Stock Air Filter, How Much Restriction?

[Gypsyman]

Has anyone done actual flow testing to see what the flow restriction numbers of the stock air box and filter really are? How about hooking up a vacuum gauge to where the air restriction indicator is and actually seing what the stock filter draws versus an aftermarket filter? After working for a number of diesel dealers I don't care what the factory indicator shows, most are junk right out of the box from what I've seen!

 

[Badunit]

Nope, haven't done any of those things. I did, however, cut a 4" diameter circle out of the bottom of the air box (and added a short piece of drain pipe elbow) and my filter minder, which used to pull 35% or more with a new filter, barely moves now. So, from a relative point, the stock box seems to be the more restrictive part of the system.

 

[RDietze]

the stocker flows between around 350 cfm @ 1. 5"h20. compared to the afe mega force 850 cfm, afe progard 7 698 cfm, bhaf around upper 600ish cfm (all at 1. 5" h20)



i have a graph i can email you if you pm me

 

[Gypsyman]

Thanks for the numbers. Are these cfm's for the media only or in the filter housing. I'm looking for the flow # of filters in the housings.

 

[RDietze]

Originally posted by Gypsyman

Thanks for the numbers. Are these cfm's for the media only or in the filter housing. I'm looking for the flow # of filters in the housings.

the stock cfm number is the only one using the stock air box - both afe units don't use the stock box and have their own housings that leave the filter out there more out in the open but shield some/most of the engine compartment heat from being taken up in the intake

 

[Gypsyman]

Are there any replacement filters other than the K & N, and do you know what the numbers are for the K & N in the factory housing. The reason I ask is that I'm about to open up the bottom of the factory box and add a ram air tube but only if I can justify cutting the factory box. The fender feed on the factory box just seems too small to feed this size intake system.



Gypsyman

 

[BHaner]

I have an aFe drop in filter. Seems to work much better than the stock paper and foam filter. It looks just like a K&N except it was cheaper.

 

[RDietze]

amsoil makes one too -- heard a lot of good things about it. i would go either afe or amsoil

 

[XcumminsX]

how does a scotty 3 compare to the afe cfm numbers? anyone know

 

[RDietze]

Originally posted by XcumminsX

how does a scotty 3 compare to the afe cfm numbers? anyone know

wildcat diesel has not performed any flow numbers for the scotty ram air 3, BUT, the filter element is nearly TWICE the size of the afe mega force filter (which flows in the neighborhood of 900 CFM @1. 5" h2o. PLUS, the air to the scotty is forced/rammed into the scotty box. the scotty takes NO air from the engine compartment as an afe mega force takes in a mix of outside/inside engine compartment air.



advantage: scotty ram air 3



not affiliated w/any vendor

 

[draymorris]

how much cfm needed for the stock turbo

I understand that different filters allow diff cfm - but how much is actually needed to keep the turbo supplied with no restrictions. Seems like x psi boost should equel "x" cfm.



Does anyone know?