K&N filter options (small)

Discussion pertaining to positive pressure E28s.
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Nebraska_e28
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K&N filter options (small)

Post by Nebraska_e28 »

What's the smallest round or oval K&N that can be safely used on an m30 turbo application? If surface area is less than that of the stock filter, is it safe to assume cleanings will be needed on a more frequent basis? My question is based on clearance/setup restrictions. TIA!
Shadow
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Re: K&N filter options (small)

Post by Shadow »

i have the smallest specter pepboys filter because that's the biggest i could fit.
removing it on the dyno gave me 20hp @ like 25psi it's been a long time so can't be exact.
yeah it gets dirty fast but i just throw it away and get a new one every 3 years or something.

you can see it's about 1/2'' from the radiator. impossible to use anything bigger
https://www.spectreperformance.com/sear ... ifications
ImageSoon by jet jones, on Flickr
Last edited by Shadow on Apr 30, 2018 4:14 PM, edited 1 time in total.
George
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Re: K&N filter options (small)

Post by George »

This really depends on the power you're trying to make. In general terms, the smaller the surface area, the greater the pressure drop for a given CFM.

Pictures of the current and proposed setup?
marc79euro645
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Re: K&N filter options (small)

Post by marc79euro645 »

I'm using a larger k&n style cone with an early m102 y pipe recirc setup. Once while driving with the hood off I noticed that every time I shifted the recirc boost would cause my airfilter to blow off dust. I've run this setup for about 15 years now and never cleaned my air filter. It looks brand new right now! I know this sounds crazy, but it's true.
Nebraska_e28
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Re: K&N filter options (small)

Post by Nebraska_e28 »

George wrote:This really depends on the power you're trying to make. In general terms, the smaller the surface area, the greater the pressure drop for a given CFM.

Pictures of the current and proposed setup?
Doing a m106 in an m102 car. They have different air boxes/intercoolers & to add, this car had the a/c lines routed slightly different. Will try for pics this week. I wanted to stick with the factory airbox for the look but may have to do a k&n setup.
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