Air filter shootout

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dukeboy440

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Hadnt seen/found this posted so I think its worth bringing up.

Engine Masters on Motor trend did a few weeks backs an air filter setup comparison.

The base engine is a 496 CI Chevy(gulp) making 750 hp without any filter. Listed below are their combos and the resulting hp those filters will support. + means gained hp, - means losted hp from peak hp of the base engine.

19: 6.25 x 2.5 mini filter= -145.1 for a max of <300
18: Single Snorkle mopar big block = -95.8 for a max of 300
17: Foam filter Velocity stack = - 72.4 for a max of 350
16: Fly's eye(the triangular eddlebrock set up that is somewhat popular) = -71.1 max of 350
15: Dual Snorkle Mopar= -53.1 hp max of 390
14: 10x1.25 short air filter, paper element = -33.5 max of 350
13: 1.5 inch drop base, K&N 14x3 inch filter with K&N filter lid= -18.8 hp max of 650
12: 14x3 k&N filter, 1.5 drop base, flat solid lid= -12.7 for a max of 660 hp
11: Dual Snorkle Mopar with the lid flipped upside down= -11.9 hp max of 640
10: 14x3 flat base and lid with fram filter= -10.1 for a max of 640
9: B&B lid with K&N filter= -8.9 for a max of 660
8: 14x3 with K&N filter lid, flat base= - 7.2 for a max of 660
7: 14x3 flat base with solid lid, K&N element= -6.6 hp and max of 675
6: K&N filter lid with 14x3 flat base, element tapped up= -3.5 for 675 max
5: 4 inch tall, 10 in, flat base, solid lid= -1.2 hp and 750+
4: Open carb, base line: 0.0
3: K&N velocity stack with filter lid= 0.9 for a max of 750+
2: Homemade "Salad bowl" with K&N filter lid= +3.0 hp and max of 750+
1: Open, no element, Velocity Stack= +5.7 hp and max of 750+



Just some food for thought.
 
Here's link to the video Enginemasters Air Filter & Housing tests

It is interesting.

One key factor: RPM
Of course now I've forgotton the baseline peak rpm in that test, but I think it was somewhere around 6500 - 7000 rpm.
If the engine maxes out at less rpm, and has less displacement, then less surface area and more restrictive filter material/screening can be used with no measurable effect on peak Hp.
That's the basis the guys used at the end to make some rough top of the head estimates of how much Hp each combo they tested could be OK for.*

One effect of the air cleaner shapes that the graphs would show (if we could see them all) is the impact on the bowl vents. Air flow into the venturi is important, but changing the pressure in the bowls can do both good and bad things. With Holleys on a NA engine, its best to have consistant pressure in bowls. I speculate that the downflow only shapes may have upped the bowl pressure; where as the downflow with sideflow created turbulence and inconsistant pressures in the bowl.

*For example.
15: Dual Snorkle Mopar= -53.1 hp max of 390
means this combo made around 700 Hp, 53.1 Hp less than the baseline of 750.
and it would be fine for any engine up to 390 Hp.
 
Last edited:
Here's link to the video Enginemasters Air Filter & Housing tests

It is interesting.

One key factor: RPM
Of course now I've forgotton the baseline peak rpm in that test, but I think it was somewhere around 6500 - 7000 rpm.
If the engine maxes out at less rpm, and has less displacement, then less surface area and more restrictive filter material/screening can be used with no measurable effect on peak Hp.
That's the basis the guys used at the end to make some rough top of the head estimates of how much Hp each combo they tested could be OK for.*

One effect of the air cleaner shapes that the graphs would show (if we could see them all) is the impact on the bowl vents. Air flow into the venturi is important, but changing the pressure in the bowls can do both good and bad things. With Holleys on a NA engine, its best to have consistant pressure in bowls. I speculate that the downflow only shapes may have upped the bowl pressure; where as the downflow with sideflow created turbulence and inconsistant pressures in the bowl.

*For example.
15: Dual Snorkle Mopar= -53.1 hp max of 390
means this combo made around 700 Hp, 53.1 Hp less than the baseline of 750.
and it would be fine for any engine up to 390 Hp.
yep.
 
What makes me smile is that an old trick from back in the day was tested such as the "flip the lid upside down". I also remember some 426 Max Wedge guys running velocity stacks and pulling off the elements just before slamming the hood shut prior to their run.
 
I had noticed that the stock air cleaner was providing a restriction at the track, although I never actually tested back to back. Not hard to figure when you think that the stock lid only provides about 1/2 to 3/4 inch clearance around the bottom. I took and old air cleaner and modified a lid so the filter would be fully open. I run a K&N filter and I just swap lids when I get to the track.

IMG_4484.JPG


IMG_3986.JPG
 
Guess im good then with my dual cut out filter housing.

I wonder how it would compare to different hood setups though? For instance on my demon the hood scoops direct fresh air right near the opening in the housing, wouldnt that allow more airflow than a hood without fresh air ports even if you were running a standard open side filter?
 
Guess im good then with my dual cut out filter housing.

I wonder how it would compare to different hood setups though? For instance on my demon the hood scoops direct fresh air right near the opening in the housing, wouldnt that allow more airflow than a hood without fresh air ports even if you were running a standard open side filter?
Ram air doesn't make a huge difference. A couple hp at the most. And simulating that on a dyno is a challenge unless that dyno happens to be in a wind tunnel. The biggest effect is gonna be from the cooler, slightly denser air charge I would think.
 
I was a lid flipper back in the day. I even did it on dads 75 C1500, although the moaning Quadrajet didnt have much smog strangled cam to work with.
 
Only way an air cleaner would fit.
15092032-E17A-4A77-A2F2-B0FE41E415F7.jpeg

I cut up an air cleaner. All i could find at the time.
 
From the results of the test, it looks like the diameter of the air cleaner is more important than the height.
 
I love the engine masters series (Especially love all the BluePrint Engines they run) haha.

Nice guys in person, down to earth, and alot of good knowledge. I enjoyed the header smashing eposode. Especially since I replaced a set of mildly dinged headers back in the day b/c of all the hp they must have been robbing from my mighty 318. Lol ahh to be 16 again!
 
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