WAI and detonation.

[bigsyke]

So ive been reading around for a while here, and I now want to ask;

Does a Warm air intake actually make the engine more efficient? I personally will throw these variables out there.

The throttle position sensor has a preset range( say 0.4 of range compensated by the o2 sensor, or MAF sensor). Then with the extra throttle plate open,Manifold vacuum is down, thus the FPR load increases. Doesnt this throw off the ECM readings? What about an engine with a MAP sensor?

Or the MPG destroyer, the Knock sensor - on some vehicles the ECM dumps insane amounts of fuel into the mix, and retards the ignition timing by 3*. The knock sensor could possibly be tripped with the warmer intake charge durring summer. I know alot of cars dont even throw a CEL for a Knock sensor, but couldnt the same or better gain in mileage be had by simply using a cold air intake, and advancing the ignition timing by *3 degrees or so?

Which one would yield higher gains? I think personaly im going to WAI in the winter, and CAI with advanced ignition timing in for the summer.

[Dr. Jerryrigger]

Sort answer; maybe
long answer; very little if at all, but it can make your vehicle more efficient. Hot air is less dense so it takes less fuel to detonate in the way your O2 sensor wants to see. So essentially it's like having a smaller engine. Modern engines are designed to work at various temps, with some limits. If you can keep it up near the high limit year round your going to save fuel. I've hear over 180F could be a problem, and i don't doubt it. For best results having seasonal or adjustable intakes, would give the best results. If a WAI will take in 170F air on a 25F day, a 95F day would be bad news. or if it was taking in 170F air on a 95F day, it would be rather low on a 25F day.

[dkjones96]

The ECM can usually compensate. In a mass flow EFI system the less dense the air is(such as hot air) the less the sensor reads so the less fuel gets injected. In a speed density EFI system the TPS and MAP will read more open and less vacuum but the computer uses the IAT(intake air temp) reading to calculate the offset for air density, further correcting for the hot air. Also remember the O2 sensor is in there.

There is no benefit to running colder air and more timing advance when it comes to fuel economy. Power? Heck yeah! But one of the things about engine optimization is getting the spark as close to TDC while still having peak cylinder pressure around 10 deg ATDC. If you advance timing you increase the amount of time between spark and 10 deg ATDC thus creating more waste between those two events.