air cleaners best worst?

jet1 · Post by **jet1** » Thu Jun 07, 2012 6:20 pm

I did some searching and found a bunch of info on here but still did not really get the total picture.
I know that teh K&N filter lids are not good and that teh L88 and Moroso drop bases seem to be the thing to have. There is also some spun fully radiused untis availabe also. I have also seen some info explaining that to tall of an element can work against you.
The new Moroso filter bases are not radiused, they have bent edges vs the L88 is radiused but has bumps and a few things protruding to clear float bowls and such. Then you get to the tops. The Moroso one has a radiused top as alot of the other ones do not. I am sure that ther has been alot of testing done.

So far from what I can come up with I should be using a L88 base with a Moroso top and a 3 or 4" filter x14". Is there an advantage to going to the spun ones such as with http://www.racingjunk.com/Drag-Racing/2 ... quot-.html

MadBill · Post by **MadBill** » Thu Jun 07, 2012 9:02 pm

I've tested a number of 14" spun drop bases and they've all been terrible! The problem is that to clear the floats with room to spare, the spun section is so wide all around it's like a vertical wall 1/2" inboard of the filter and there's no room for the air to make the turn. Sized for a 16" filter they would likely be fine.

Many of the matching spun tops are also bad. (although they look great with that funnel-shaped depression in the middle) In this case, I believe it's the oversize flat center of the depression that blocks the flow.

Re filter height, keep in mind that in the factory installation the L-88 base has a deep sponge ring at the bottom, so a 3" filter is a little tight for flow off the bottom portion. A 3.5" or more height is a better choice for say 400 HP up.

gr9082 · Post by **gr9082** » Thu Jun 07, 2012 9:48 pm

Braswell has a Air filter set up that works

jet1 · Post by **jet1** » Fri Jun 08, 2012 9:45 am

Any dyno info on the brasswell? So If I go with the L88 base and just a normal edelbrock top (I have already) and a 3.5 or 4" element I should be pretty good?
Here the deal My budu and I have a freindly competition going on with a couple of jet boat motors. mine is a 4.070x4.125 ls3 with TEA ported factory heads a 234/238 .602/.603 112l/c cam. Factory ls3 carbed intake 10.4:1 Holley 750 DP.
His is a 4.120x4 SBC 10.5:1 xr294 Hyd roller. AFR 210 eliminator heads,AFR singke plane plastic intake, Holley 750 dp. Both engines should be around 600 Hp@ around 5500-6000( the rpm that we have chosen.

So I am looking for some ways to make a little more power without major engine tear down mods and of course be pump gas freindly. So far I have come up with the following.
1. 1.8 rockers
2. different intake manifold or work on the old one. The runnersa are 3.5" short ones and 6" long ones and an csa of 1.76 at the port. Not real great. I can actually cut the manifold in half and extend the runners up into the plenum some. Or if ther is a better manifold I could just get that one.
3. I can go with a 950 hp carb.

dirtracr5 · Post by **dirtracr5** » Fri Jun 08, 2012 9:51 am

use the r2c filter wit the offset media. this gets the filter away from the "wall" of the air cleaner bottom. its worth a good amount of power on our 2bbl stuff so im sure i'd work well for you.

fwiw we found the low profile moroso tops the best in our testing.

swatson454 · Post by **swatson454** » Fri Jun 08, 2012 11:10 am

Does a base like this with a 4 x 14 element and a flat lid constitute a poor design?

jet1 · Post by **jet1** » Fri Jun 08, 2012 11:44 am

From what I can figure out based on what has been said. It appears so but I could be wrong.

Huneycutt · Post by **Huneycutt** » Fri Jun 08, 2012 12:40 pm

what is that engine in? Have you gotten that air cleaner base to fit under a hood?

swatson454 · Post by **swatson454** » Fri Jun 08, 2012 12:45 pm

Luckily it was in a full-size Blazer, otherwise I'd have been rockin' it hillbilly style

If it is indeed a poor design, that was some pretty expensive kool-aid I drank. That along with those exhaust-initiated evacs on a full exhaust

This is a good thread because there's a lot of kool-aid out there.

Shawn

#84Dave · Post by **#84Dave** » Fri Jun 08, 2012 1:30 pm

The best way to get an idea of the entry shape of the air-cleaner base/top into the top of the carb? Cut (4) wooden dowels the same length as the height of your air filter. Install the dowels between the top/bottom outside grooves of your filter base/top. Install on your carb. Then look at a side view of the assembly. The profile between the top & bottom of the assembly should appear something akin to a sideview of a head port feeding a head chamber. Sharp & greatly sloped edges/surfaces are a no-no. One can also use mold rubber to smooth the profile. Including up-and-over a choke tower, if necessary. Been there.... done that. -Dave-

nhrastocker · Post by **nhrastocker** » Fri Jun 08, 2012 1:31 pm

swatson454 wrote:Luckily it was in a full-size Blazer, otherwise I'd have been rockin' it hillbilly style

If it is indeed a poor design, that was some pretty expensive kool-aid I drank. That along with those exhaust-initiated evacs on a full exhaust

This is a good thread because there's a lot of kool-aid out there.

Shawn

Did you use any of DV's calculations or design's for the air filter?

swatson454 · Post by **swatson454** » Fri Jun 08, 2012 1:49 pm

nhrastocker wrote:
swatson454 wrote:Luckily it was in a full-size Blazer, otherwise I'd have been rockin' it hillbilly style

If it is indeed a poor design, that was some pretty expensive kool-aid I drank. That along with those exhaust-initiated evacs on a full exhaust

This is a good thread because there's a lot of kool-aid out there.

Shawn
Did you use any of DV's calculations or design's for the air filter?

Shawn

jet1 · Post by **jet1** » Fri Jun 08, 2012 2:18 pm

#84Dave wrote:The best way to get an idea of the entry shape of the air-cleaner base/top into the top of the carb? Cut (4) wooden dowels the same length as the height of your air filter. Install the dowels between the top/bottom outside grooves of your filter base/top. Install on your carb. Then look at a side view of the assembly. The profile between the top & bottom of the assembly should appear something akin to a sideview of a head port feeding a head chamber. Sharp & greatly sloped edges/surfaces are a no-no. One can also use mold rubber to smooth the profile. Including up-and-over a choke tower, if necessary. Been there.... done that. -Dave-

Ah I see

Good info.

DaveMcLain · Post by **DaveMcLain** » Fri Jun 08, 2012 2:36 pm

Another area of air filter housing design that can cause problems is when the shape messes with the bowl venting of the carburetor. I did some testing for a customer one time where we ran the air filter housing and then tested it with a 1 inch and a 2 inch spacer between it and the carburetor. 1 inch was much much better than right on the carburetor and it ran as well as having no filter but 2 inches of spacer was a disaster for power.

#84Dave · Post by **#84Dave** » Fri Jun 08, 2012 3:18 pm

Dave.............. seems to work for me......... but............ I always run a thin rubber hose off the bowl vent, upward through a hole drilled in the top of the air cleaner. For the very reason you mention. The bowl obviously needs to be at atmospheric pressure all of the time. I have seen the BSFC all over the place if the internal air flow within the filter 'disturbs' the pressure at the bowl vent entry. My little hose off the vent cleared that problem on a Holley 2-bbl. And if I run a 4-bbl, I 'jumper' the (2) bowl vents together with a section of hose and cut a 'V' in the tubing external to the air cleaner/filter top. Seems to work wonderfully! -Dave-

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