Question for all of you.

My friend has a 01-02 VW GTI and has had a Cold Air Intake on the vehicle for some time now. He mentioned to me that he experienced a 30% INCREASE in MPG from mid to high 20's (usually 26-28) to 30-33 MPG. Does this make sense? I always thought, mostly due to the people I know who have done modifications to their vehicles, that it always resulted in a DECREASE (not a large decrease) in MPG.

If this is so, I may highly consider doing this.

BTW, would it matter if the vehicle was 6-Speed AT (he has a 5-Speed MT).

Thanks!

 

Too many factors to say that there would be an increase just because of a CAI. He could've kept his foot out of it and getting 30-33MPG isn't difficult out of a VW GTI. I once got 36MPG out of my 93 GTi 16v, no mods at all. I got 40MPG out of my wife's 01 Civic EX on a trip; no mods.

 

your friend is full of shit.

 

Quite possible. I did not say much after he said this as I had always heard of the decrease.

That is why I came to all of you hoping to hear some results from those who have had a CAI put in their vehicles (MPG before vs MPG after).

 

I think that most people experience a decrease in MPG when they have a CAI because they tend to get a heavier foot.

 

Here is some information from K&N's website:

1. How much of an increase in miles per gallon should I see from using a K&N air filter or intake kit (Fuel Injection Performance Kit – FIPK, Typhoon, 77 Series, 57i, or AirCharger)?

Results will vary depending on your vehicle, driving habits, load on the engine (towing for example), existing air system restriction, and other factors. Many K&N users report an increase in miles per gallon. See our testimonial page. K&N air filters and intake kits provide less restriction on your engine’s air intake than typical original equipment manufacturer (OEM) filters and air box systems. Less restriction can provide for more efficient combustion. Our internal testing is performed using employee and customer vehicles. We usually have the cars for a short period of time that will only allow for fit checks and dyno (power curve) testing. If you take advantage of added power by driving harder, you will not see much of a gain, if any, in MPG. Also if you add a K&N filter and the primary source of air restriction in the OEM system is the air box, you won’t see much of a difference in power or MPG unless you add a K&N intake kit to reduce the restriction.

Cliffnotes: An aftermarket intake will increase your MPG because it allows the engine to breathe easier and therefore there is less load on the engine. Consequently fuel consumption is improved. But as was said, many times a person who mods his vehicle will now go WOT more often than before and therefore there is a decrease in MPG. Your friend could have improved gas mileage but I highly doubt a 30% increase.

 

I know that in my 1991 Integra, when I had it, I took the bottom half of the airbox off and removed the resonator. This allowed for much more air to pass through the filter and the air tube (and consequentially to the engine). My MPG went up about 10-20% from this, consistently. The OEM air box and resonator and inlet tube are really restrictive on that car. On the TSX, not nearly as much I'd think.

 

I do agree as it sounded a BIT too high.. Maybe 10-20% as many users are reporting.

Thanks for all of the information fellas

 

So I am full of shit?

Ok I have a 2k3 VW GTI 1.8T 5 speed. I drive close to 25k to 30k miles a year. I know my car quite well. Before I installed my intake I was getting about 275 to 300 miles to a tank. At 40K I installed my intake and now I get between 350 to 360 miles a tank. Now I have a 14 gallon tank and I drive a combonation of city and highway about 40/60 split.

Now on my 2000 Nissan Sentra with the SR20DE engine the CAI didn't change the gas mileage that much. It gave it a little more punch, but gas mileage stayed about the same.

One thing MrChaos didn't think about was the difference between NA engines and Turbo or Supercharged engines. Forced Induced engines tend to respond to intakes differently then NA engines.

 

there is no way you can get 30% in fuel efficiency with an after market intake... if this was the case, the manufactures would simply add bigger intake and use it for marketing.

5-10% maybe, 30% when pigs fly..

 

I think it has more to do with the mileage of the engine, as the engine loosens up a little with more mileage. My old AE86 was getter better mileage than it was new and higher than the factory's claim. The added CAI could be coincidental for the mileage increase but it will help with power. There's a good possibility you will get the same mileage if you reinstalled the factory intake.

 

Maybe he put one of these in his intake.
Sorry, I had to. I'll go away now.