I've received a bunch of PMs about the K&N i'm running on my setup. For those who need a low profile 4 in diameter filter, K&N RU-2510 fits the bill, $32 from Jegs.

Tapered Filter
Flange Dia.- F: 4'', 102 mm
Base Outside Dia.: 5.375'', 137 mm
Top Outside Dia.: 4.375'', 111 mm
Length- L: 3.5'', 89 mm
Top Style: Rubber
Flange Length-FL: 0.625'', 16 mm
Flange Angle-FA: 0º
Flange Offset: 0''

 

http://www.jegs.com/webapp/wcs/store...1_758719_10269

 

thanks rich

 

same one i have i think

 

also the cheapie from advanced works fine!

 

oh, not KN but looks similar!

 

I use a K&N RU-2520 on my greddy setup, fits great. Probably pretty close in size to the one goodfella posted.

Edit: http://knfilters.com/search/product.aspx?Prod=RU-2520

 

here is the advanced autoparts one.

 

Yeah, that sucker is 5 inches long vs the one I'm forced to use, which is 3.5 inches long. My radiator inlet hose is basically touching the filter as it is.

 

the only thing witht these filters the rubber cant take the heat from the turbo and will melt and possibly send rubber through turbo.
be sure not to tighten the clamp to tight but rather loosely.

also because it cant take heat rubber gets really hard and hard to remove and reinstall because it comes too stiff and not flexible anymore

 

Oh, hah, mine touches the radiator hose too, you're turbo must sit a lot closer, maybe even 1.5 inches closer

 

Ha! I've been looking for something like this since I heard the Greddy Airinx I'm using now is a POS. So what's the biggest one I could squeeze into a the tight space between a T78 and the rad hose? Thanks

 

Only you can answer that.....measure the distance from the edge of your turbo inlet to your rad hose.

 

**** i would like to find a filter like this... where can i find one with less than 3.5 inch long? i have a a-spec long runner manifold and i havent find a filter that fits.

 

Max! Havent seen ya posting or on AIM in a while

I'm running the long runner manifold from ASpec. Order it from Jegs in the link in post #2.

 

bump b/c I'm getting more questions about this little sucker.

 

Sweet!! I just bought one.

 

is there any indication that this filter is in some way restrictive because it's so small? I have never seen any conclusive evidence about filter service area vs flow, and in turn its effects on power

 

Does anyone make a 4"x2.5" filter? I seem to be screwed with clearance.

 

Yikes! I wouldn't feel comfortable going much smaller than what I already have to deal with.....

 

Sounds like a personal problem

On a more serious note, I would have to agree with you. We went through this debate on another vehicle a while back. The CFM that the smaller filters flow is not very turbo friendly. They work, but they definitely choke the system a bit. Sure better than not running one at all though...

 

I found it gets dirty very quickly, at least on my car with lots of driving. I'm now able to run a longer filter with my new turbo placement, a 6" K&N so I'll see how long this one takes to get bunged up.

The shorty on my car with my driving (and level of dirt out here apparently ) would get BLACK after 7-8000kms.

 

where did you get that flex hose for your radiator? That may solve all my problems since I have a custom hard line that is causing my clearance problems.

 

Probably also from advanced auto. I have something similar with chrome ends that you can either get at a local parts store, or search on summit racing.

 

yeah I got one from some online speed shop. Worked great, got that filter too.