alibaba

I am still a novice on engines though...

ÅllroÅd :DFW

There was some kind of greasy buildup that didn't seem to burn away. I used cleaning alcohol and a cotton bud and there was a buildup. Consequently, I dunked the MAF in the alcohol per the recommendation of some VW folks.
My guess is that fine particles of oil from the filter settles on the heating filament and messes with the readings.

TyWebb

i quoted the article too. 3 -3.5 inch for a 2.7t stock or chipped is what they recommend.

esfor

The only time you can get less power from a less restrictive exhaust is if you screw up the velocity of the exhaust and the scavenging effect in the headers and collector. But this is almost never. In almost all cases, a larger less restrictive exhaust increases power.

In turbo cars, there is no such thing as a pipe that is too large. You are not going to effect the headers or downpipes in front of the turbos. You should always go with the least restrictive exhuast as possible. I don't know about the allroad, but in the S4 the stock exhaust seems pretty restrictive (although it is quiet and that was their goal in design).

-alex

MartinVW

I have a K & N in my other car, works great! Sounds like it's to be avoided in the Audi, though.