more volume of fuel, at the price and availability at many pumps it can give you comparable performance to race gas and cost less and be easier to get.
Thank you a lot for this informative video! The prejudice that the US uses inferior fuel keeps persisting strongly here in Germany.
For inferior fuel, in rural Mexico cheaper 80 octane fuel used to be common. However, low compression engines with the timing retarded would run fine on it. Which is why the air cooled VW's and older American cars were popular as both had low compression engines...
@@davidhollenshead4892 interesting. Here in Germany 91 ROZ fuel was abandoned completely by 2008. 95 Octane is standard since that.
Some manufacturers have played around with variable compression engines, and we may see more of that as emissions and economy standards tighten. For now, a similar effect can be achieved with variable valve timing being able to transition from Otto cycle to something like a Miller or Atkinson cycle.
Even though the Europe octane number is higher for the same fuel than in US, based on the video if eu 95 = 91 in us, we got higher octane fuel here. The thing is that you cannot buy anything less than 95 here in EU, but in US you got 87 which would be like a 90 in EU (according the the table in the video).
there are many station has 98 or 99 too not just the regular 95 with e10 or e5, but they are fukin expendives nowadays.... :D
In some western US states like Colorado they have gasoline with an octane rating as low as 85.
@@chrissimmons9969 I believe it is because of the thinner air at altitude.
I believe you can still buy 92 octane fuel in Europe at some petrol stations.
@@Bamsebrakar2011 Not so sure about that. In central europe for example you can find "91" on some fuel stations price thingy and a nozzle for it, but it costs the same as 95, as it is actually 95. It's mostly older fuel stations that have not yet been renovated and the 91 labeled parts removed or relabeled. The raffineries here (like the ones from OMV for example) don't even make anything less than 95 anymore. (Hence the same price for "91" and 95 on the few stations that still have labelled "91")
Yep that’s what all Americans look like but you forgot to say y’all.
Great video! I can't even count the number of times I've seen people say they use higher octane fuel "because it contains more energy" on a low-compression engine!🕵♂
I worked as a fuels chemist for years. This is a good and simple explanation of octane number and thankfully does touch on the R versus (R+M)/2 methods for certifying knock performance. This is what misleads Europeans into thinking that their fuels might be "better". In reality, the American specification is harder to meet due to averaging motor octane into the rating, where the "M" is the anti-knock performance under load. Also, octane rating is only one data point among many in certifying a finished fuel. I recommend comparing ASTM D-4814 to whatever the equivalent European standard is for a more comprehensive comparison.
Apparently many tuned cars imported from Japan blows up when American fuel is used. So there seems to be some differences in fuel quality between countries.
Erm.. The regular fuel of USA is 87 or ron 90.
In europe the normal is ron 95. We do have better fuel. Just sayyin.
@@cossiedrifter also, every one of those cars are 20-25 years old with 30k miles. Nobody wants to open, clean and re-seal before restarting and it just dies.
@@nagyandras8857 far from it buddy get your facts straight your guys regular is on par and the same as our regular, remember we all get our gasoline from the same place it’s just rated differently
@@aceofspades9833 yer regular is ~ron 92 at best.. our worse is ron 95.
that simple.
You are just BIG, bro! I watch your work from a few years and you explain the things how suppose to be explained in the university! Thank you!
Always the best automotive channel with clear and precise explanations, but acting? I was not expecting that! This is as good as the greeeeen screen shenanigans. Congrats and once again, thanks for the video.🏆
Been having this argument for 40 years! On older cars it does allow for a timing bump which does give a little bit more.
Aren’t many of the new engines adjusting ignition timing depending on fuel? I remember hearing different power figures stated by manufacturers for "regular" vs. "premium".
I think this was the case with Mazda at least.
Only if the engine is supposed to run on premium. Running such engines on regular can cause pre-ignition which will cause the knock sensor to send a signal to the computer to retard the timing, which will result in a loss of power. It could also possibly lead to engine damage. Use a fuel with the level of octane recommended in the owner's manual for the vehicle. Nothing more, and nothing less.
@@dancancade7101 nothing beats when poor fools put gas in a diesel engine
Note got a cam am spyder recommend fuel is 97 USA so am left with using 93 all the time
@@dancancade7101 That's not necessarily the case anymore. Various manufacturers will say you will get peak power running premium, say 91 octane, but the car is still able to run 87 octane safely.
@@chickenfishhybrid44 if "peak power" is obtained by the use of a higher octane fuel, then that’s what the engine was designed for. Either the engine has higher compression or it's supercharged/turbocharged and the use of a fuel with lower octane will result in the computer adjusting according. What's the point of buying such a vehicle if the plan is to run it on low octane and never get the level of performance that you paid for?
First time I've seen this explained correctly in a video. Good job.
I can't get anything lower grade than 95 RON in Switzerland, while regular in the US is ~90 RON. I tend to use 98 octane in my motorcycles (95 octane contains up to 10% ethanol which is an issue for my models) and in my "other" car which specifically requires 98.
In the US, it varies by region. In most of Texas, you would get 92 RON equivalent, somewhere like California will be lower, and Northern New Mexico starts at 88 RON equivalent.
This correct. EU 95 (91 NA) is often minimum, where in NA 94 (98 RON) isn't always available. NA has a lower availability of Premium fuel.
Ya we simply don’t have “regular” in Europe and the lowest is “premium” 95RON / 91AKI
@@ua1054 yea premium fuel for keeping the working class poor prices.
98ron is 2.30 per litre in my country lol
In switzerland we don't offer lower than 95 neither E10. Highest rating here is shell 100RON V-Power Racing, only germany has ultimate 102.
So nice of you that you also include diesel engines, most youtubers act like they don't exist
While true for driving to the supermarket or normal commutes, I would add that there are exceptions to the more octane than recommended does no good rule. In extreme applications where heat build up in the engine is expected, a slightly higher octane than recommended can help.
Example: towing with a gas v8. Most trucks in the US require regular gas, but premium can help eliminate knock in a heat soaked engine, helping with power and fuel economy. See also rock crawling, and drag racing.
In drag racing a turbo 4cyl that required premium (93 r+m/2), I've had good results with mixing in no lead 100 r+m/2 to bring the average up as high as 95. Go beyond that the specific vehicle's requirement to keep knock in check in the specific application, and performance will begin to decrease.
Also helpful on long climbs in high altitude mountains where the thin air reduces cooling.
thin air reduces compression and temperature is lower at altitude
basically the higher you go the richer your mix
My old Harley starts to knock at idle in the summer - if I'm at a long red light.
At altitude, I believe you need less octane. That’s why you see 85 in Denver.
I get why you may opt differently in a fully loaded older engine that may have hot spots though.
@@Thatdavemarsh My specific experience with mixing 100 no lead from a VP station was low mileage high compression NA motor with direct injection that required premium fuel.
I initially purchased the 2013 BRZ in Denver, and performance was deplorable. A VP station in Albuquerque NM with 4 gal of 100 R+M/2, and filling up at every 1/2 tank provided a record MPG on a trip from there to SLC, UT. 40-50% better than the trip to ABQ. I could feel the car reducing power after every fill. The performance was completely unexpected.
The VP fuel was over $5 a gallon, which was insane at the time. It was about the same as the other 7+ gal of premium I put in at the same station. I still saved money over the entire trip because of it. If only I could get it for that now.
I believe the octane ratings at high altitude are specifically for old engines. The distribution model was set up during the age of carburetors and distributors. Modern engine management can take advantage of the better fuels.
*petrol
-petroleum, liquid
Gas, LPG, is a gas.
America needs to really get on board with not being the only country to do something differently for no reason, especially as it's stupid.
I've noticed that as prices go higher the quality goes lower. I use to get over 500 miles a tank filled up yesterday with a range of 417
Excellent! You'd fit into the mid western state seamlessly, man! 🤣
Some 25 years ago, I was working at an airfield. One day a jerrycan with some 10 litres of Avgas, 150 octane aviation fuel, was left over. As my Volvo 244 had no catalyst yet, I was the lucky one to win free fuel that day, yay! 🤗 There was about 15 litres of 95 octane in the tank left when I poured in the Avgas. I had never before heard my trusty old Volvo run _this_ smooth. Like a V12, like a turbine! That being said, the B21E engine was a rather gentle character to begin with. That was a very very lovely car indeed!
When you try to be a bigot yet, have no idea what you're talking about.
Hahahaha!
The engine's ignition timing was wrong , there was a cooling system problem or the cylinders had severe carbon deposits,if what you say is true. They are the only diagnoses that can be deduced from what you describe.
@@paulg3336 Nope, the engine was enjoying best health. Back then I didn't have the knowledge to check such things myself, there was a retired mechanic living next door to did such jobs for small money. Brilliant lad, he knew 100% what he was doing.
As I didn´t speed with my 244, I did obviously not have a chance to notice any performance differences, but I did notice that the engine sound changed and the bugger felt more gentle in general until I put fresh 95 into the tank the next time.
Thank you....Some times I've noticed that R+M/2 on gas pumps but always forget to look up what it means
One of the cars I have driven specifies a minimum of 87 (R+M/2), but can go up to 93 as stated in the user manual. It delivers best performance at the higher octane ratings, since it can advance the timing before knock occurs and uses the knock sensor to bring the timing back if 87 is in the tank. So while it is mapped for and can take 87 octane, it does benefit from a higher octane gasoline in the tank. I think this is great since if you're on a highway trip you can fill up using cheaper 87, but if you want to do any performance driving you can still get the maximum out of a higher octane like 93.
Exactly my scenario as well. In cold frigid winter I will use 87. Summer, AC on, 93. My car has adaptive timing and knock sensors. Great comment!!
@@Twobarpsi why 87 during winter? simply because it's cheaper?
@@FakeMichau the air intake temperatures are so cold, less chance of detonation on my normally aspirated commuter car.
Regarding compression ratio: is the swept volume into the minimum volume. Using a domed piston decreases the minimum cylinder volume while maintaining the same swept volume, hence a higher CR.
As a Texan, I can confirm we talk like this.
And ya'll have the best dang steaks anywhere in the world ! My bikes might run on premium, E85, or C16, but I run on Angus !
in in college i had a combustion class and we had a big calobrated octane tester. gotta know that the difference between stations was more then the difference between the octane levels at the pump. ever since it leaves the refinery its continues to change octane as stuff gasses off. the cheapest gas did the best, probably because more people buy it and gets more turnover and has consistently fresher stuff. they also did the best for the lowest water content for the same reason. it was like valero that was above shell, chevron and the like. I've never had problems with ethanol in my old cars but maybe its because I get the cheap stuff that's dryer.
ethanol absorbs water while gas does not, so it does provide some protection if water is an issue in your fuel. the issue with using it in older cars are the rubber components can get eaten away over time, its not going to effect the running of the engine. I've pulled the injectors from my jetta with 120k kms and the seals were in better condition than a car with only 40k, I only run 94 which up here in canada is required to not have ethanol.
@@Born_Stellar gas obsorbs water too all the time but in large gas storage tanks the ethonal drops out into the water sitting on the bottom. and when the water is drained away along goes the ethonol. and because ethonol is the primary octane booster now the gas has a lower octane.
Ethanol free gas is good for carburetorated engines that are going to sit for a while. Gas with ethanol can gum up your carburetor if it sits a while.
@@xidarian the gum is the oil additives the put In all gas. If you leave your peacock on and the bowls are continuly full and evaporating off what's left behind is the oil additives. it will gum just as quickly with non ethanol fuel as ethanol fuel. It reely doesn't do that mutch but people will blame all their woes on ethonol.
Australian 91 has 150ppm sulphur making it dirtier out the exhaust on top of being lower Octane. Definitely seen better economy with higher octane fuels on modern motors, like the timing increases once it works out it's not knocking.
Fantastic explanation of the sometimes mystery surrounding octane and whether higher octane leads to better performance. Thank you.
It actually does lead to better performance in turbo engines, they usually are recommended to run on 98 ron/93 aki and thats where they have their advertised power output in older turbo cars, but they still can run on on 95 ron/aki just fine, justbthat it will be will slightly pulled timing hence lower performance.
Naturally aspirated engines CAN benefit from higher octane with engine mapping tuning and more aggressive ignition timing on 98 ron. So its not like there is no gains to be had from running higher octane, but it requires extra steps to be taken to actualy experience those with na motors.
I actually never knew this...very fundamental concept and very very informative video...thank you very much 👍
The UK situation is confusing because the government has created a link between octane rating and ethanol content. 95 RON petrol is E10 now but the 97-100 RON fuels are allowed to stay as E5. As E10 (in theory) has 10% ethanol, it has lower energy content than E5, so in this case the higher octane fuel does contain more energy, but not because of its octane rating.
In practice, E10 only legally means "up to 10% ethanol" and some batches turn out to have no ethanol in them at all.
Higher octane fuel allows you to add a bit of spark advance. The actual amount of power gained is always less than about 5% in ideal situations, and typically it is negligible. If your car knocks on acceleration then use premium. If it doesn't then don't put it in; In any case follow the manufacturer's instructions.
This is the reason why whenever possible, I try and run nearly dry the tank on my jeep and fill with 93 (US) before towing near max capacity for long distances. It doesn't allow the engine to make more power, but it does keep it making max power when pushing the engine harder, which also means I actually get a (1-2 MPG measured) increase in fuel economy on those long distance towing trips. I've made the same trip with the same load multiple times (track day towing) so I was able to verify.
Al si skinuo Amere,svaka cast ! :D Oplakah
Imam auto iz 2001god. i drago mi je sto sam pogledao ovaj video,ustedeo si mi novaca, hvala! :) Bome si detaljan u objasnjavanju, svaka cast!
Some manufacturers (like Ford) will rate a car for 87, and rely on knock retard to keep it alive. The 3.5L V6 Ecoboost is a prime example of an engine that gets substantially better fuel mileage and torque output by running 93+ in the 87 rated car. You'd never catch me running 87 in a GTDI engine, regardless of what the manufacturer states. All of these claims I've made have been verified by thousands of ecoboost owners with aftermarket tuners and dataloggeers. It's pulling timing all over the place on 87. Get the OAR (Octane Adjust Ratio) above .95 and they come alive on the stock calibration.
According to Andre at HP Academy, the Subaru platform also have an aggressive timing strategy that lives on knock retard, but on any pump fuel lol.
I had a Ford Focus ST 2.3 Ecoboost, which was rated at RON 95 (91 octane in the US). I think RON 98 was just better and so that was always my choice (or better!), but once I made a test: Run with RON 95 (91 octane in the US) and give it some full throttle moments on the Autobahn. OAR was at .77 and the case was clear. Top speed died at 255 - way below the possible maximum - and it was thirsty, too. Later on there was another test: This engines works totally fine with E10 (RON 95 with 10 % ethanol), but you may not push that engine too hard. If you push it, you'll better have a higher octane fuel.
I've seen differences even on the 3.7 NA V6. Rated @ 306hp in Mustang spec, some dyno pulls have shown 12-18 hp increase just switching to U.S. pump 93.
Why then? Are they nuking their CAFE on purpose?
@@misham6547 it's affects performance and longevity alot more than mileage. As long as it survives the warranty period nothing else matters.
@@michaelallen2501 but if you decrease boost and retard the timing you leave effeciency on the table. Ford could have gotten a couple more mpg on EPA and then wrote something like you can put in regular but premium recommend
Actually most modern engines are programmed to deal with the reduced octane number fuel by reducing throttle (or more diluting the intake air by the recirculated exhaust gas) together with the timing readjustment without going into limp. So when you use lower than recommended octane rating fuel, the car runs without setting any error, but has reduced performance. Then returning back to the recommended fuel rating will "boost" the performance back.
With modern turbocharged engines with intercooler the engine performance (torque and power) are electronically restricted anyway (to prevent overload so excessive wear of the other drivetrain components and heat management issues in the engine), so the change with the worse fuel is even not noticeable. Maybe the lower octane fuel does not allow the engine to operate in a more efficient region, so may cause worse mileage, but the price difference uses to eat this benefit away.
But all that is relevant only when using worse than recommended fuel (of course assuming it is still permitted by the manufacturer, e.g. as an "emergency use" or so fuel; e.g. Golf V with 77kW 1.6l - the manual explicitely stated the recommended is 95RON for full performance and minimum 91RON with expected reduced power).
What if the fuel is so poor quality in certain brands, that only the premium high octane fuel lives up to the needed standard and thus the statements?
While I can't speak on the world as a whole I can safely say that Most places in the world have fuel production extremely well regulated and encountering "Bad gas" is simply not a thing anymore. Back in the 60s and 70s sure but modern day fuel is very consistent. Similar thing with motor oils ironically. The absolute cheapest oils today are better than most of the top tier oils from 30 years ago. In the US fuels are tested regularly and have significant fines for companies that fail.
Best ending ever! Thanks for explaining. Now I know more about the American way of knock resistance display.
you're so talented in acting and fuuny in a hysterical way...great impressions i laughed my hat off 😆😆😆
In France both research and motor numbers are displayed in gas stations. I have always wondered what it means, thanks for the explanation !
I enjoyed this. Learned a lot more than engineering school.
I had hell owning a euro shop in USA where owners would assume RON numbers fit octane.
Havoc ensued.
The compression ratio can indeed change in modern engines. This can be done with variable valve timing, and variable boost pressures in cars with Turbos. These are all compression ratio modifying tool, which is why they get used in the first place.
No these doesn't change the compression ratio.
@@MrTorarp It 100% does. That's literally the whole point of these two devices. A turbo lets you compress more air and fuel into the cylinder, and variable valve timing can change how early or late the valves open, again modifying the volume of air and the rate at which it gets compressed.
Engines are compressors. That's all they do.
@@Nabeelco No you're wrong. Compression ratio is defined as the volume of space at bottom dead center versus the small space at top dead center. How much air you put into that space does not change the compression ratio. What you are changing with turbo/super charger is another engine characteristic called "volumetric efficiency".
In our region (Maritimes, Canada), the bottom two grades may contain up to 10% Ethanol, but the 'Premium' grade typically does not. So that's a factor that was not mentioned here. Your regional circumstances may vary.
I recall that my 1986 VW GTI supposedly had adaptive spark advance, constantly advancing the ignition timing to just before the point of detonation. So the spark advance was governed by the fuel. Buying the best fuel (Sunoco Gold) made an obvious difference, and No, I wasn't just imagining it.
Present vehicle runs 16 psi boost, so I'll take the best gas thanks.
Only Shell as far as I know, esso and petro Canada and the lot still mix it in
The spark advance on an '86 GTI is good for about 5 hp in ideal situations. So you went from 105 hp to 110 hp; I hardly think that would be noticeable.
By the way, by turning your distributor about 5 degrees counterclockwise you can achieve the same thing, but listen for spark knock...
@@Flies2FLL The 86 VW Golf GTI is very light, weighing under a tonne, so bumping power from 105 to 110hp would be noticeable!
I've always drive small cars & in some cars I'd notice the power difference when changing the fuel filter or air filter :)
@@jayr6637 Those weighed about 2300 pounds. I drove an '85 Scirocco turbo for 8 years, and one thing I noticed about the car was that a long drive on the interstate highway really made it run good the next day. It felt much "snappier", though I doubt it had any more actual power.
A 5% change in power will be barely noticeable, if at all. Trap speeds in a quarter mile will show the improvement.
@@Flies2FLL A buddy of mine had an 86 Golf GTI 3 door. His definitely weighed under a tonne, about 920kg... maybe they weighed more in the US due to regulations.
Anyway, maybe it's because I've never owned a car weighing over a tonne & have always owned NA manual cars, but I notice small gains... especially on familiar roads :)
My understanding is that some engines can adjust settings to take advantage of higher octane and produce more power. In 1996 Honda released a 1.6L Civic on the New Zealand 🇳🇿 market which had a budget style fuel injection they called Group Injection. This had only two fuel injectors which I felt at the time was a major step backwards from PGM-FI. However, group injection was also paired with a knock sensing system which Honda claimed could sense and adjust to a different octane rating in every engine cycle - very impressive capability from something that is impossible to achieve in a practical way. In 2000 when 98RON fuel ⛽️ became available in addition to 95RON premium and 91RON regular, Honda NZ claimed a 5% power benefit from 98 in my 1994 Integra VTi-R over 95. I did notice an improvement. Currently I run 100RON in my Mercedes CLK 320 W209 and it goes like a rocket 🚀😀
Interesting video. I was just talking about this in my video on my imported Mercury Grand Marquis which I imported here to Europe. The caveat is that in the US, it’s customary to fill up with the standard 87 octane whereas here in the Netherlands, euro95 is the standard which is the equivalent of 91 in the US. So in my case, I am putting better fuel in it in the context of octane rating.
Unfortunately using higher octane on engines that make no use of higher octane is a waste of money (here where gasoline is cheaper than octane additives) and can actually lead to efficiency problems. Really cool that you decided to import one those though. 👍
This is so cool... finally someone that can explain these aspects in a way that everyone can understand them Thumbs Up
There is one thing -- higher octane also often has better additives to help clean the engine and valves (more so with indirect injection). Not always, but often it does. I sometimes grab a higher octane just to pretend and hope it cleans the engine better, and even if I grabbed a full tank (50 litres) it is close either $2 or $4 difference usually.
Or some petrol stations offer normal "95 pro" which should have better additives, usually cheaper than 98 but ...
your mileage may vary (literally) though :)
I commented above before seeing your post. I do the same as I'm pretty sure premium has better or more additives.
I'm not sure that is correct
This is highly dependent on the brand of gas station. Some put more detergents and other stuff in higher octane fuels, others put the same amount in all octane ratings.
This is certainly not always true. Basic additives are always included in all fuels. Additional additives are added by the station thus if you want more additives, the best way is to buy it yourself and add it to your tank.
The best way to get extra stuff is to buy a name brand gas. Going to Costco and getting premium is not going to cut it.
I had a 92 Isuzu pickup with a 2.3l two barrel carb. I had a job that required me to drive one hour each way on an open stretch of I-10 4-5 days a week. So I tested all grades of gasoline for 6 months. 87=24mpg, 89=25.5mpg, 93=23mpg. I had to fill up every 2 days. So I tested them all alot. This was also back when all grades were only 10 cents apart, but those are the results everytime
Im wondering whats the highest pump gas you can get in the US? Cause that could be comparible. In Germany for example the highest pump gas Rating you can get is 102 ROM which would be around 97 in the US. But you can actually get it all over Germany. There are a lot of gas stations where this is available.
depends on which state you're in. but premium falls anywhere between 91 and 94 octane. 91 where i live.
I use that gas in my carburated racebike. Engine runs better in the high rpm range
Vincent Rohrig, greetings, around where I live( Wisconsin U.S.A ) you can get, although it's designed for recreational off road use only, ( I use it in my sportbike when I spend a day on my local racetrack) 98 octane (antiknock index RON+MON divided by 2 ), or just RON( I think around) 103 or 104 ( your system of measurement). This fuel also has 2 extra caviats, 1 It is true GASOLINE, that is it is Not ethanol and does not contain any alcohol, and 2 This fuel contains lead. Leaded fuel was phased out in the United States I think around the early 1990s because of leads high toxicity. Lead was introduced by Dupont corporation I think around 1920, as a means to boost octane ratings of motor fuel, as well as being a lubricant for valves. Also, this fuel can NOT be used in the majority of road vehicles because the lead will in short order destroy a car's catalitic converter. I can use it in my old zx7 ninja safely since the bike has a race pipe on it and is sans catalitic converter. By the way, you are very blessed to live where you do, as a longtime somewhat knowledgeable Motorsports fanatic I realize your general populous are FAR higher skilled drivers than the lacidasical drivers here in the states. Just curious, do you by chance live near a derestricted portion of the Autobahn?, If so how often do you see exotics and hyper cars flying by in the left lane at, oh say 300 k.p.h. or more? That would be a awesome sight! Thanks for sharing. Cheer's!!!!!!
@@Sjef0194517greetings, what kind of racebike do you have, and what tracks do you ride? I have 2 ninjas, a ancient ZX 7, and a zx6r. My home track is road America, Elkhart lake. They just held the Indy car race here last weekend, that track is so beautiful with 3 long straights. Thanks for sharing. Cheers!!!!
@@steveapel2961 Hi Steve
I ride the F1 circuit Zandvoort in the Netherlands and the motoGP TT circuit Assen foremost. Both are extremely fun to ride. And the plan for next year is to ride Spa-Francochamps in Belgium as well.
I do this on a old 1999 Suzuki GSXR 600 SRAD. and trying tot get under 2 minutes on both tracks (fastest for a bike is 1:52min)
I'm Brazilian, and Brazil is moving to RON. Excellent video.
On more advanced systems higher octane will cause the engine to advance timing and actually produce more power .
exactly, on high compression ratio engines where you have high timing targets and advance timing you will create more power. That is why when they remap / tune the ECU's other than adding turboboost among many other things, advancing ignition timing is always one of the things they change. More advanced ignition timing = more power. This video is only half-true and doesn't really go in depth with other scenarios.
I’m so glad that you explained this. I can direct my friends who believe that higher octane fuel has more power than lower octane fuel, to your channel.
Look, they are all misunderstood.
For example, I drive a 2019 VW GTI, and on the gas lid, it says, unleaded fuel only, 87, 89, 91.
Now if I pump 87, the car won't have the same HP to the wheel.
The GTI supposedly comes with 226 HP to the wheels, so if I pump 87 I'm not getting 226 to the wheels, if I pump 89, I won't get 226 to the wheels. Now if I pump 91, I will get the full performance of the engine.
Now I can pump higher octanes passed 91, and that won't add any HP or have any different effect.
My engines max output is 226 on 91, so pumping higher octane won't do a dang thing. This goes with every vehicle.
Higher octane = more energy (kJ/kg) because of less ethanol
The real question nowadays is who GOT the fuel.
Thank you very much, I will now quality test my tub of cooking oil by getting their octane rating every once in a while.
Well, is it really mythbusted? The highest octane rating available in the US is 93 premium which is basically 97.5 RON in Europe. Yet every European country has 100 RON available.
i don't know other countries but in Portugal you only have 95 and 98.
In Germany at Aral gas stations you can get ultimate 102
There's plenty of gas stations in the US, at least around me, that sell 100 Octane and even 110. Classified as "Race fuel"
@@chillycheeese haha, yes, full of ethanol and the blend has even less energy content than 95 :D
@@zochpeter "Full of ethanol" - sure, the mandated 5 percent.
However, it has a higher ROZ octane rating and such enables certain engines to produce more power.
Also, could you please provide a source for your statement with reduced energy content?
interesting thought from an explosives expert here.. when two blast waves collide, they magnify at the point of intersection (known as the mach stem effect) these colliding shock waves are many many times more powerful than either of the initial Shockwave (we induce this effect to get better performance of explosives with less explosive material) this sounds like it is a contributing factor in knock causing cylinder damage
Love the accents 🤣🤣🤣
I like the old octane testing machine in the video. The “knockmeter” at 7:54 made me chuckle a bit.
Venezuela has better fuel though....
It's only 2 cents per liter
I just wish my southern American accent was that good!! I'm from the southwest US, about 6500 ft above sea level, yet I don't hear anyone complaining about octane numbers! I won't complain about 87-91 octane, because these days, we'll take anything we can get! Diesel shortages are already affecting local businesses. When my turbocharged "racecar" needs gasoline, 91 octane is noticeably better for performance than 87 octane. You couldn't change my mind.
The map on my engine, is designed to work only with 99RON UK fuel.
It would be dangerous for me to use any less.
And it does make more power on higher RON rating, as proven on a dyno.
Decent video, but over simplified to suggest lower octane will give more power, completely wrong and the opposite is true. It's not a waste of money to use higher RON fuel, as proven by 1000's of motorists who get a much better fuel consumption with higher RON, and in fact, save money by paying a little bit higher price for the higher RON fuel, but get more mpg which actually works out cheaper for them overall.
One thing you're missing is that some manufacturers like BMW, Honda, Ferrari to name a few have higher compression ratios (and/or boost), then tune timing and valve control dynamically based on a measurement module. In BMW cars it's known as the ionic sensor, where it uses the ionic content of the combustion cycle as measured by the spark plug electrodes to relay more precise information about knock conditions to the ECU, allowing it to respond to higher octane gasolines, up to the engine's max potential of course where it can operate at optimal timing and valve lift.
That still means (western) Europe has better fuel than the US.
Our standard fuel is euro95, which is equivalent to 91 in the US, which is always marketed as premium fuel.
I have never seen the equivalent to US regular gasoline, here.
It depends on which state you live in. Where I'm at we have 93 Octane fuel everywhere. But according to his chart, Europe technically has 94 Octane fuel, which in theory is slightly better than what we have here lol
Small price to pay for paying $12 a US Gallon vs current inflated price of $5 a US Gallon. BTW, in Russia it's still .50 per liter ... I don't thing the "Boycotts" are working in our favor ... a question for "Davos" participants n'est pas?
@@craigsowers8456 Thr Russians also have an average wage of a few hundred dollars a month, so to them that .50 per liter still feels like a large purchase. If they spend let’s say $32 per tank 2-4 times per month, that’s a large chunk of their income just on fuel
As other comments are also talk about alcohol level, I keep it short. Alcohol per volume created less heat than pure gasoline and so if in high octane fuel we have less alcohol, therefore per volume it must create more energy. Of course I already accept that I am wrong because you are the GOD of engine Sir.
Yes, the ethanol content definitely plays a part, you're not wrong at all and I'm only human. I avoided speaking about ethanol in the interest of video simplicity and brevity. I'll try to do an ethanol video in the future
Octane has nothing to do with the quality of the fuel. End of video.
The benefit of higher octane is actually beneficial in carburetor vehicles. It allows you to advance your timing a few more degrees for a bit better performance.
Your impression of a Texan is scary accurate. Liked the piece at the very end.
"(ron + mon)/2" as octane rating smh. this just goes to show the length america is willing to go to not use standard measurement the rest of the world uses. americans probably think it's edgy but it's actually cringe.
In England we have 95 Ron unleaded that has just had it’s ethanol content increased from 5% to 10%. We also have 98/99 Ron “Super” unleaded with 5% ethanol content. Of course, in the good old days of leaded petrol (that smelt so much nicer!), we also had 101 Ron “5 Star” that was used for performance cars; “4 Star” was more most normal cars and “2 Star” was for economy low powered cars.
Learnt something that I never knew about today! Thanks again Mr D4A!
Very good imformation I always thought higher octane increases performance, your topics certainly help take away the myth thank you very much, it all comes down to tuning and knowing your compression ratios awesome.
Excellent discussion on octane numbers. Many premium cars actively adjust timing depending on the fuel in the tank, easily perceptible when driving. And yes, using recommended octane gives the best results. But, as noted in other comments, there can be other considerations besides octane when choosing what button to push at the pump - ethanol and additives. Typically, there is less to no ethanol and more additives in premium fuels. Many mechanics swear these are important if you’re going for long engine life. Myth or fact? It would be great if you could weigh in on that.
You’re completely right, however what you are missing is those of us that run older cars and 98 being the only way to get e5 instead of e10, at least in Europe.
I believe you did a good job here. And a lot of good comments here too 👍. I personally use non ox premium in all my small engines, marine and powersports engines and haven't had issues. Ethanol works in vehicles that get used often so the fuel is kept fresh, but can be disastrous for small engines and stuff that is sits for long periods. Because ethanol does degrade fast and also absorbes moisture so it can phase sperate, another bad thing!
I have cleaned and repaired a lot of those fuel systems. Also there is less energy in alcohol so it can slightly reduce fuel economy, but the price difference for non ox fuels usually negates that. However I have also seen studies and heard opinions that suggest the use of ethanol has no overall net gain for us all.
Something to be said about engines that have adaptive fuel capabilities, my FRS would 'gain' power up to about 94-96 octane, and derate significantly on regular. Also ethanol content can make a difference in power and fuel economy. All this without throwing codes.
In Brazil since 2020 the method used is RON, our regular gasoline has 93RON and Premium has a minimum of 98RON, but the most sold premiums have 102 and 103RON, our regular gasoline has 27% ethanol and the premium has 25%, this raises the octane easily.
As a French that moved 4 years ago to Canada, thank you for explaining that number difference between Europe and North America
Explained absolutely perfectly.
Excellent video that answered many questions I had. Thanks.
awesome video loved the merican interpretation
My car is designed for 95 RON as per the manual instructions, however once I tried 98o I never went back to 95. As you say, I don't feel more "power", but when I go uphill I can't hear the valve rattling I heard with the 95 (I don't know if that's the right expression, I'm not english-speaking)
Edit: 1.4 turbo engine, 9.5:1 compression ratio
The most common stupid statement ever. EVER! Placebo effect.
Another excellent episode
My wife's car (SkyActive Mazda) will run on 87 just fine and gets a huge bump in torque and no heat soak power drop off on 94. The difference is quite noticeable. But that will happen when the cam timing is variable making the dynamic compression go from 9 to 1 all the way up to 12 to 1. With control over the intake and exhaust cam you can do that.
Yeah the SkyActiv ECUs are pretty complex and dynamic with how they modify the valve and spark timing. Both my Miata and my wife's Turbo CX-5 can run on 87 or 93 but we try to run 93 most of the time. The motor was designed around using it and I'd prefer to stay within the spec as much as possible.
@@carstennobody7047 I think you should take your own advice. I only build 1000hp stock bottom end turbo LS motors in my spare time because I got no idea what the fuck I'm talking about 🙄
The 2L sky active motor is actually 14 to 1 STATIC. It uses both the intake and exhaust variable cam timing to bleed off compression pressure in high load situations to achieve as low as a 9 to 1 DYNAMIC compression ratio. You know, while the engine is running? Static and dynamic are not even remotely exclusive. Maybe do, instead of reading so much.
@@carstennobody7047 that sure was a lot of verbal diarrhea to not address the issue that you don't understand what dynamic compression is. You do know that in an NA engine with a fixed cam that dynamic compression changes with RPM, right?
And to compare what ANYBODY was doing with engines 100 years ago to now is beyond laughable. Even 50 years ago was the dark ages compared to now. In 1971 if you said that 600hp and 600lbft at the tire was not only easy but dead nuts reliable, WHILE getting 25mpg and could still idle in traffic all day long with the AC running? You would have been stuffed into a padded room.
As a southern man, I heard not a word of what you said but knew exactly what you were saying
Man, you could have just said that the octane numbers in Europe vs the US differ because they are calculated using different methods, but it is good you didn't - we would have missed one of the most amusing and informative auto tech videos ever :)
I stopped arguing with people about Octane because there's so much correct information out there, like this fine channel. If they truly care about cars or this particular issue, they would have taken 2 minutes to look it up and be informed. They fact they still insist the incorrect concept tells me that they are not interested in being factually correct. They just want to believe.
I put cetane boosters and other additive into my diesel and even before that, I put in a few cans of injector cleaner. Car runs smoother, better and has more power. So.. but I know diesel is different. Octane rating is there so you can push more boost thorugh the engine..
I've preached this until blue in the face but there's no reason to wrestle with a pig in mud. He's in his element and loves it.
Really good thank you for the perfect Octane explanation on Petrol engines (Gas engines).
Do you have the equivalent for Diesel and the Cetane No ?
Love this channel! Feel smarter just for having watched this.
In the UK it's not about octane of 99 and 95 but more the mix of bio in the fuels which drops mpg quite noticably - 95 is now E10 normal unleaded, while 97-99 so called super unleaded is E5 and there is quite a difference in mpg upwards of 5mpg difference. Some performance cars will run on either 95 or 99 but will produce more power on 99 and more mpg plus there are plenty of issues caused by the switch to E10 with older cars pre 2011 with it corroding fuels lines.
Some great content here however the majority of cars with knock detection will not go into limp mode when knock is detected. Most of them have high octane timing maps and low octane timing maps which they will learn and interpolate between depending how aggressive the knock is. Also, as much as the fuel companies would like us to believe that all the octane ratings are standardized, I have found on the dyno that they are not. In the BC province of Canada we have a Chevron fuel rated at 94 octane which contains no Ethanol and a 93 octane fuel from Shell which contains typically 7% ethanol. On the dyno the Shell fuel will consistently show better knock resistance. On a 300whp car we will typically see a 20-30whp difference when both tuned to the knock threshold, even after dialing in the air fuel ratios between the 2 fuels. The differences are even higher on more powerful engines. We have tested this on 4 different occasions including winter blends and summer blends. Here is a link to the latest test we conducted: th-cam.com/video/vdg8DJmKODs/w-d-xo.html
There are some new cars which are designed to run fine on 87 octane, but will put out more power on premium 91+ octane (US pump rating). From my 2018 Mustang GT's owners manual:
"Your vehicle is designed to operate on regular unleaded gasoline with a minimum pump (R+M)/2 octane rating of 87. Some fuel stations, particularly those in high altitude areas, offer fuels posted as regular unleaded gasoline with an octane rating below 87. *For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended.* The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when towing a trailer. See Towing (page 194)."
Greetings Dude, I point you missed is the fact is that If an engine has pre-detonation, the knock sensor will retard the timing until the pre-detonation stops. This can and usually does make a big performance decline. So upping the octane can be a real plus.
I don’t know which is better or worse but it smells so much better in England. It’s got a strong stinging smell compared to our 87 in the states. The only thing that comes close is race gas at race tracks which is dangerous to inhale the fumes I might add. It must be all that corn gas we use
Correct use of AU and NZ flags is a rarity on the internet, good work!
To those asking about ethanol in older cars- it isn't so much the ethanol that is an issue, it's the hygroscopic nature of the ethanol, and subsequent water in the fuel that can cause issues. I have been running modern fuel in 1970s fuel systems in my car and truck since it was available in the US. I run them regularly and have never had issues in any vehicles because they never sit with older fuel in them. Boat- same thing-but before storing for the winter, run 2-3 tanks of ethanol free through it. No rust in steel lines or tanks. Running a water separator is paramount on a boat in my opinion and isn't a bad idea when running a carburetor, so it catches it before it hits the fuel bowls. Cheap hoses will degrade, but they make it long enough that replacement would be advised without ethanol in the fuel. Small engines tend to be affected the worst, because they don't get run for long periods of time. I drain my smaller 2 stroke and 4 stroke power equipment after every use, and drain the fuel bowls if they will be sitting a long time. Been doing this for years with great success.
More octane, more boost, more timing, more power. I run an extra 150kw on the fuel here in Australia to what I was running in the states with the same car/same setup. Thats an extra 8psi with another 5 degrees of advanced ignition timing. I also get around 100km extra distance to each tank using 98 instead of 95. Though I don't get knock on 95 due to the little head room I have in my tune in the case of bad fuel, I do dyno around 30kw higher from 95 to 98.
In the US , 91 doesn't have ethanol in it. So I use that in smaller engines. Like a chain saw or lawnmower.