In my project thread, the Engine Master's Air Filter test came up. It's pretty interesting, so I thought I'd make a separate thread to discuss it further. The video is here: The engine used in the test is a 489 cid big block Chevy making 752 hp @ 6600 625 @5900. The way I see it is that these air filters would only cause a loss in power once it can no longer supply the CFM of air the engine requires. So I think some of these losses are exaggerated because of the engine being used which would use a lot of air. The test engine would require 933 CFM at 6600 RPM (at perfect 100% VE). Obviously a smaller street engine which will have a lower CFM will not have near the same airflow requirements. They "estimated" the power the filters were good for based where on the hp curve it started to lose power over a open carb baseline. It would have been nice to know what RPM that was, so we could roughly calculate the CFM limitations. In the end though, it seems that your typical open element air cleaner is actually pretty good. In fact the cheapo 14x3 Mr. Gasket special with a Fram filter was in the top ten, only costing this monster engine 10 hp at peak (1.3% loss). Also surprising was the flipped lid OEM only lost about 12 hp (1.6% loss), pretty much on par with the open element filters. In there test the dropped centre filters all ate up more power, except for the B&B Drop center. It only lost 8.9 hp (1.2 % loss). This one seems to be the bargain, as Summit and Jegs has it listed at about $45 and would offer good hood clearance. Further, it seems small filters are consistently bad, and foam filters are also very restrictive. So I think for most of us running on the street, a open element filter is not a bad choice. However, I guess this doesn't take into consideration the engine heat that it will be exposed to. A fresh air intake would have the advantage their, but even a dual snorkel air cleaner seemed to be pretty restrictive. I made a chart of the results. The HP Loss/Gain shows how much less power this engine made compared to it's 752 hp baseline. Ie , the first filter was -145.1 hp means with that air filter the engine only made 606.9 hp, or it made 145 less than the 752 hp baseline peak. The Max power is the testers estimate of the maximum horsepower this type of filter can support. So the first filer is by their estimation only good for an engine that makes less than 300 hp. The third column is just the hp loss translated into a percentage. So for example the first air filter resulted in a peak power loss of 19.3%! It also shows how close some the top ten results are, probably not enough to feel. The results are here:
Air
Filter | HP Loss/Gain | Max Power | HP Loss/Gain | 6.5" x
2.5" (paper filter) | -145.1 | <300 | 19.3% | Single Snorkle
OEM (paper filter) | -95 | 300 | 12.7% | Velocity Stack
with foam filter | -72.4 | 300 | 9.7% | Fly's Eye
(foam filter) | -71.1 | 350 | 9.5% | Dual Snorkle
OEM (paper filter) | -53.1 | 390 | 7.1% | 10" x
1.25" round (paper filter) | -18.8 | 650 | 2.5% | 14"x3"
dropped base, with K&N Filter and filter lid | -18.8 | 650 | 2.5% | 14"x3"
dropped base, with K&N filter | -12.7 | 660 | 1.7% | Dual Snorkle
with flipped lid (paper filter) | -11.9 | 640 | 1.6% | Flat Base
14" x 3" (paper filter) | -10.1 | 640 | 1.3% | B&B
14"x3" dropped base, K&N filter | -8.9 | 660 | 1.2% | 14"x3"
flat with filter lid, K&N filter | -7.2 | 675 | 1.0% | 14"x3"
flat base solid lid, K&N filter | -6.6 | 675 | 0.9% | 14"x3"
flat base taped sides with filter lid (K&N filter) | -3.5 | 675 | 0.5% | 14"x4"
flat base | -1.2 | 750+ | 0.2% | Open Carb | 0 | | | K&N
Velocity Stack | 0.9 | 750+ | 0.1% | Salad bowl
with filter lid | 3 | 750+ | 0.4% | Velocity
Stack (no filter) | 5.7 | 750+ | 0.8% |
Any thoughts on this and the results? At the very least, this can be a future reference.
------------- Vince
1972 Ford GTS Sportsroof - Survivor, One Family car
GTS.org Admin
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