Hi

Looking for a small 4" air cleaner for 600-650whp. I do run a pretty big KN now, but want to reroute the air filter and need a smaller one. It must have 4" inlet.
Any recommandations?

Thanks

 

Rule of thumb:
Determine desired flywheel hp, multiple by 1.5, and you get cfm required.

700hp(flywheel) x 1.5 = 1050cfm

You will probably need at least a 9" K&N.

 

Thanks, but I meant 4" inlet flange. It seems like KN doesnt give any hp/flow info on the filters...
I could not find any 4" Amsoil filters on Amazon.
What filters are the 600 whp guys running when minimum space are available?

 

could try the perrin, you would need a 4.5 to 4 adapter tho, its fairly compact and i would say it flows pretty well seeing as its just foam over the end of a pipe

 

buschur sells one, its what i use

 

I have a 4" k&n on my car and I made over 600

 

Roger, my reference to 9" is the total length of the filter that is assumed to be flanged for a 4" inlet. While K&N doesn't post flow specs you can call and they make a quick calculation. Their flow numbers relfect 1.5" H2O pressure drop and here is what I found...

K&N RE-0870 (901.67cfm) - 9" long cone filter
http://www.knfilters.com/search/prod...x?Prod=RE-0870

K&N RE-0860 (1202.23cfm) - 12" long cone filter
http://www.knfilters.com/search/prod...x?Prod=RE-0860

With that said people will post they have achieved 600hp@wheels with smaller filters. This may be true, but it is a restriction as compared to a properly sized filter. Same argument you see when English Racing reports 30-40hp@wheels gains when removing the MAF and switching to speed density with no filter.

I think you get the idea, running a smaller filter will hold back power.

 

EA 4560, we have a buch of them

 

https://secure.buschurracing.com/cat...oducts_id=1548

 

The Amsoil EA 4560 is a replacement for the K&N version RU 4740:

RU4740 - 582cfm @ 1.5" H2O

I am not sure how much more flow you get from the Amsoil version listed above.

 

Thanks all

Jrod
How much hp is it rated to? Looks very interesting.

 

There was a test conducted and ASMOIL came in 2nd out of over 5 filters, in filtration and flow.

many folks running it, with small and big turbos

https://www.evolutionm.net/forums/ev...t-results.html

 

We had that filter custom made for us from a BIG name filter manufacturer.

Its the same filter that we run on the BAD BISH... so we know its good over 700whp on our Mustang Dyno.

 

Thanks Jrod

That is more than enough for me I will place an order in your webshop.
Thanks

 

You're welcome! Thank you for your order.

Glad I could help!