To K&N or not to K&N

[gcp]

Today I finally removed the air box cover and checked the air filter. Found that it was rather dirty so before I replace it could you please advise me as to whether I should stay with the Porsche filter or go to a K&N?

I like and have used K&Ns extensively on my motorcycles and both my Audi and my Volvo but I want to make sure it's ok to also use one on my 996.

Thanks,

[geza]

There are many opinions on the K&N style filter (oiled cotton) vs. the OEM paper element. Various papers have been written that the oiled cotton style allows a greater proportion of super fine grit to pass through the filter, as opposed to the OEM paper elements which seem to do a better job dealing with this fine grit. As for total airflow - one would have to assume that the factory did the job right with filter sizing and paper specification - which would ensure air flow that is more than adequate. Oiled cotton filters do seem to allow a little more induction noise on acceleration - and people in general seem to like that.

Oiled cotton is also able to impact the MAF sensor operation - and can cause CEL events if the cotton is over-oiled.

[AG996LV]

I have a K&N filter and have never had any issues with the MAF. Whether or not it allows more dust through I really can't say. Performance increase... not noticable. The only benefit is never having to replace the filter again, you can just clean it and reuse it. I think biggest difference is that when it gets dirty, the airflow is not reduced as much as a dirty OEM filter.

[BT986]

I agree...I've had my K&N for about a year now, and I haven't really noticed any performance differences. It did idle funny for about 3 minutes right after I installed it, but that is normal. I haven't had any problems. The nice thing about this filter is you can just take it out and clean it instead of buying new replacements.

[quicksilver77]

I just changed to an oil/cotton filter (BMC), about 600 miles ago. About three days after installing the new air filter I went for a spirited drive through the canyons near my home, I did code a check engine light. Being quite sire that it was the new air filter, but wanting to be sure, I took the car to the dealer, who, after verifying that the code was indeed the MAF sensor, wanted to charge me $800 to replace the MAF, as well as install a new paper filter. I of course respectfully declined the opportunity for anal invasion, and just had them clear the code.

Since clearing the code, it has not returned; and I have been to three track events since, so something tells me that it is not going to come back on.

Initially, the oils in the K&N can be pulled into the throttle body, under hard acceleration, and accumulate on the MAF, leading to the check engine code. The code will automatically reset after a few days, or you can disconnect the battery to reset the system.

Performance wise, I think that a clean paper filter will offer similar performance, just a shorter life span. If you are good with maintainance, go paper, if not the K&N will be great.

Either way, enjoy your car!!!

-Sean

Today I finally removed the air box cover and checked the air filter. Found that it was rather dirty so before I replace it could you please advise me as to whether I should stay with the Porsche filter or go to a K&N?

I like and have used K&Ns extensively on my motorcycles and both my Audi and my Volvo but I want to make sure it's ok to also use one on my 996.

Thanks,

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