Leon993

This is just my opinion, but I honestly cant find the benefit of aftermarket air filters. The increase in performance simply doesn't justify the RISK of clogging your engine interior with dust. Dust will kill it slowly.

Maybe its because I live in the desert and there's plenty of dust that Im so concerned about aftermarket air filters. But truthfully there is no technology that successfully filters out pollutants yet maintains a healthy intake of air to an engine than a simple paper filter.

TheOtherEric

I've tried several configurations and now I'm back to a stock drilled airbox with paper filter. Yes you can get a few hp (at high rpms only) with K&N style filter but it's not worth the $ or hassle.

Mike J

Hmmm, not sure I have seen those measurements - have you dyno graphs of each of the filters on the same car?



Like the stock setup, lots of filter area. The only part I do not like is the suction of the clutch area particles onto the filters, and that is easily solved.

Cheers,

Mike

race911

When did we start doing this with 911 engines? 1984, on the first Motronic equipped cars? When did we stop doing this with 911 engines? 1984? Even back in the Fred Flintstone days of data acquisition, we couldn't get any more trap speed up the long straights at Firebird, Riverside, or Willow.

Flying Finn

Yes but who says more surface area is needed?

The restriction here is not the filter element, but what's between the combustion chamber and the filter (think intake itself, throttle body, valves, cams) where the restriction is.

If you have better cams, bigger valves & intake, then you could/would benefit from larger surface area to suck in more air.

Not saying you can't get something from a bigger filter but it's very minimal, if anything what you gain.

That said, I have a cone filter for 993 laying around if anyone is interested in buying.
(I know, I have no future as a salesman)

TheOtherEric

Well actually, I wasn't making that up. I indeed conducted some runs on an empty highway, back & forth, running a couple configurations. There seemed to be a few hp gained but since it could have been statistical noise, I never bothered to post it. But it was pretty clear there was no gain in most of the rpm range and little enough at high rpms that I switched back to paper.

plymouthcolt

Seach for cold air intake or aftermarket intake and you will find plenty of posts about engines throwing codes (like the infamous P1140).

mike cap

Yes, I have some familiarity with the P models. And I'm certain that Porsche used that air filter arrangement on that model because it was optimum. Not so on the 993 and, as I said, they look like ****.

TheBen

I had a cone when I bought my car. The PO installed. I thought it was a bit noisy with no obvious performance benefits so I replaced with the factory Motorsound version. Much happier now!

User 122821

Some testing...

http://www.bobistheoilguy.com/airfilter/airtest1.htm

Paper filtration was far above the cotton gauze or foam filters. Pressure differential was very small. I'll stick with factory air filters since I want longevity over minimal power gain.

Beretta

Drilled my airbox yesterday (993 -95), and tried it today.

Love the "roar" 4000+ rpm.

Now I´m only waiting for my Wong chip, hope it´s worth the money.

TheOtherEric

BTW, I noticed Steve Weiner just posted this week or last that he did some dyno testing on the effect of open airboxes. He found a few horsepower, nothing more. Basically the same thing I noted above from my testing.

Steve Weiner-Rennsport Systems

To maintain context, I'd simply add that cone filters on 993's made less BHP on the engine dyno than the factory airbox with the stock filter in place. This is due to disrupted laminar airflow with cone filters directly attached to an MAFS.

The factory airbox actually flows quite well so for the race cars, we cut away the aircleaner cover, leaving the frame intact to clamp the paper element securely in place. Dyno testing shows this configuration works very well.

I don't recommend this for street cars since the element needs some protection when you wash the car, therefore we usually add 5-6 2" holes to the cover. Its worth a little power over the OEM configuration that's certainly measurable, but not really noticeable.

BMC filters are better quality than K&N's, however neither functions as well as a nice Mahle paper one so that's all we use for race cars as well as street cars.

Beretta

Steve; Great info. Thanks for sharing it.