To do this experiment, you need to have it under pressure. Even then you won't see a difference. They will burn at the same rate and produce the same energy. Octane simply is resistance to pre-combustion in a hot cylinder before the spark ignites it. BTW, I'm a chemist.
A lot of people don't know that octane is for compression. Higher octane can handle more compression without exploding before the sparkplug goes off. Prevents pre-detonation which is bad and could be catastrophic.
if you're interested in measuring the flame front speed why not use a long, clear pipe? you can leave the ends open and put distance marks down the length. Problems are: flame front speed depends on AFR, so you need a consistent mix between tests. I have heard about 87 burning faster, but not sure.
Your side by side comparison doesn't match. You have the 93 and 87 octane labeled incorrectly. When you first lit the 87 octane there was a spark that went across the video, but the comparison, you have that marked as the 93. But still a cool video.
@@xlr8ing_zgarage yes sir. Lol. I know it's too little too late since the vid is already out. Lol. I hate having to go back and fix stuff on my other channel on a vid that I either forgot to edit or whatever.
Good on ya for having a crack at science my friend. Here are some thoughts to add to your scientific method. Why do you think this test would yield any valuable information? Theres 2 issues I see immediately: Conditions of combustion are significantly different - temperatures and pressures in cylinder are much higher than ambient atmosphere will plausibly impact flame front. At the very least as air density changes the speed of sound changes and since that is the determining factor as to whether something is a detonation or deflagration then I think it would change flame front speed. Experimental apperatus - say you have an engine at 9000 RPM (thats high for most cars but is low for motorbikes so we can take it as indicative). That is 150 revs per second, meaning every 4th cycle the flame front will completely cross the cylinder in 1/150th of a second. So your slow speed camera would need to have a frame rate at least that fast to caputure the compbustion in just 1 frame. You would then need a camera at least 10 times faster to capture the flame front with 10 frames (ie to be able to use 10 frames to track progress across the cylinder). Finally in an engineering sense do you think the flame front speed would be 10% different between the 2 fuels? If you wanted to be able to track a difference of 10% you might need to increase the frame rate even further. So the second point laregly supports my instinctive first point. The flame front speed is entirely different in cylinder, and right now I don't see no reason that they may not actualy yield inverse results. ie one might be faster in atmosphere yet be slower in cylinder. Good luck researching brother. Matt
This isn’t how octane works. Octane rating is a fuels capacity to resist unintentional ignition and there are several more factors that affect this. Octane helps combustion engines in 2 major ways: 1. Pre-ignition by hotspot and 2. Pre-detonation by compression. Both of these have to do with pre-existing energy within the cylinder. Pre-ignition finds its energy by a hotspot in the cylinder. Therefore, if we increase the fuels auto-ignition temperature, we can avoid this form of pre-ignition. Pre-detonation finds its energy from 2 places: 1. Increased pressure and 2. Increased temperature. When we compress something, the molecules are forced together increasing the number of collisions they experience. Forcing fuel and oxygen closer together on a molecular level increases the probability a chemical reaction will occur and the probability the energy released from the reaction with set more reactions off (aka chain reaction). This is, by definition, the most common definition of temperature so we have just also explained point number 2, that compression increases temperature. Both of these together reach some critical point where the fuel all spontaneously ignited at once with no flame front involved. The sudden increase in pressure behaves like an explosion and is highly destructive. Again, the solution is to also increase the auto-ignition temperature of the fuel. While there may be an actual measurable difference in how these differences in how octane ratings affect burn speeds, the methods for producing the differences in octane rating would render this experiment, uncontrolled. You can have additives the increase resistance to spontaneous ignition. These additives change the ratio of fuel-to-octane enhancer, thereby affecting how it burns or the formula that makes up the fuel can change thereby also changing its burn characteristics. We can add things to the fuel, such as methanol or ethanol which require more ignition energy, or we can reduce Volatile compounds in the fuel and make it “more like kerosene” and this will have increase the ignition energy required to ignite a fuel air mixture. Experimentally, we can’t just burn the fuels in open air to determine the effects of the different octane fuels. We would need to control precisely how much air the fuel is mixed with, how we ignited it, the pressure it is at, how clean the test rig is, what hotspots it might have, etc. and we would need to experimentally alter these variables to find its resistance to ignition to determine how fast its flame front travels. Anything less than conducting these experiments in a controlled manner is merely playing with fire.
I have a 94 Probe GT v6 5 speed. It is supposed to use premium. I used to run it on 87 sometimes, other times premium. It didn't have a problem with knock, and ALWAYS needed attention with the ignition system, and IAC due to coolant levels, occassional vaccum leak. It was pushed hard on whatever fuel was in it. After years I realized the RPMs were dropping off faster on 87. This drop in RPMs made it impossible to rev match. My 93 did this too, but that was about a decade before I bought the 94 and I forgot about it. My first thought was, I'm wrong, crazy, doing it wrong, there's an error. So I explained it to a friend that was a regular passenger. I turned it into a game where my passenger would tell me if I cheaped out on the fuel, and he was right 100% of the time. I even experimented a little bit with brands. Shell, Sunoco, BP, and Speedway (which says they get their fuel from Amoco.) Shell always ran better 87-93, in all cars I put it in, BUT still dropped revs too quickly using 87 IIRC. Sunoco used to have 95, may still but I think they have 94 as their top octane now, it's been awhile. Sunoco premium did nothing over any other gas. BP paused injector issues with some GM cars back in the day, so that place was pretty much an emergency stop even though I don't have anything GM. I stopped using lower grades of gas after swapping the engine for a .9 higher compression, and also ECU swap. Strictly a performance swap and I wanted to start fresh with all the problem areas never give it an excuse. When I used 87 the car did not feel slower, or like it had less power, it made rev matching the downshift jerk with a blip, and there was no way to compensate with the gas pedal, blipping more, without over compensating. It's otherwise nirvana when everything is perfect.
The octane is to retard the ignition to allow the piston to be at it's full design compression stroke position before the fuel ignites. It is for this reason that lower octane fuel in a high compression engine will cause the engine to knock. The fuel will ignite before the piston is in the full design compression stroke position, causing dieseling.
while there's definitely good info here, I feel like this experiment is invalid. The fuel is being stored in open containers is open air before the test is going, then the other fuel is left out and open while the other fuel is burning. fuel does evaporate albeit slowly but it does. the alcohol and ethanol ratios could be vastly different for this reason.
You may be right, as both these fuels were stored in gas cans in my garage for a couple weeks so the ethanol content could have changed. But since both fuels were stored in the same environment for the same amount of time in the same conditions I would say the 87 vs 93 flame front speed is still valid. I’ve heard that the higher octane does have fuel stabilizer added so it can be stored longer but I don’t think 2 weeks is enough to degrade the 87 octane to any noticeable degree. The 93 octane sat out for literally 5 minutes longer than the 87 in the plastic cup during the testing. Thanks for watching!
I applaud the citizen science. Will this apparatus and method answer the question ?No. But knowledge is built with failure. It took thousands of years to get to Cern.
Ethanol content screws this up. Australia sells little of Ethanol mix, just too bad for engines. Europe sells only 95 or 98 octane but their definition is different. Looking at your 87 residue one can see the reason direct injected engines die earlier from carbonizing.
Thanks for watching! Regarding the carbon build up, I’m not sure how the pistons look in a DI engine because if fuel residue, but the problem I’ve seen is mainly due to the intake valve no longer having fuel spraying on it, and carbon build up because of the oil in the PCV system. I recommend anyone with a DI engine install a catch can immediately. Thanks!
I'm no rocket surgeon but I'm pretty sure you didn't measure the thing you think you did. think high compression gasoline engine vs low compression gas engine vs diesel. octane/cetane (diesel) is a measure of the fuels RESISTANCE of SELF COMBUSTION UNDER PRESSURE AND TEMPERATURE. just my .02$ if you still want to measure the burn speed you could use a engine timing light and a high speed recording and count the frames in-between a complete cycle of ONE cylinder (from tdc to tdc) for each fuel. my theory is that the burn time is insignificant but don't give up on the science! keep going! prove me wrong! ill watch another video of your findings.
To do this experiment, you need to have it under pressure.
Even then you won't see a difference. They will burn at the same rate and produce the same energy.
Octane simply is resistance to pre-combustion in a hot cylinder before the spark ignites it.
BTW, I'm a chemist.
A lot of people don't know that octane is for compression.
Higher octane can handle more compression without exploding before the sparkplug goes off.
Prevents pre-detonation which is bad and could be catastrophic.
Constructive criticism: you can not use an infrared thermometer like that. It will be wildly inaccurate.
Thank you!
if you're interested in measuring the flame front speed why not use a long, clear pipe? you can leave the ends open and put distance marks down the length. Problems are: flame front speed depends on AFR, so you need a consistent mix between tests. I have heard about 87 burning faster, but not sure.
Great video
Your side by side comparison doesn't match. You have the 93 and 87 octane labeled incorrectly. When you first lit the 87 octane there was a spark that went across the video, but the comparison, you have that marked as the 93. But still a cool video.
Holy crap! You’re right!! I didn’t even realize. I’ll have to fix that. Thank you!
@@xlr8ing_zgarage yes sir. Lol. I know it's too little too late since the vid is already out. Lol. I hate having to go back and fix stuff on my other channel on a vid that I either forgot to edit or whatever.
@@NateOffGrid exactly but I’m gonna fix it somehow. I want it to be as accurate as I can, regardless of the outcome. Thanks!
Thankyou for an interesting video, this comment section is informative too
Good on ya for having a crack at science my friend. Here are some thoughts to add to your scientific method.
Why do you think this test would yield any valuable information?
Theres 2 issues I see immediately:
Conditions of combustion are significantly different - temperatures and pressures in cylinder are much higher than ambient atmosphere will plausibly impact flame front. At the very least as air density changes the speed of sound changes and since that is the determining factor as to whether something is a detonation or deflagration then I think it would change flame front speed.
Experimental apperatus - say you have an engine at 9000 RPM (thats high for most cars but is low for motorbikes so we can take it as indicative). That is 150 revs per second, meaning every 4th cycle the flame front will completely cross the cylinder in 1/150th of a second. So your slow speed camera would need to have a frame rate at least that fast to caputure the compbustion in just 1 frame. You would then need a camera at least 10 times faster to capture the flame front with 10 frames (ie to be able to use 10 frames to track progress across the cylinder). Finally in an engineering sense do you think the flame front speed would be 10% different between the 2 fuels? If you wanted to be able to track a difference of 10% you might need to increase the frame rate even further.
So the second point laregly supports my instinctive first point. The flame front speed is entirely different in cylinder, and right now I don't see no reason that they may not actualy yield inverse results. ie one might be faster in atmosphere yet be slower in cylinder.
Good luck researching brother.
Matt
This isn’t how octane works. Octane rating is a fuels capacity to resist unintentional ignition and there are several more factors that affect this.
Octane helps combustion engines in 2 major ways: 1. Pre-ignition by hotspot and 2. Pre-detonation by compression. Both of these have to do with pre-existing energy within the cylinder.
Pre-ignition finds its energy by a hotspot in the cylinder. Therefore, if we increase the fuels auto-ignition temperature, we can avoid this form of pre-ignition.
Pre-detonation finds its energy from 2 places: 1. Increased pressure and 2. Increased temperature. When we compress something, the molecules are forced together increasing the number of collisions they experience. Forcing fuel and oxygen closer together on a molecular level increases the probability a chemical reaction will occur and the probability the energy released from the reaction with set more reactions off (aka chain reaction). This is, by definition, the most common definition of temperature so we have just also explained point number 2, that compression increases temperature.
Both of these together reach some critical point where the fuel all spontaneously ignited at once with no flame front involved. The sudden increase in pressure behaves like an explosion and is highly destructive.
Again, the solution is to also increase the auto-ignition temperature of the fuel.
While there may be an actual measurable difference in how these differences in how octane ratings affect burn speeds, the methods for producing the differences in octane rating would render this experiment, uncontrolled. You can have additives the increase resistance to spontaneous ignition. These additives change the ratio of fuel-to-octane enhancer, thereby affecting how it burns or the formula that makes up the fuel can change thereby also changing its burn characteristics.
We can add things to the fuel, such as methanol or ethanol which require more ignition energy, or we can reduce Volatile compounds in the fuel and make it “more like kerosene” and this will have increase the ignition energy required to ignite a fuel air mixture.
Experimentally, we can’t just burn the fuels in open air to determine the effects of the different octane fuels. We would need to control precisely how much air the fuel is mixed with, how we ignited it, the pressure it is at, how clean the test rig is, what hotspots it might have, etc. and we would need to experimentally alter these variables to find its resistance to ignition to determine how fast its flame front travels. Anything less than conducting these experiments in a controlled manner is merely playing with fire.
I have a 94 Probe GT v6 5 speed. It is supposed to use premium. I used to run it on 87 sometimes, other times premium. It didn't have a problem with knock, and ALWAYS needed attention with the ignition system, and IAC due to coolant levels, occassional vaccum leak. It was pushed hard on whatever fuel was in it. After years I realized the RPMs were dropping off faster on 87. This drop in RPMs made it impossible to rev match. My 93 did this too, but that was about a decade before I bought the 94 and I forgot about it. My first thought was, I'm wrong, crazy, doing it wrong, there's an error. So I explained it to a friend that was a regular passenger. I turned it into a game where my passenger would tell me if I cheaped out on the fuel, and he was right 100% of the time. I even experimented a little bit with brands. Shell, Sunoco, BP, and Speedway (which says they get their fuel from Amoco.) Shell always ran better 87-93, in all cars I put it in, BUT still dropped revs too quickly using 87 IIRC. Sunoco used to have 95, may still but I think they have 94 as their top octane now, it's been awhile. Sunoco premium did nothing over any other gas. BP paused injector issues with some GM cars back in the day, so that place was pretty much an emergency stop even though I don't have anything GM. I stopped using lower grades of gas after swapping the engine for a .9 higher compression, and also ECU swap. Strictly a performance swap and I wanted to start fresh with all the problem areas never give it an excuse. When I used 87 the car did not feel slower, or like it had less power, it made rev matching the downshift jerk with a blip, and there was no way to compensate with the gas pedal, blipping more, without over compensating. It's otherwise nirvana when everything is perfect.
You seem like you'd be a blast at family parties. Get a knock sensor on that "Probe GT" and it would make more sense.
@@LegendaryFarm84 It has a knock sensor. It's not knock on decel with no load..
The octane is to retard the ignition to allow the piston to be at it's full design compression stroke position before the fuel ignites. It is for this reason that lower octane fuel in a high compression engine will cause the engine to knock. The fuel will ignite before the piston is in the full design compression stroke position, causing dieseling.
while there's definitely good info here, I feel like this experiment is invalid. The fuel is being stored in open containers is open air before the test is going, then the other fuel is left out and open while the other fuel is burning. fuel does evaporate albeit slowly but it does. the alcohol and ethanol ratios could be vastly different for this reason.
You may be right, as both these fuels were stored in gas cans in my garage for a couple weeks so the ethanol content could have changed.
But since both fuels were stored in the same environment for the same amount of time in the same conditions I would say the 87 vs 93 flame front speed is still valid.
I’ve heard that the higher octane does have fuel stabilizer added so it can be stored longer but I don’t think 2 weeks is enough to degrade the 87 octane to any noticeable degree.
The 93 octane sat out for literally 5 minutes longer than the 87 in the plastic cup during the testing.
Thanks for watching!
I applaud the citizen science. Will this apparatus and method answer the question ?No. But knowledge is built with failure. It took thousands of years to get to Cern.
Ethanol content screws this up. Australia sells little of Ethanol mix, just too bad for engines. Europe sells only 95 or 98 octane but their definition is different. Looking at your 87 residue one can see the reason direct injected engines die earlier from carbonizing.
Thanks for watching!
Regarding the carbon build up, I’m not sure how the pistons look in a DI engine because if fuel residue, but the problem I’ve seen is mainly due to the intake valve no longer having fuel spraying on it, and carbon build up because of the oil in the PCV system. I recommend anyone with a DI engine install a catch can immediately.
Thanks!
The most common fuel octanes are 91, 95 and 98. We use RON
I'm no rocket surgeon but I'm pretty sure you didn't measure the thing you think you did. think high compression gasoline engine vs low compression gas engine vs diesel. octane/cetane (diesel) is a measure of the fuels RESISTANCE of SELF COMBUSTION UNDER PRESSURE AND TEMPERATURE. just my .02$ if you still want to measure the burn speed you could use a engine timing light and a high speed recording and count the frames in-between a complete cycle of ONE cylinder (from tdc to tdc) for each fuel. my theory is that the burn time is insignificant but don't give up on the science! keep going! prove me wrong! ill watch another video of your findings.
Now try it under compression.
regular ol hydrogen will burn the fastest and hotest. Difficult to work with but it packs the most boom.
epic fail by someone who has no idea how to look up the definitions of words.