Cold air intake

Has anyone ever hear that cold air intake filters help gas mileage.

We hear everything here, true and false.

Heard it, but don’t believe it.

It won’t increase power, either.

I did a cold air intake on my Miata. It helps a bit, but quantifiable results are difficult to prove. Be careful of systems with low intakes – they can take in water and hydrolock your engine. They are usually done to improve HP (marginally) not increase fuel mileage as the cost would take quite some time to pay off.


Most cars come from the factory with cold air intake…

I have a homemade CAI on my 93 Caprice using a Cadillac 4.9 air intake, 3" PVC and a K&N cone filter (~$35 in parts). No noticeable improvement in power or mpg, but it sounds good.

When I was having my car dyno tuned, we put a standard paper filter in place of the K&N filter I had on it. The car pulled 3 less RWHP with the paper filter than it did with the K&N. The conditions were the same for each pull; the pulls were about 8-10 minutes apart. It should be noted that the paper filter had seen some use; I reckon it had been used for about 4 months or so. The K&N was new. So it was by no means a scientific test. With that said CAI’s are more effective on some cars than others. For example a CAI really wakes up a 05-up Mustang GT, but on a Toyota Echo, it makes next to no difference at all.

Regardless of the car they will not help fuel mileage.

Here’s why they don’t help mpg - even if they reduce air drag, it’s only at wide open throttle (that’s where you get extra hp on dyno runs), otherwise the throttle is controlling the amount of air entering the engine, if there’s less drag at the intake side upstream of the throttle, you close the throttle a little to let the needed amount of air in.

There are hypermilers out there putting warm air intakes on their engines to save gas. Google it.

I think it’s a wash either way myself.

a CAI does in fact increase power. though only a bit, it does.

mileage, I dont know. if your goal is making more power, I doubt you’ll care about mileage.

It can give you a couple more HP and full throttle. What it definitely does is make your engine much more likely to injest water and hydrolock. Personally, I think they’re just plain stupid.

I’ve heard form techs that Cold air intakes are great at dusting your engine and glazing your cylinder walls. You’ll gain negligible horsepower. Also on some late model cars aftermarket setups will generate check engine lights caused by turbulence that would screwup readings from the MAF. I’ve heard K&N has made revisions to much of its lineup to address the issue for many cars that have that problem, but I don’t know how well they work.

Go ahead and install it if you want to take the risks. You’ll at the very least bling out your engine bay with it.