K&N

JIMNLIN wrote:

d1h wrote:
Who has replaced their stock air filter with a K&N? Are they really better? Improve performance, gas mileage, etc.

I doubt in many of those responding speak from actual experience with the product.

Improve performance ?

Improve gas mileage ??

I've used a K&N OEM drop in replacement filters over the years with no issues on gas and diesel engines. The last gas powered truck with a K&N drop in OEM type ran for over 230k miles with no issues (same cleanable/reusable filter).
Never noticed any mpg gain but the truck did have a bit more more seat of the pants improvement while towing which helped the engine run a little easier while towing.

I use a older AFE pro 7 filter on the on my '03 Cummins since it was new. No issues in 255k miles.
Never noticed a fuel mileage gain but it did drop the Cummins EGT around 100 degrees while towing. I would see 1300 degrees temps on the Westach before and 1200 degree max after installing the Pro 7.

Will the K&E do anything for your tow vehicle ?? Can't say as its gonna' depend on the tow vehicle.

I HAVE USED a K&N so I do have experience with a K&N

Used in in a FI engine.

Did it "improve" performance.. NO. Not one bit..

Did it "improve gas mileage.. NO. Not one bit..

Did it foul my MAF.. YES.

Did I improperly clean and oil it.. NO. Infact I NEVER got the chance to clean and reoil the filter.. The filter was OVER OILED BY THE FACTORY.. I did not realize it was over oiled from the factory (but in hindsight all the oil dripping off the filter when I unwrapped it should have been a warning to me) when I put it in but it was..

Once it fouled the MAF I threw the sorry excuse for a filter out and put a standard paper filter back in..

In the end I spent $50 for the K&N AND also paid $20 for the filter wash and recharge kit..

A new paper filter only cost $10 and replacement intervals for that vehicle was 30K miles.. For the $70 I spent on the K&N I could have bought 7 paper filters which would have got me 210,000 miles not including the original filter that came on the car.. So much for "saving the world" by not using a paper filter..

I realize there are many K&N huggers who fully believe in it's "value" but from my own personal experience it is all bs and marketing doublespeak hype..

Waste your money, I really don't care if you do.. But for me, never, ever, ever again on a K&N or any other non factory filter..

d1h wrote:
Who has replaced their stock air filter with a K&N? Are they really better? Improve performance, gas mileage, etc.

I doubt in many of those responding speak from actual experience with the product.

Improve performance ?

Improve gas mileage ??

I've used a K&N OEM drop in replacement filters over the years with no issues on gas and diesel engines. The last gas powered truck with a K&N drop in OEM type ran for over 230k miles with no issues (same cleanable/reusable filter).
Never noticed any mpg gain but the truck did have a bit more more seat of the pants improvement while towing which helped the engine run a little easier while towing.

I use a older AFE pro 7 filter on the on my '03 Cummins since it was new. No issues in 255k miles.
Never noticed a fuel mileage gain but it did drop the Cummins EGT around 100 degrees while towing. I would see 1300 degrees temps on the Westach before and 1200 degree max after installing the Pro 7.

Will the K&E do anything for your tow vehicle ?? Can't say as its gonna' depend on the tow vehicle.

Turtle n Peeps wrote:

rhagfo wrote:
More air flow equals less filtration.

This is not a true statement.

If you read the Spicer report you will find out that there are several OEM air filters that out perform the K&N filter "air wise" AND filter better. The one on my LBZ Dmax does.

OP you will never see a mileage gain with a K&N filter if you have modern fuel injection on your TV and here is why.

Modern FI computers keep the air/fuel mixture just right. And I do mean "JUST RIGHT". Last time I checked, (A long time ago) the putters would update mixtures rates 100's of times a second. Yes they are that good. The term is stoichiometry.

So you can see if you get more air in your engine (with a K&N filter) you will also get more fuel so there is a zero sum gain in mileage. Now in the old days when carburetors were around most were set slightly rich so you would not have a lean spot in the throttle. That is when you would pick up a little mileage with a K&N because it would pass more air and lean the engine up a bit and you could pick up a little bit of mileage.

Anybody that say's they gained mileage with a K&N on a FI engine is full of it. They "might" be able to say they picked up 1 or 2 HP. Even that is up in the air to be true or not because of different restrictions in the engine.

Good post.

This comes up in this and other forums occasionally, and it is always a long, but needless debate for modern vehicles. If the K&N does allow more air flow, but the computer doesn't utilize it, what good is it? If the K&N doesn't filter better (and it doesn't according to many tests), why bother? IMHO they don't really hurt anything as long as you take the time to properly clean, and oil them when needed, and I guess it's true that you wouldn't have to buy paper filters for a few years, but noticeable gains in mileage, power, and even filtration? Not so much.

tinner12002 wrote:
To each his own but after going to the Cummins forum I decided to take mine out and stay with the stock filter...didn't want to screw up MAS sensor and didn't see any difference in mileage or performance either one. Maybe if I had an all out racing motor then maybe I could have seen a difference. Most people on the Cummins forum say to stay away from them but again to each his own. I have one just barely used if you want to purchase it...cheap.

It's not going to do you any good on your truck. Now if you were boosting 40# then yes. I've had on in my 2005 for 10 years and the MAS is clean as a whistle. Just cleaned the filter last weekend and checked the MAS and inside the plumbing.

To each his own but after going to the Cummins forum I decided to take mine out and stay with the stock filter...didn't want to screw up MAS sensor and didn't see any difference in mileage or performance either one. Maybe if I had an all out racing motor then maybe I could have seen a difference. Most people on the Cummins forum say to stay away from them but again to each his own. I have one just barely used if you want to purchase it...cheap.

Bamaman1 wrote:
They're okay on gas engines. But they're totally ineffective on a diesel engine.

Diesel engines' high compression also make the intake air act differently than a low compression gas engine. It sucks dirt right through a diesel K&N air filter.

On a gas engine they don't make any difference at all performance-wise until the throttle is all the way open. As long as the throttle is, well throttling, the pressure drop across the filter is insignificant.

Diesels don't have a throttle so they ingest a lot more air than a gasoline engine of the same displacement naturally aspirated. Add a turbo and they are moving up to 3 times the air. Compression ratio has nothing to do with air flow on the suction stroke.

I agree with many here in thinking the K&N is a waste of money and has the potential to do more harm than good.

Don't waste your money

They're okay on gas engines. But they're totally ineffective on a diesel engine.

Diesel engines' high compression also make the intake air act differently than a low compression gas engine. It sucks dirt right through a diesel K&N air filter.

I use a AFE intake filter and have a Super Chip programmer on my truck. I have had them on for about two years with no issues. INo fuel savings and no issues with any sensors and love it. They have made my truck so much fun to drive.

As far as mileage, on a gas vehicle you will see no difference between a new OEM filter and a K&N..

On a diesel, the more flow the better the possible mileage and or power.


Gas has a throttle plate and regulates the air fuel ratio.
Diesel has no throttle plate and is wide open all the time as much air as the engine can suck......diesels never run lean, they just stop making power.

I run the "Donaldson" Ford AIS intake box and filter.