Pistol Pete

I just bought an '87 944 non-turbo and I'm picking it up on friday. I'm very exciting and I was considering a K&N filter as a congratulatory gift to myself. Do these things actually free up any additional power? From what I understand, the 944 is engineered pretty close to optimal performance for this engine and bolt-ons dont do much. Anyone have good luck with aftermarket filters adding a little power? Better sound is always good too. If not K&N, what else?

testarossa_td

Big debate here.

I have always used K&N but have found dirt in my BOV so something is getting by.....but then again I use MAF now and have the same situation with the K&N cone.

When I ran stock I did not find dirt.

ubercooper

here we go again....
but I too am curious about the filters. I have heard ALOT against and for them and always confused by the end.

Mark-87-951

Does anyone make cone filters with paper or similar to oem filtering ability? I like the clearing up of the engine compartment using a cone filter creates but I'm worried about the wear on the engine that might be increased should I ever go that route with a k&n type filter material.

Techno Duck

I used a K&N panel filter for probably the last 20k miles. On a whim i bought a new Mahle paper filter and put it in about a month ago. I noticed no difference at all....not even with sound.

DanG

I've seen back to back test data (confidential, sorry I can't provide it) on both restriction and filtration for K&Ns verses OEM filters on a few different vehicles. K&N acheives lower restriction due to poorer filtration, period. The sacrifices it makes in filtration are much greater than the gains it makes in restriction.

People will line up to tell you that they've used K&N for years or (tens of, hundreds of) thousands of miles and report no issue. That may be true, but they did allow significantly greater amounts dirt into their engines, and their engines do have higher wear than if they used the stock filters. For the record, I have used K&N filters in my personal cars for thousands of miles as well. I intend to swap in better alternatives on the next replacement.

K&N filters are particularly bad when it comes to 'Fine' dust, as opposed to 'Coarse'. Fine dust causes the majority of engine wear.

You don't even want to see the data on a "recharged" K&N. They're certainly low restriction, I'll say that much!

89AZ944

Pete-

If you are in a dusty climate (AZ, NM, TX, etc.) the K&N gets dirty VERY quickly and requires cleaning and reoiling on a much shorter service interval.

I have found that I have to replace my regular filter about every 8,000 to 10,000 miles (three times in 3 years for me) and would not look foward to messing with a cone filter.

Just a thought....

89AZ944

Mark-87-951

What do you guys think of this filter?

AEM Dryflow synthetic filter

Laust Pedersen

Certainly not the first time this has been discussed, so here are some past references on the subject:
http://forums1.roadfly.org/porsche/f...4959457-1.html
http://www.bobistheoilguy.com/airfilter/airtest1.htm

I too did some informal testing on a V12 with a K&N in one side and an OEM Baldwin paper filter in the other. After 500 miles I sampled whatever was in the intake tracts and subjectively judged the K&N side had twice as much with twice as large particles.

Btw, the paper filters I have seen also appear to have much more surface area than the equivalent K&N filter.

I stay away from K&N filters in my cars (especially those with “soft” cylinder walls).

Laust

Pistol Pete

I'm in Minnesota, so not too dusty but it doesn't sound like there are too many positive reports on the K&N. Can anyone recommend a good aftermarket air filter, or just stick with stock? Like I said, I was just looking for a congratulatory car gift to celebrate this new 944, but I certainly dont want extra engine wear or loss of performance.

The DareDevil

Since there wasn't a large price difference, I bought and installed a replacement K&N air filter. I haven't noticed any difference in terms of power. Maybe a couple extra miles out of a tank of gas at best.

fezz

value, none IMO
i ran one for 2.5 years, just switched back to paper and no noticable difference.
stick with stock.

mavfan

the dust concept is troublesome to me. when buying K&N i thought i was getting the best of both worlds. guess not

Dave951

K&N makes filter wraps for there cone filters. I heard guys saying that after using a filter wrap there was a significant reduction of dirt inside the intake track. I dont have any hard data to backup these claims but it seem plausable. Combining the benefits of a wet gauss filter with a foam precleaner OR the precharger bag. You can check out the filter wraps here
K&N Precharger Information & Sizing

85944na

I had one, PO put it in, I took it out and threw it away, the 7$ factory paper filter is worry free, and not hard or costly to replace.