Do Cold Air Intakes Increase Horsepower?
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- เผยแพร่เมื่อ 11 ก.ย. 2024
- How cold air intakes work. How do cold air intakes increase horsepower? What is the relationship between air temperature and horsepower? This video explains the theory behind cold air intakes.
Note: This video assumes pressure remains constant for all situations, and that air density is strictly dependent on air temperature. This video also assumes air is dry, containing 79% nitrogen and 21% oxygen.
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Not gonna lie, spaced out a bit while u were teaching. Will rewatch the video
Shaun Whitehair Some times I'm monotonous. I make up for it when the cameras are off. :)
Shaun Whitehair Me too dude, I've learned a lot off of these videos and some of them have also helped with my insomnia. It's a win win situation, thanks Engineering Explained!
thought that was just me.
+Shaun Whitehair 3.3%
+SpaceManSpiff 03 That's his plan. More views for him.
I ran a duct from my intake, out through the hood , wrapped it around to the inside of my open drivers window to just in front of my A/C outlet. I blast air conditioning freezing air into it and get 100 extra horsepower
Bingo Bango leems segit
Genius
Bingo Bango holy crap someone tht actually knows wtf he's doin lol
or you install a turbo
Wow. So hows the perpetual motion machine coming along?
I graduated with a BS in mechanical engineering. Most of my videos I've learned myself by reading and watching everything I can find on autos.
💯🙏
I have learned more from watching 10 mins worth of your videos than I learn in a whole 7 hour school day
Lol right? What teachers should actually be doing right here. I took 2 years of auto class in high school and this guy taught me more than any of that.
Ong
They don’t teach you about cars for 7 hours in school. Maybe that’s why genius.
Thats the most ignorant comment of all time
@@TheBanjoShowOfficial in my country where the type of high school i go in, has the option to teach a profession sich as engineering, electronics, medical stuff and more. That might sound good but in reality out of 7 hours (in Wednesdays, where we do only engineering stuff) they took 4 hours to explain how a clutch works.
Best free teacher ever. Need to make myself a plaque!
Feel free to ask questions - I try to make my videos clear to any age group. That said, many things can be confusing if not watched in a particular order, or without pre-existing knowledge. I try to make videos which explain all of the details that work as a system, rather than individual videos that repeat information. Let me know what questions you have, and I'll try my best to help.
Yes, the volume remains the same. All I'm saying is that 4 liters of air at 300K has the same amount of oxygen as 4.13 liters of air at 310K (with the given assumptions). Thus, 10 degrees equates to 3.3% more air.
Just confused. Aren’t we supposed to feed cold air not hot air, hence the cold air intake system. But based on your ideal gas eqtn, you actually heated the air by 10C not cooled. 310k -273 is 37C.
Volume sir is not MASS.
Great video however, keep in mind I have to take off my boots just to count to 20.
Underrated comment
As mentioned before, the automotive engineerings who design the air intake system do a good job at designing the intake system to meet their goals. However squeezing hp out of the engine is rarely their goal. In most modern application emmison rules drive a large majority of the design. Another large concern is sound level. Even performance cars have fairly low intake noise. Therefore, cold air intakes increase horsepower by changing the design to focus solely on performance. Some of these gains are from decrease charge temp and others are from improved flow characteristics.
you are well spoken and clear, I just stumbled on your site. nice work!
It is a shame that most kids that put these on their engines have them installed to pull in under hood temp air. Completely defeating the purpose of it.
***** I think you are referring to an intercooler which is different. An intercooler is designed to lower the intake charge after it has been heated by forced induction.
@@walkerscranger No, I think ScannerDanner is actually referring to removing the stock air filter system and replacing with a cold air system. Putting an open air filter inside the engine compartment without getting outside air will use air in the engine compartment. That air will eventually warm up and expand.
@@MrHarr0073 The person I was referring to has been deleted or remove their comment. I was not replying to Scanner Danner, it was some @***** person. I teach automotive classes at a technical college and I see tons of students doing this misleading addition to their vehicles. I tell them there is no such thing as cold air going into the intake... only ambient air if it is picked up outside of the engine compartment. Yes, the market calls it "Cold Air Intake" but like anything else people take it literally without investigating.
I tried to keep it pretty simple, it's always good to learn new things my friend!
for Honda guys, instead of putting the metal tube for a cai, or short ram, just get a factory type r intake tube. it has smooth walls and radius. don't let the outside fool you, it flows very good, then just put your cone filter on it, and get fresh air from outside of the engine bay, then get rid of the lower portion of the air box because it's very restrictive, and you lose a bit of unneeded weight too. for added smoothing of the air, get a velocity stack, they aren't heavy, and it helps smooth out the air
Rain water shouldn't be too much of a problem, but if you were to ever run over a puddle or get into decently deep water, you could risk hydrolocking your engine - filling the cylinder with water and then braking the weakest link, usually the connecting rod.
It might suck up a curious kitten and you'll get a cat-back exhaust.
Most of the restriction is the paper filter element and tiny stock snorkel intake opening. For manufacturers paper elements are cheaper, and the small inlet opening to the air box is in the interest of quietness. So if you use a wide-open high flow filter located in a separate cool part of the engine bay you can get a 5-10% power increase and a racy intake howl when the revs get up. Cooler air is denser and contains more oxygen.
Haha me too! Glad you enjoy the videos and learn from them!
Yes, they have an excellent video on the subject, hence I tried to take a different approach.
Ultimately I would say most are pointless unless the factory tubing is restrictive - I would guess that the vast majority are not restrictive, and that the only "positive" (for a car guy) effect of a SRI would be a louder engine - but this is simply because the silencer box has been removed. They may be of more value once the engine is more heavily modified and requires more air - possibly.
Lies! I checked your channel, you've been subscribed for a month. Cheers
Basically, pick whichever you would like. Based on what I discussed in the video: 10 degrees cooler = 3.3% more power; 10 degrees warmer = 3.3% less power.
Theoretically it could increase fuel economy if thermal efficiency was improved with more oxygen burning, but the opposite could hold true as well.
You're very welcome, thanks for watching!
I love running my car in the winter at night! My engine temp stays at around 200 degrees and it pulls strong all night long. When that California heat kicks in, I don't even bother because 2-3 pulls at WOT and my engine temp creeps up to 225! And immediately I can feel my power drop off! So yes, your deduction is correct. A sports car, and actually, any car, will perform better in the cold because it is getting cold dense air!
It just feels better and fuller to breathe cold air over hot air in general.
they normally do not workas well as they say they do. a buddy of mine did test on a Dino and found some awesome results. (5 runs each filter. giving you the average) he started with a cheap frame air filter, 208 HP. next he used a K&N high flow high filter, 215.5 HP. took out the stock air box and installed a cold air intake made by K&N, 215 HP
Toyota Tacoma
So a high flow air filter did the same as a cold air intake?
@@StoicOutlaw17 A stock air box will almost always provide colder air and better airflow than an aftermarket intake. It is only recommended to buy an aftermarket intake when an intake that houses the filter and MAF/MAP sensor is not present. A K&N stock filter replacement will flow just as much air as any pod filter. So if you have the stock air box and the engine is N/A then spend $50 instead of $200.
From experience, there is a difference that you can feel with a cold air intake. My friend and I made one with a simple aluminium plate... because his air filter (pod filter) was simply clamped on the stock hose. By lengthening the hose and isolating the filter, we were able to feel a surprising difference in engine power. It feels more willing than before.
Only true if its a vehicle with no ecu
Same here ! I added a CAI and me and everyone that has drivin my car can feel the difference in the throttle response ! Mind you I had a brand new filter on my stock oem intake
I studied engineering & don’t understand any of these formulas. But is a True engineer. Great video!
A large portion of the advantage you forgot to explain was the fact that most cars have a intake that has a bend, and usually narrows out. Cold air intakes have usually no bends and larger piping leading to the manifold, which increases the breathing properties of the engine
no, real CAI are down near the ground and usually have a way to cut a hole in the bumper to force air into the intake directly, RAM intake.
It's basically the volume of the engine (the amount of space displaced by the pistons). Check out my video on engines. Obviously larger engines have the potential for more power, but you want to size the engine based on what you want the vehicle to achieve (high power vs good fuel economy, etc.).
It's good to see you still posting videos. I have learned a lot thanks man.
If you were to assume that the density of oxygen in air remains the same, as well as the air pressure, then yes. But that's not necessarily true. But there is likely a difference between driving mid-day and at night. Probably small though.
Not gonna lie all I wanted was a yes or no
In my experience, every car is different but on most Japanese cars if the filter is in a place where it can get enough air and isn't to close to the engine sucking up to much hot air them, yes they do make more power at high RPMs.
What are you going to retune? The engine can calibrate A/F ratio accordingly based on how much air is coming in, as well as using an oxygen sensor to close the loop. It should be a fairly automatic process.
Glad to hear it, thank you!
Thanks for subscribing, cheers!
Great video, you missed the other key advantage of a CAI, other than the cold part. Velocity, you can change the velocity of the air going into the motor allowing for increased volumetric efficiency, why a SRI doesn't gain power is not only because of the fact that it's taking in hot air, it also has no way to create velocity since most are 6" in total length, instead you gain throttle response. With a CAI you can change length to increase velocity while balancing it with throttle response.
Finally!! Someone else who understands this concept.
The louder roar is primarily because the silencer box around the air filter was removed, assuming your stock engine had a silencer box. Most do, as a lot of people don't like loud engines, and regulations may require it. It's nice to hear them breathe though!
He understands it, I don't . I did find it strangely fascinating. Well done !
Your videos are GREAT! You have all your information prepared so you don't "uuumm" and pause at all, keeps it interesting. Good work, thanks for the videos!
Depends on altitude and temperature on hw ur gains are. Take a car from sea level and go to the mountains then ull see the difference. Cai help alot. More air for ur gas which means more horsepower.
Thanks for subscribing!
Thanks, please do!
Hi Engineering Explained, i think you are familiar with the formula P1 multiplied by V1 = P2 multiplied by V2 ( or P1V1=P2V2 ),
(1) when a car is not moving & its engine is idling, at a single instance in time; air available for combustion is directly proportional to its volume x pressure ( & inversely proportional to its temperature ), If there is an air filter installed by the car manufacturer, air available (for combustion) will also be constrained by volume of the box housing the air filter.
(2) supposing a circular (10cm radius) snorkel is installed - protruding above engine bonnet, if the car is moving at 120 km/hr.(or 33m/sec), volume of air entering snorkel in 1 second =cross sectional area of snorkel x 33 m/sec (3.14 x 0.1m. squared x 33 m/sec = 10.362 cubic metres ).
(3) by comparing the condition of the air when car is not moving (P1 x V1) with condition of air when car is moving at 33m/sec., where the volume of air entering snorkel (within 1 second) is 10.362 cubic metres, it can be seen that V2 is 10.362x more than V1. ( let's ignore rotational speed of the engine at idling compared to moving the car at 33m/sec. ).
My point - by simply installing an intake tube or a snorkel into a fresh air stream ( NOT inside the engine bay), there is a 10x increase in volume of air available for combustion.And if a larger diameter conical funnel is installed at the open end of the intake tube, the volume of air available is increased further.
That - a snorkel, is a far more sensible means of increasing engine power than installing some fancy sports air filter inside the engine bay.
Any problem/dispute with my calculations?
@ralderhali cold air is denser than warm air. Being denser means the same volume of air has more oxygen to burn thus making more power
What you are essentially doing is trying to increase your efficiency.
The maximum efficiency is stated by the carnot cycle: n = 1 - (T1/T2). where T1 is the lowest temperature in your cycle and T2 is the hottest. Note that this is a ideal cycle but it does say you can increase the efficiency by decreasing the lowest temperature in your cycle
Same amount of air by volume taken in, more air by mass since it's more dense. You are correct.
In the summer months on a normally aspirated car and indeed a twin turbo charged car I once owned I noticed a decrease in power compared to cooler times of year. That being said, summer evenings seemed better than summer days.
On almost any combustion engine, more (and colder) air in, and more air out = more power!
Man, you broke it down though!
Nice.
Came looking for an explanation. Got stinking chemistry lesson.
It may not produce much more power, or at all, but my CAI made my econo box turbo sound so much better. Burbly on the throttle and blow-off during gear changes.
I simply explained the logic hear. It's very likely that many times you won't gain anything. It's important to find (or create) good data showing the improvement.
I love it, its oil burning tendencies and all. :)
Hi, sorry I forgot to mention the significance of the Box housing the air filter in paragraph (1),
Assuming the car is moving at 33m/sec., the snorkel will be channeling fresh air into the air Box. If V2 (volume of air when car is moving) is 10.362 x more than V1 (volume of air when car is not moving), and since V1 and V2 are both constrained to travel thru the volumetric space of the air Box, when V2 would be forced to be equal to V1 (the volume of the air Box), P2 would be 10.362x more than P1.
Thus the snorkel would perform the same function as a light pressure turbo-charger that would increase the pressure of air by a factor of 10.362 ).
But of course, the factor of 10.362 is based on the assumption that the snorkel is capable of perfectly sucking 10.362 cubic metres of air when the car is moving at 33m/sec.
I tried it on my Toyota Camry (2.4 litre engine) and the Camry out-accelerates a BMW (2.5 litres engine) from 100km/hr. to 220 km/hr. - taken at a huge risk to my Driving Licence.
What parameter would you change in order to make the most of a CAI? Shouldn't the ECU know when there is more oxygen present?
You are correct.
Will trade for STI.
You’re not gonna say whether or not they increase horsepower but the title is do they increase horsepower
Awesome, thanks for sharing!
better to use stock system and just connect a hose from your cabin AC under dash box to your air engine intakes before the filters of course for a true cold air intake...cheaper too
1.63-2% sounds very specific. Care to clarify your claim? I'm not stating that a CAI will increase your engine's HP by 3%. I'm claiming that if an engine receives the the same air, at 300K vs 310K, it will have 3% more oxygen to burn.
I have a CAI on my tiburon and it made a slight improvement to performance, I got a very noticable improvement when I added a 421 header and cat back exhaust with it. So they do make difference but by themselves I would say they add 3−6 hp
Just to clarify, CAI allow for denser air, wich means more mass of air because its colder air. Colder things are denser things, but 1Liter of Air at 80C has the same volume of 1Liter of Air at 20C
Yeah, I didn't know it has called that. But I'd rather do without t. It may get stack in the "warm air input" state at anytime (especially in "retro" cars like mine)
I believe you mean large bore vs large stroke, displacement remaining the same. Likely longer stroke would ultimately give more torque, but with a smaller stroke you can typically rev higher, thus creating more power. That said, there could certainly be engines which do the reverse of what is typical.
Honestly. When I installed my intake system. I obviously felt a difference in throttle response, took the car out stock and then took it out with the intake, I ran people with it and then ran them without it, the difference was major, the people who were smoking me, I was able to close the gap of 4 cars to half a car with just a intake and a vacuum hose
A cold air intake does not only reduce interior intake tempratures which helps create horsepower, but cold air intakes (the one i use anyway) have larger volumes of air that go into the engine, my stock intake i had was at least twice as small as the cold air intake i have on now, in wich the engine can put more gas into the air mixture, in a dyno i received 30 more horsepower and 27 more torque,
Nope, North Carolina. But I might live in Oregon.
Probably so, yes. Check your electrical system as well, plugs/wires/distributor. Obviously if there's a check engine light that would help.
They work pretty well, and it's also good for your engine and reduces emissions.
HOWEVER I would pay attention to how low to the ground the intake is, especially when driving in heavy rain.
If you suck water into your engine it will blow the engine, water is about 3 times as dense as air, so basically triple the pressure in the engine and imagine what would happen. I put an intake in my camaro, but I didn't put it in the bumper because I live in El Paso where flash floods are a yearly thing.
Finally. Someone that deserves the amount of subs he has. Great video brother. 10/10 explanation.
I was just driving in the polar vortex here in the Midwest with -20 f before wind-chill and my ait was -5f and my car didn't feel noticably faster, after that experience I won't bother with a cai again, but they can make ur car sound nice.
I just visited your website. You have good lessons on there! I'm an IT guy so I mostly tinker with electronics of that nature but I really enjoy learning all you share about cars almost as much as I enjoy learning about IT.
Fortunately, I only had to take 1 chemistry class (hence I really don't know what I'm talking about chem-wise). If I can't see it I don't like it. Much respect to ChemE, ElecE, and CompE majors, I could never.
Your application of the ideal gas law is correct but the fine details are not. V (volume) is not the independent variable, it is n, the molar flow rate of air into the engine. Each intake stroke of an ICE takes in the same volume of air. At cooler temperatures, the density of the intake air (n/V) is higher than at higher temperatures. Consider an engine running at 3000 rpm. It is sucking in a constant volume of air. If there are more moles of O2 in this constant volume, more fuel can be injected leading to more power.
You are correct and wise in sidestepping the effectiveness of cold air intakes. The most good they do is to fatten the wallets of the manufacturers. All the air that comes into a car's intake is from outside the vehicle. The flowrate is large. It is neigh impossible for this volume of air to pick up any appreciable heat from within the engine compartment. The air is moving just too fast.
A young engineering explained
Jason, and because it likely wouldn't do anything. Perhaps one day.
The decrease in air temperature caused a kind of natural supercharging. As air cools down, it's molecules become less energetic and so it's density increases.this means that the same cylinder volume will contain a little bit more air, and a little bit more fuel to go with it. So the quantity of charge that is compressed and ignited in the cylinder goes up.
You could just leave it as is, or some make splash guards for the filter to prevent any issues.
My buddy's got the same Acura, he took out his headlight and converted it to a ram-air style intake :p
Yes, I guess I wasn't completely clear on the analogy. All I'm saying is that 4 liters of air at 300K has the same amount of oxygen as 4.13 liters of air at 310K (with the given assumptions). Thus, 10 degrees equates to 3.3% more air.
Yes, more air means more fuel thus a more powerful power stroke.
In the case of my truck all i had to do was simply remove the two rubber hoses going to the intake and run a straight peice of hose to the fitting on the heater hose and the other end to the end where it connected right above the thermostat as a bypass. But like you said it can be as difficult as replacing the whole intake or more just to bypass such a simple system that robs power when its needed for racing purposes.
Perhaps, though turbochargers typically have intercoolers to cool the intake charge.
It acts as feedback to close the loop on the system. If there is oxygen left over, the ECU adjusts accordingly.
Thanks for sharing your wisdom.
Strangely due to your approach I understood the math. And I understand the logic.
One thing though that people dont instantly realise is. More horse power mods you do the more petrol you use. People think that you can get more horse power from mods using the same amount of petrol. Which simply is incorrect.
I basically put a 7 inch air intake in my car. The maf read more air in so it put more petrol in 😵
I was able to watch my fuel gauge move literally in front of my eyes.
So...
I reversed my mod and then put a cover over half my air intake just before the filter and now I'm saving petrol coz the maf sensor has less air over it. So it puts less petrol into the mix.
I'm no mechanic I just thought it was obvious to do that.
For the absolute auto newbie, such videos are a great watch, and we often send them to our fans to share with their friends to get an idea about how cold air intakes amp up car performance.
Thanks for watching and sharing!
Most setups have the supercharger run below a certain rpm which gets decoupled from the engine using a magnetic clutch once the turbo is making boost. The other way of doing it is to have a bypass valve that opens up and just lets the supercharger move air freely while the turbo forces it into the motor. These are less efficient since the engine is still putting power towards spinning the turbo resulting in parasitic losses depending on the size of the unit.
I have a master's degree in mechanical engineering from Stanford. I appreciate videos like this. In the vehicke mod workd, there are tons of idiots out there. Uve seen many videos saying CAIs actually refuce power. Did the moron who installed it reflasg the engine control module per the instructions? If he ibstalled it hinsekf, probably not. The difference in air flow ti the engine in my 2011 Xterra Pro-4X, with a K&N CAI, vs the stock air filter bix, is very substantial.
Cold air is more dense, assuming pressure hasn't changed (this video shows that relationship). But at sea level you'll have more air (from higher pressure) than up in a mountain, which would obviously be colder.
Ha, that's directly converting 10 Celsius as in 10 degrees above freezing. Incrementally, 10 deg. celcius warmer would be about 18 deg Fahrenheit warmer.
You have a Teg!
lucky you. my dad had a Teg, but we had to scrap since it was over 15 years old with near 300,000 kilometers on it.
if we didn't scrap it i would be driving it today.
Integras are epic cars :D
this thermodynamic approach applies to enclosed systems only with two states, like inside the combustion chamber before and after piston compression . The topic Needs more assumptions and correct approach. Heat Transfer theories must apply too, I am not convinced, it's more complicated than this brother.
99, sorry for your loss!
just an fyi for anyone considering going with a cold air intake system, the factory intake location is all ready at the coldest location on anything built in the last 20 years. the filters that come with these aftermarket systems do more damage than good.
No. Depends on manufacturer.
I believe EcoBoost just means turbocharged and direct injection. Allows for more power in a smaller more efficient package.
Not exactly sure; could be EGR or just a way to heat the engine up. Warm engines are more efficient.
Very simply, if the cold air intake can get air that colder than before the modification into the engine, then you'll get more power out of the engine. This is because the colder air means it's more dense, and hence has more air molecules. Rather like supercharging, or turbocharging, forcing more air into the engine cylinders.
Ah, yes, I understand how twin-turbos work and twin-scrolls and sequential turbos and all that, but the idea of a supercharger + a turbo hurts my head, and you're great at explaining this stuff! Keep up the good work too, my friend. :)
I intentionally did it the way I did it in the video. All I was saying was 4 liters of air at 300K has the same amount of oxygen as 4.13 liters of air at 310K, assuming the gas percentages remain constant.
The air temp shouldn't matter as long as it's consistent with the test from each. Yes, you should have a good fan.