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As I have been saying for years, warm air inlets are better for road cars, cold air is for race cars. I can confirm that that there is not a single ounce of truth behind that Id like to see that proof, i have seen back to back dyno results from testing on cold/warm air feeds on three different engines (one of them my 24v Cortina) cold air gives more power at what, warm air gives better mpg and better throttle response throughout the engines midrange, where you need it for a road car.
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Volvo back as my main squeeze, more boost and some interior goodies on the way.
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I appear to not have my RR graphs handy, but heres some info thats relevant, although i admit this particular guy did not see large gains in MPG, we worked out taking the warm air from above the exhaust manifold on my 24v was worth about 4mpg at 60mph and throtle response was improved according to the computer. www.metrompg.com/posts/wai-test.htm
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Volvo back as my main squeeze, more boost and some interior goodies on the way.
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Colonelk
Posted a lot
Posts: 3,740
Club RR Member Number: 83
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1959 OPEL P1 376MPG!!Colonelk
@colonelk
Club Retro Rides Member 83
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All the petrol guys on ecomodder.com hook up warm air intakes, cant remember the theory behind it but it does improve MPGz at the cost of power obviously. Yeah this is a cool car, the whole pre-vapourised fuel thing is supposed to help a lot but I don't know about the practicalities of how well it works with road going cars be an interesting project though!haha
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I can confirm that that there is not a single ounce of truth behind that Id like to see that proof, I have seen back to back dyno results from testing on cold/warm air feeds on three different engines (one of them my 24v Cortina) cold air gives more power at what, warm air gives better mpg and better throttle response throughout the engines midrange, where you need it for a road car. Warm air gives better MPG because you have reduced the amount of fuel going into the engine (assuming your car is fuel injected and compensating for mass). This also reduces power, and therefore efficiency. It does also reduce thermal losses to the exhaust slightly but looking at my results from an experiment we did at uni, it wouldn't be enough to cause any noticable difference until air temperature reaches sort of 100deg C, and even then it would almost be negligible. Any other differences are to do with your engine setup and could be changed to better suit cold air.
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1997 TVR Chimaera 2009 Westfield Megabusa
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P.S. with the ram air analogy, the reason they aren't fitted to tourers is that they don't reach high enough speeds to have any effect. In fact, no bike ever does really so its a bit of a farce. Mostly there on the very top end sports bikes for superbike homologation purposes, or so i have been told.
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1997 TVR Chimaera 2009 Westfield Megabusa
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My 24v was on a live map at the time and was being adjusted for best results to suit the inlet charge temps, less power is not less efficient if maximum power is not your main aim, which it shouldn't be on a road car, using less fuel and having a more responsive engine in the most used rev range is far more important, mine would still spin the wheels in third gear if the road was damp, but was managing to average 30mpg, not bad for a 2.9 V6 in a square car.
If you want max power then cold air is fine, but as you say you need more fuel to cope with it, i'd rather sacrifice a few BHP and have the car cheaper to run and nicer to drive the 95% of the time its not running wide open throttle.
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Volvo back as my main squeeze, more boost and some interior goodies on the way.
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I think you'll find that cold air is always better.... in terms of efficiency. The only perceived economy comes from the reduced oxygen content of warmer air and therefore less fuel requirement to get a stoichiometric ratio. You could get the same mpg in the same way out of your 24v by fitting a smaller throttle body and using colder air.
Not saying you don't get better mpg out of the hot air, but really it is simply a "trick" as it were. In reality it just validates that you ought to be using a smaller engine more efficiently for the same power/economy. Though realistically when there is only a discrete selection of engines to pick from and you have specific needs then tuning this way definitely would help you make a larger engine more driveable as a daily.
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Last Edit: Feb 2, 2011 16:04:47 GMT by jasonb360
- '80 Mk1 Vauxhall Cavalier Saloon, 3.0l 12v... in progress with some special plans ahead - '94 106 Rallye, Endurance Rally Car
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I think you'll find that cold air is always better.... in terms of efficiency. The only perceived economy comes from the reduced oxygen content of warmer air and therefore less fuel requirement to get a stoichiometric ratio. You could get the same mpg in the same way out of your 24v by fitting a smaller throttle body and using colder air. Not saying you don't get better mpg out of the hot air, but really it is simply a "trick" as it were. In reality it just validates that you ought to be using a smaller engine more efficiently for the same power/economy. Though realistically when there is only a discrete selection of engines to pick from and you have specific needs then tuning this way definitely would help you make a larger engine more driveable as a daily. Much more eloquently described ;D
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1997 TVR Chimaera 2009 Westfield Megabusa
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point taken, and worth bearing in mind for those people that do just bolt on a cold (or warm) air feed on a stock engine.
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Volvo back as my main squeeze, more boost and some interior goodies on the way.
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don't take it as criticism though, I'm very glad someone champions dyno proven observations from personal experience that flies in the face of common misconception! - if it wasn't for you mentioning it with some weight of experience or evidence then it wouldn't get discussed and everyone would keep trying to put cold ram air induction kits on their dailies not necessarily gaining what they wanted lowriderlorel, thanks!
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- '80 Mk1 Vauxhall Cavalier Saloon, 3.0l 12v... in progress with some special plans ahead - '94 106 Rallye, Endurance Rally Car
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