Cold Air Intakes Mythbusted [Naturally Aspirated]

Cold Air Intakes Mythbusted [Naturally Aspirated]

In this episode of Mighty Car Mods We’ve got the Honda S2000 on the dyno, and we’re going to battle it out. A cold air intake system versus the factory air box Welcome to another episode of Mighty Car Mods proudly supported by Just Car Insurance. Now, cold air intakes Marty, the world is crazy for ’em, aren’t they Yep, they love starting chatter and discussion (and arguments, Marty) and arguments, that’s true. Oh, it’s a really simple mod, so you can understand lots of people do it – all cars need intakes And so you know freeing them up making it flow better get more air into the engine so you can put more fuel and make a bigger bang makes your car go quicker. Now, we have done a video on cold air intakes with turbocharged engines before, that was with an R34 Skyline But today all of you guys have been saying “do a cold air intake myth-busting episode on a naturally aspirated car” and because I’m on the hunt for more power We’ve brought the S2000 down to Haltech and we’re going to battle it out today, so we’ve got a quite expensive Aftermarket cold air intake which came on the car, and then we’ve got our hands on a factory air box So we’re gonna do a couple of runs three power runs on each using the last run because that’s gonna be kind of the most Significant and accurate number, and we’re just gonna see which one makes the most power And that’s the one that we’re gonna leave on the car. A factory air box is often a compromise between packaging, noise suppression and performance. The idea of a cold air intake is that you relocate your air filter away from the engine bay heat And potentially make it flow better, too It’s a commonly held belief that this will make the car develop more power. Colder air is denser So if you add more fuel you get a bigger bang, which means more power. Well, that’s the science anyway But will it work on our Honda in the real world? It’s time to find out So we’re here with Tuning Fork of course who’s our resident expert of all things that go choo choo and bang bang and whistle whistle I have no idea what that means, but of course he’s helping us with our myth-busting today. Now, Tuning Fork, It’s a stock s2000 How much power are we gonna make today like are we gonna make this 35 horsepower that I’ve heard on the Internet? Look, I don’t think so because they do make a lot of power for an aspirated motor But the intake system is… it looks pretty good anyway By putting a pod filter on it or removing all the factory intake system, I don’t think we’re going to make any more power If anything we might lose a little bit of bottom end. Is it true that, I’ve heard some anecdotal Evidence that RX8s with aftermarket intakes are losing power due to the removal of the like highly engineered intake, is that correct? That’s right So on the RX8, because it’s a two-stroke engine [Wankel Rotary], the intake System is critical with the way that it works with the way the air enters, the air speed, So they’ve actually got a really really skinny intake system through a huge resonator mm-hm And what that does is it speeds the air up to get into the two-stroke – if you take all that off and put a pod filter on? You’ve just removed all the engineering so you’ll actually end up losing like low down power Yeah on this car because it’s such a high-tech engine I think that probably will do the same thing, it might lose a little bit of down low Might pick up something up high but the intake system is so big anyway that I highly doubt it. Okay, can we just cover one thing off and that is that one of the kind of, when these arguments happening all over the interballs and and everyone’s like “cold air intake versus this” you know one of the main things that people are always saying is “you put a pod filter on you don’t get more power. The reason you didn’t get more power” They say “is that ECU hasn’t learned that there’s a pod filter on there” the ECU Hasn’t been tuned that there’s more air on there. I mean what? Can we kind of put that to rest yet? We can it’s not really the case because you’ve got a manifold pressure sensor and an airflow meter sensor in or and in some cars As soon as you go to a pod style air flow meter, the ECU knows how much is going in so it uses closed-loop Strategies on the intake sensors and on the exhaust sensors to adjust the tune so, on the dyno, We’ll give it three runs So that’ll put all of that to bed. The third run is the run where the engines heated up. It’s done whatever learning It’s going to do all the trims are in place That’s what it’s going to make. The Honda came with the cold air intake on it when we bought it So we’re doing our first run with it already installed then we’re gonna swap back to the factory setup Because this is such a hotly debated topic we put up a poll on the mighty mods forum and 35% of people Said a cold air intake will make power. 8% of people said it’d lose power and the overwhelming majority of people, 57% in fact, said it won’t do anything I’ve heard some pretty wild claims from resellers of cold air intakes that Promised 10 to 20 percent gains and, while I think it’s highly unlikely that we’re going to make those kind of figures, it’d be Awesome to see some higher numbers. We’ve done two runs and now we’re doing the third run so this is the one that matters So it’s 132.5 kilowatts, so that is the number to beat or to be beaten by? With the factory airbox, we should see this number go down to justify the cost of the cold air intake apart from aesthetics of dampening down the noise of that ah Which is crazy? You can hear at about three and a half thousand rpm. You can hear that resonance in the intake Yeah Which when we’re putting the other box back on we’ll have a look at the resonator the thing that actually takes that noise out of It for a factory car yep And we’ll see that that resonator is actually you know if it’s a restriction And what is doing and if it’s actually affecting the power so, so… people that is the number 132.5 kilowatts at the wheels that is with the aftermarket cold air intake. Now we put the factory system on, who’s excited? I am it’s gonna be amazing And we’ll also just put that in horsepower as well. Oh there it is! So horsepower at the wheels This is the system that came on the car from the factory Including this! Hello! Um, so now we put all this stuff back on See what happens! Because the S2000 has such a high powered naturally aspirated engine a huge amount of development has gone into this intake system This is evident, not just in the cone style filter, but in the whole intake design The factory setup is bulkier and heavier than the aftermarket one which is another consideration when deciding how to modify your intake Manufacturers are trying to keep bugs dirt and water away from the engine. If your intake is dragging through puddles You’re gonna kill your car. Other considerations for car companies are emissions and noise and believe it or not most customers buying new cars Don’t want to hear their VTEC y0 Across all three runs, we’ve lost power compared to the aftermarket cold air intake system So, here are the result, people! We’ve made five kilowatts with the cold air intake system on the s2000. Now, across the board We’ve made around two or three kilowatts. Which is a small game, but up high there’s five kilowatts. Now, I would say for people that are into their choo-chooing snail turbo cars It’s probably not a big difference, but for a naturally aspirated car that’s considerable right? That, to get 5 kilowatts up top I didn’t expect it to make that much power in the top-end Percentage-wise for an aspirated engine that that’s a noticeable gain for not a lot of money. Yeah That’s like 3% or something right an increase So you can see that it did lose a little bit of air speed right down low here When the engines are making around 40 kilowatts. Yeah, it has lost, maybe one kilowatt simply because the air speed has slowed down because Also the air speeds increased, sorry, because the piping diameter has got smaller. It’s more of a tuned intake system at the moment Yeah up top. It’s clearly restriction. It’s picked up like you said 3 to 5 kilowatts The air fuel ratio when we’ve gone back to the factory system has richened up a little bit Showing that there is like a there’s a vacuum in the intake system, so this is well worth doing to the s2000 We’ve also done a cold air intake test on a turbo car and we’ve tested some performance filters on the dyno Which you can check out on our channel. So there you have people! Cold air intake Uhhmmmm… S2000 a little bit more power boom so go get jiggy Enjoy your unicorns follow us on Faceballs of course: Thank you tuning fork ladies and gentlemen And thanks for Martin for coming along because I know he hates the car, but thanks for coming along anyway, man And there it is! Happy days. See ya, peeps! Does that mean it staying? Yeah, leaving it on there That intake? No, no that will not know we’re putting the cold air intake back on there Martin So you think 5 kilowatts is enough to beat me at the drags? Amongst other things, yes But um, like, well. I probably shouldn’t get too much into it now Martin, but you’re actually fired for the next couple of episodes mate We don’t require your services Right… Uh, you’ve made your feelings very clear about the Honda And so you can take a nice little holiday, you can go on a sultana picnic with your mx-5 mates I don’t know what that is, but I’m sure it’s not pleasant And we’ll see you in a couple of episodes time, Marty, so I’ll take the camera now because we don’t need you anymore I’ll see you later Marty!

About the Author: Michael Flood


  1. I live 5 min away from the original site where they filmed Los Pollos Hermanos episode of breaking bad, the restaurant is called Twisters but they still have the original paintings inside and still have a tv playing all the breaking bad episodes

  2. Are any of you big name YouTubers living in a generally hot climate like me? (Florida) it's hot year-round but we get a week of actual winter in December and everything with a gas pedal gets off the line and accelerates faster noticably without modding, soo….

  3. All this video proves is that the stock s2000 intake was engineered very well, leaving little room for improvement. Not the case on a lot of cars.

  4. It's only now I see that aftermarket intakes don't have resonators. It would be interesting to see what a helmholtz resonator on a larger diameter intake could do if you tuned for it. I personally run a 3" intake with velocity stack, with the filter in front of the radiator of my 350z. No short tubes for me lol

  5. How would a cold air intake work on a dyno doesn't the car need to be driving for it to actually work, moving air is colder air

  6. if your car has a standard ass no effort put into janky ass intake then a cold air will not hurt. I bet its like 2 hp tops

  7. You started with a cold air intake to begin with so it stands to reason the car was tuned to take that mod. So when you broke it down back to stock the car is now acting as though it has asthma so of course you're going to lose horsepower. For people looking to this video to see if it's worth purchasing cold air intake for your stock Civics and Toyotas, Camrys and Accords don't waste your time. You're not going to get more horsepower unless you $tune$ the car after you've installed the cold air intake, Ram Air or whatever. You just going to ruin your gas mileage ended up having to pay under the table for a fake inspection sticker.

  8. My cai is right in front of the driver wheel. Whenever I hit a puddle, steam comes out of the exhaust. While I could run a filter bag or water bypass, it makes me laugh that my engine with 220k doesn't hydralock. You Honda boys need tougher motors.

  9. I'm extra glad that I removed and threw away a stock intake, and installed a high performance intake on my ETEC engine. Thank you for the video.

  10. So I love your posts guys don’t get me wrong, but the thing is if installed correctly away from the engine heat it does increase power I couldn’t not with more dense oxygen. Also I’ve yet to here you guys mention to actually get power from them you need to know the basics, must increase flow out of car (headers, high flow cat, catback exhaust), increase burn bigger injectors better spark plugs/ignition packs (my fav E3 dual electrode plugs), and either a piggy back ecu or standalone. Like yes just slapping one on isn’t going to do shit yes but proper and keeping the 3 most important things in mind air, combination, fuel.

  11. This test needs to be done in real world. The in an air conditioned building. I don't drive my car in air conditioned buildings

  12. The factory air box is actually a true cold air intake.  Just install a K&N drop in filter for $35 instead of paying $300 for an intake that just sucks in hot engine compartment air.

  13. I'm only just rewatching through everything and something has been bugging me with this car…

    Why is it 60hp (45kW) down on the claimed stock factory number??
    Even allowing for their figure being at the flywheel and this being at the wheels that's a considerable loss.

  14. Looks like your S2000 is fucked to start with. You're getting 177bhp out of a car that's rated at 240bhp normally. I know you're going to talk about transmission losses but losing 63bhp seems excessive

  15. Honda claims 240 at the crank and here we see 214hp at the crank. Typical S2000, has less power than claimed and it likes drinking oil 🙂 apart of that it's a hell of a roadster, if not the best

  16. The RX8 does not have a 2 stroke engine. The 2 ROTOR 13b rotary engine powering it is most definitely a 4 stroke.

  17. A colder engine runs better and your car is sitting still sucking in hot air where if you were driving it and pulling in cold air you will make a little more horse power.

  18. Why no one tested all these gash aftermarket towing eyes you see on shit box cars you see in supermarkets if a evening normally with because ford stickers down there windscreen

  19. I dont have access to a dyno. I would like to see test results where the air filter is in wheel well, area AND heat insulation the pipe from filter all the way to, say 3 inches after Mas airflow sensor. This is what I've always done when going cold air. What better way to prevent heat soak? I might be wrong. Let's hear you.

  20. 7 hp for 150-200$ and easy to install is great. You should try spending thousands for 30 whp lol that takes a lot more work to install especially on an NA car

  21. This isnt a proper test. The cai works by the car actually moving tho that said a CAI is not going to give you more than 1 hp

  22. talks about sound with a CAI installed, then proceeds to play loud music over the factory intake so you can't compare the noise smh

  23. 4 hp???? What a friggin' waste of time! Especially without looking at and adjusting the fuel trims! Betcha it wouldn't even make that 4 hp over stock IF they ran the car for a few days with the factory set up so the ECU could
    have adjusted. Waste of time "test!"👎👎👎👎👎

  24. An S2000? You guys are kidding yourselves. Either use a V8 or don't bother with this stupid test. You could always redeem yourselves by doing a stage by stage upgrade of a 2010 300c SRT8 with its 6.1 HEMI.

  25. So when you have a car with not a big intake it will do more right? Also is having a better exhaust a good thing or a myth aswell?

  26. You mean the cold air system that grabs all the hot are under your hood? Automotive manufacturers put quite a bit of time in the research and development. I think it's funny some kid would buy a plastic tube with a K&N air filter and think that it was better?

  27. if the ECU works in closed loop and ajusts fuel according to the air mass detected… why the AF ratio is richer with OEM filter?
    My theory would be that under wide open throtle the ECU goes into open loop, with a pre defined injection timing, and that should be reconfigured according to the smaller restriction.
    Does it make sense?

  28. Its on a Dyno… its N/A… clearly it wont give real world performance, the faster you go, the more it matters what air intake you use. rather use a plug in ecu and log the metrics at set speeds, if you have cruise control, even better, use it and gradually accelerate till you hit the desired max rpm and you'll know if it chokes on the high end

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