Do K&N air filters increase gas mileage??

[XS650]

quote:

---

Originally posted by Boeing 757 Pilot:
Hello Guys,
I was wondering if anybody had any noticeable gas mileage increase when using a K&N air filter?? I have one on my Z06 Vette and haven't noticed any increase while driving on a 750 mile road trip. How much horsepower will they make compaired to a paper air filter???

---

I expect than reported gas mileage improvements with K&Ns on modern computer controled engines are placebo effects. The engine management system maintains design fuel mixture over a wide range of inlet conditions so small changes in inlet restriction should have no measurable effect of fuel economy.

How much extra power is a function of how restitive your stock element was. Late model Corvette air filters tend to be big and any improvement over a clean paper filter would be so small as to be difficult to measure.

 

[Horatio]

At the time I thought I found a 5% increase in mileage with my Civic. Now I'm not so sure if I calculated things properly and I'm thinking about going back to paper anyway (except it seems hard to find anything but Fram in this city!).

I can send you my Excel file of nearly every single fueling of our car if you like (I have 120,000 of 130,000 kms accounted for....lost the other bills somehow; kinda po'ed).

Greg

 

[Boeing 757 Pilot]

Hello Guys,
I was wondering if anybody had any noticeable gas mileage increase when using a K&N air filter?? I have one on my Z06 Vette and haven't noticed any increase while driving on a 750 mile road trip. How much horsepower will they make compaired to a paper air filter???

 

[Rand]

the K&N lets through more dirt and not much more air because the filter isnt a restriction (unless you let your paper filter get really dirty) Also unless you are at WOT the restriction is the throttle.

Its worth probably 1-5 hp (5hp being vs a very dirty paper filter)

Just my opinion.
Also if your car starts running different you might have to clean the MAF sensor. It takes about 5min and a 3$ bottle of cleaner to do.. no big deal. The oil may migrate from the filter to the maf wire.(it did on my tbird) It seems the filters are way overoiled when they are new.
Rand

 

[Ken2]

How can an air filter element affect air flow during normal driving?

A gasoline engine has a huge restriction in the air intake called the throttle...or butterfly, or whatever you call it. At any position except wide open, it does it's job of restricting air flow.

So, unless you're always driving wide open throttle (which I haven't done since I sold my VW bug many years ago) the air flow through the filter is meaningless.


Ken

 

[JohnnyO]

I have one in my Ranger, I don't think it made any difference.

 

[XS650]

quote:

---

Originally posted by Ken2:
How can an air filter element affect air flow during normal driving?

A gasoline engine has a huge restriction in the air intake called the throttle...or butterfly, or whatever you call it. At any position except wide open, it does it's job of restricting air flow.

Ken

---

Good question. Even at full throttle the whole rating system for aftermarket air cleaner elements is nonsense. Without knowing if the stock air cleaner element is a significant part of intake resistance or not, airflow ratings are meaningless.

 

[JohnnyO]

I think a 502 big-block is one thing, a modern 2.5 to 4.0 street engine it won't matter. I like it because it's easier to clean it after off-roading than to keep buying new ones.

 

[Bamaro]

Filters like K&N mainly effect WOT performance.

 

[XS650]

quote:

---

Originally posted by Bamaro:
Filters like K&N mainly effect WOT performance.

---

And sometimes not even that.

 

[trey]

so i'm do for a filter change soon, is a K&N even worth it for my 03 maxima?

 

[Ken2]

Nope.


Ken

 

[ekpolk]

quote:

---

Originally posted by Ken2:
How can an air filter element affect air flow during normal driving?

A gasoline engine has a huge restriction in the air intake called the throttle...or butterfly, or whatever you call it. At any position except wide open, it does it's job of restricting air flow.

So, unless you're always driving wide open throttle (which I haven't done since I sold my VW bug many years ago) the air flow through the filter is meaningless.


Ken

---

I wouldn't bother with a K&N either, for two reasons. First, I've heard some scary things about what they do let through. Second, I tried one on a 1998 Buick Regal GS (the supercharged version) and couldn't detect a difference in either mileage or performance (by butt-o-meter, no dyno). I didn't do much WOT with that car because in a matter of seconds, I'd be at orbital escape velocity. . .

That said, there may at least be a theoretical advantage with the lower restriction filter. The engine is required to expend a certain amount of energy to move air through the filter, regardless of throttle position. So with a low-restr filter, the engine's ECU is probably throttling down just a tiny tad to maintain any given output as compared to what it would have done with a filter that required it to work a little harder to breathe. Now whether any mere mortal could actually feel this difference is another matter.