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Thread: K&N air filter kit

  1. #1

    Exclamation K&N air filter kit

    from Routineer;

    Ordered a pair of K&N filters for the Z8 for about $100. Had good results with K&N on an M3 and expected the same. Kinda like the "voooomp" sucking sound when I'd get on it, and it does promote easier breathing.

    The Z8 airboxes are a little tedious to open, and don't clear the headlight housings without a struggle. Could scratch them going back on if I wern't careful. Might of been better if I disconnected the big hoses that feed the manifold airbox on the engine block. Put the filter elements in and discovered that they fit real sloppy. Then checked the box and discovered the instructions (uh, duh!) for the grey foam adhesive/paper-backed gaskets that have to be installed in the filter box prior to installing the filter elements. We're talking cheap 1/8" die-cut foam about 3/8' wide to fit around the perimeter of the inside of the air box where the more rugged foam filter elements normally seat. They didn't stick that good due to the loose hydrocarbons (mold release?) on the plastic airbox, and I'm sure that they wouldn't last the alleged million miles life of the filter elements themselves. These gaskets will probably wear out or tear after just a few filter removal/cleaning/re-installs.

    Bottom line - I put them both back in the box, reinstalling the OEM filters, and sent them back for credit. Hey, K&N man - lose the tux and buy more tooling! If it doesn't fit, don't sell it.

    Meanwhile, assuming you're not counting the chrome rear license plate frame, the Nurburgring sticker and the wired-in Escort 8500 mount, the Z Acht is still box-stock, not that there's anything wrong with that!

    Andrew Macpherson

    Expert Z8 Inspections, with full support for both Z8 sale and purchases.

  2. #2

    Exclamation MAF issues with oil based filters

    I have been reading much about the issues that K&N and BMC oil based filters have been causing the S62 owners in M5's. The main issue is that the oil from the K&N's in particular contaminates the MAF's.

    These units control the ignition timing and the air-fuel mix, and if they get the oil that this type of filter uses on them they need replacing. They will start out by limiting the power above 4,000 miles, and will eventually make the car almost impossible to start.

    The EPA mandates that MAF's must be gauranteed for 100,000 miles on any car sold in the USA, so BMW NA will put new ones in if they fail before that. However be warned that BMW won't want to replace them if you turn up with an aftermarket air filter in your car.

    After reading much about this I can say that there is no real benefit to using one of these filters, you are just opening an unnecessary Pandora's Box, so stick with the OEM paper and save yourself a major headache.

    for more info on MAF's and their problems with oil based filters do a search on the M5board
    Andrew Macpherson

    Expert Z8 Inspections, with full support for both Z8 sale and purchases.