FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: mmason on May 01, 2017, 10:19:27 AM
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I have often wondered what kind of flow restriction there were with the air filters that I have put on my engine over the years. I decided to give them a flow test on my flow bench.
I used my 950 quick fuel carb. for testing the filters. I can only pull 28" of depression on two of the barrels at a time so I did one primary and one secondary and plugged the other two barrels.
I also covered half of the air filter so I ended up with half a carb and half a filter for testing. All of the bases, tops and filters are K&N except for the 2 inch paper filter witch was a Aflotech filter that I happen to have.
The carb flows 590 cfm at 28" with two barrels and no air filter. The biggest thing I noticed is sometimes the x-stream top works well and sometimes not.
Filter Size Base Top Flow at 28”
2 in paper Standard Solid 495
2 in paper Standard X-Stream 577
2 in non-oiled Standard Solid 575
2 in non-oiled Standard X-Stream 585
2 in Standard Solid 560
2 in Standard X-Stream 580
3 in Standard Solid 582
3 in 1 in drop Solid 582
3 in 1 in drop X-Stream 584
3 in Standard X-Stream 585
4 in Standard Solid 585
4 in Standard X-Stream 589
4 in 1 in drop X-Stream 585
4 in 1 in drop Solid 585
3½ in non-oiled Standard Solid 589
3½ in non-oiled Standard X-Stream 588
3½ in non-oiled 1 in drop X-Stream 586
3½ in non-oiled 1 in drop Solid 589
Made one change to the 3in drop after retesting
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That KnN lid made a big jump with the 2 inch filter. When I was looking at my old air cleaners for the best use. The best looking one I had was an air cleaner from a 58 332 Ranch Wagon. But with the resenator the stock filter size was only good for a 292 at 5500. Gutting the resenator would have helped but it was not far from the inlet being a restriction. If I remember the inlet was only good for a 4500 rpm 390. It was too nice of an air cleaner to start cutting on so I used a dual snorkle from a 1974 Dodge motorhome and ran duct work to the radiator support. I figured the dual inlets are good for a 5500+/- 430 cubic inch.
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Great information, Michael, thanks for posting that! I frequently used those K&D filter tops when hood clearance was a problem, but never really knew if they were effective or not...