MP4.2+6.0

I would never ever put one in my W12 or in an S8. The MAF is literally screwed to the top of the air filter case perhaps two inches from the air filter. A recipe for nothing but wiped out MAF's.

I know how they are oiled. But repeating the story I have now told many a time. I used one on the C5 4.2. I have oiled them over the years with both the liquid oil and the spray method and let them typically have the oil settle in overnight. I put it on very thinly.

On the C5 it was insidious--it takes the MAF out without you even knowing. I tested it maybe a year or two after it went in and found it was flowing about 210 g/s maximum, or so the MAF thought. Rule of thumb is it flows about 80% of rated horsepower at its peak, so on that 300HP A6 4.2 version I should have seen at least 240 g/s. So, I was down perhaps 15% on HP. Sure maybe mileage was better, but that's effectively because it was running like 15% lean and apparently didn't even know it--no codes until the tranny started flaking into SAFE mode, partly due to the now faulty MAF apparently though the MAF threw no direct codes. A gas motor is tuned at just over 14 to 1, but can run 12 to 1 for power or 16 to 1 for max economy. Meanwhile, when I later pulled the throttle body rubber elbow, I found the telltale red K&N oil finely misted close to 24" away from the filter location, and also uphill in the car air flow design. Very finely misted like you might see over many miles, but also enough to take out the MAF without even knowing it. In retrospect, I think its a pipe dream to think no oil will ever leave the filter no matter how well applied, and in turn virtually any contamination screws up an MAF. The replacement MAF flowed at approx 255 g/s right out of the box and in back to back tested runs with the screwed up one. K&N went directly into the garbage can, together with the old MAF.

Net, having used them on a 1973 C1 carbureted Audi 100LS with a Weber 3232DGAV conversion, I think that's the era they really belong in. Used it on my 85 5000 with an early panel filter box, but didn't notice any benefit; it did not have an MAF in that era of Audi motors and FI. I will never put one on a modern Audi and now firmly view them as a long term performance subtract on a any MAF equipped vehicle.

Car looks great BTW, so this is just a general K&N critique on any modern Audi.

pmdeaver

Beautiful car. Nicely done. Gorgeous!