The oil problem is more apparent with the gauze/pleated type of filter than with the foam type. It is very easy to over-oil these filters and thus contaminate the intake path. If you are careful about oiling, you probably won't have a problem. But it is easier to get a foam filter oiled properly than it is the pleated type.

 

comes from the filter or the crank case vent system. in the Supercharged cars, you get a bunch of oil in the intake path anyway......

Matt

 

If there were a problem with the filter letting in dirt, you would have had higher concentrations of both aluminum and silicon, and in a very specific ratio. Both samples you posted are very low in both Al and Si, so whatever the differences are between the two samples, the amount of ingested dirt wasn't one of them.

 

Any figures on the the amount of negative pressure (suction ?) created behind a filter in say the R56 compared to a NA engine of at least 3 litres in size ?

I ask as I was wondering if it was a lot higher in a small displacement turbo car and that the oil was being "sucked" off
Same oil issue was around on my 2002 GTI when I had one.

Just a thought

 

I would think that if the filter was properly sized and oiled for the application the oil wouldn't be a problem. If the filter is undersized for the car then that might be a legitimate concern.

 

I ran a K&N cone style filter in my 1998 F150 for about 100,000 miles after replacing the stock filter at around 25k or 30k miles. I cleaned and re-oiled it about 3 times in that period. Never had a MAF sensor problem. I sold the truck to a buddy at 127,000, and he has around 167,000 miles on it, and I believe he still has the K&N (I'll have to check with him). Still no MAF problems, anyway, as I talk to him every few weeks. The truck uses no perceptible amount of oil at 5k mile change intervals.

That being said, I don't know that it proves anything...