Air filter difference
 

Is there really a difference from a $15.00 Mahle filter and a $50 K&N for a 1988 carerra 3.2?

um $35? Go with the Mahle..

yes, the filter media is a lot different.

I can't speak to the specific Carrera application, but the K&N have always been hyped to flow a bit better. Although I've also seen some stuff showing a good quality air filter flows almost as good, as long as replacement is appropriately frequent. I've used K&N, and I don't particularly care for the cleaning/re-oiling, but I seem to do it anyway. Also, K&N do have a potential weakness in very dusty situations. Supposedly the guaze is good at catching particles because they'll stick to the oil. But the passages can be larger that with a paper element, and lots of dust can be a potential problem, allowing some to get past the filter.

Buy a new Mahle every year and never look back. K&N requires yearly upkeep to be effecient.

after seeing some data that showed that the air flow through the air filter is not the weak link in flow I now stick with stock. Overall stock filters better per most testing. So my thinking is flow is not an issue and better filtering is good.

I have also seen some poorly maintained or cleaned and oiled K&N's. Too much filter oil and a MAF is not a good combination. A dry or compressed air blasted K&N filter is not good ether. K&N's are a thin layer of fiber between 2 layers of corrugated shape screen. Compressed air can knock the fibers around and leave holes for dirty air to go through. This tends to show up in the peaks of the screen ribbing. I distorted one by over tightening the cap nut and noted that the fibers ended up moving out of place after a while. after cleaning and drying but before oiling i hold them up to a bright light and look through them for starlight holes.

I have a K&N on the Go-Ped and one in the M3, but from what I have read since I put it in the M3 years ago, I do not think I would go that route again. The K&Ns do not do well in head to head tests with paper filters. I have not had any issue over 10 years and nearly 200 track days in the M3 so I have nothing to complain about except you do need to have the car out of service for 24 hours to clean/oil the filter. To do it right, you use low pressure water flowing in the opposite direction of the intended airflow to wash out the cleaning solution. Once it is clean, allow it to air dry - no heat or compressed air. Then oil lightly and wait several hours. Reapply to the white areas of the gauze. It does look cool on the Go-Ped. :roll:

Thanks, I'm going with the Mahle...

My practical experience with testing paper vs K&N filters made me a believer, and is widely used in motorcycle tuning. In my Z1R I could run a larger jet with the K&N filters because of the increased air flow vs a stock paper filter. Went back to the paper filter once when a K&N filter was lost/stolen and fouled the plugs in about 10 miles of riding. If you don't mind 10 minutes of extra work, you can save the increased cost of the K&N filter in a couple years of reuse. I like being able to clean the filter when it is needed without having to remember to order a new filter.

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

its a trade off. You want uber clean, you loose some air flow. You want air flow, you loose some dirt trapping ability.