You know how I really know it works? My average gas mileage went up 2 MPG even in the winter!
So much for that old stock cold air system. I'll take that mileage any day....

I did something different on my 535i. As I stated on the Gallery page last year I was going to tell everyone about it but I needed to find a P/N...Anyway, I removed the air box assembly and directly attached a large KN filter to the 90 deg. plastic bend that comes off of the flapper box. The KN was from a Buick Grand National aftermarket Kenny Bell ram air set up. It was an almost clean installation. I need to fabricate a small bracket to stabilize the set up and keep the filter from getting damaged by moving into surrounding components. Now the performance is noticable if you are sensitive to that sort of thing and know your car but what is extremely cool is the sound. The car growls (the only way to describe it) especially at high RPM. Roll the windows down and enjoy. It also looks cool under the hood and one could install some exhaust heat shielding and some mild duct work to the general area. Don't think that installing a closed air tube around a filter and bringing the airin from somewhere else will help. The filter must not be shrouded. If you get to see other ram air set-ups on Jap mobiles you'll see a dirt pattern on the KN only where the air is hitting it directly.

Mike H.
86 535i lowered, w/M3 wheels, exhaust, KN, and Bilsteins Sports by this weekend....202000 miles
In the roadfly gallery if you look deep enough.
just wondering if anyone has tried making their own CAI like the imports have all over...just wondering :) found a websight that said how to make one for a del sol http://www-personal.engin.umich.edu/~etang/Making%20Your%20Own%20AEM-Style%20Cold%20Air%20Intake.htm and wonder if it could be done w/ a 533i :)

mark