Air cleaner contoured entry criticality?
#2593057
12/17/18 06:14 AM
12/17/18 06:14 AM
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Joined: Jan 2003
Posts: 3,943 Melbourne.....Oz-land
Moparmal
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OP
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I’m fabricating a cold air base to use at the track. First - I have seen the Engine Masters video but it doesn’t address the issue of contoured ‘air bell’ profile. A crucial omission by those guys imho. Moving on - The 65 A990 cars ran a dual contoured air bell cold air system, HOWEVER, the 67 ‘023’ Super stockers ran a base with a much more aggressive throat ‘entry’ (see pic) This raises the question how important an ‘air bell’ type entry is? Any thoughts or experiences?
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Re: Air cleaner contoured entry criticality?
[Re: Moparmal]
#2593093
12/17/18 11:58 AM
12/17/18 11:58 AM
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Joined: Oct 2007
Posts: 4,206 New York
polyspheric
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master
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New York
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The hardware bridge across the top was known to be a mistake 70 years ago. 2 small coil springs can hold the plate down from underneath. The radius shown has reached the point of vanishing returns (very little gain above 3/8": Vizard), but IDK if the filter itself is too close to the entry; another inch added front and rear might help. The lowest pumping loss/highest CFM for a given entry has a 3/8" (or more) submerged floor, and the bell has a 3/4 (270°) rollover radius. All of this may be insignificant on anything but a maximum effort engine. Keep in mind that air movement in that can is not continuous, it occurs in bursts.
Boffin Emeritus
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Re: Air cleaner contoured entry criticality?
[Re: Moparmal]
#2593184
12/17/18 03:27 PM
12/17/18 03:27 PM
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Joined: Dec 2005
Posts: 11,524 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,524
Fulton County, PA
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My theory is a radius is always better than a sharp edge. I've always used a bell on the pan or a K&N stub stack if available space prevented the bell.
If the results don't match the theory, change the theory.
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Re: Air cleaner contoured entry criticality?
[Re: Moparmal]
#2593284
12/17/18 06:27 PM
12/17/18 06:27 PM
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Joined: Mar 2009
Posts: 2,458 Sydney,Australia
tex013
top fuel
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top fuel
Joined: Mar 2009
Posts: 2,458
Sydney,Australia
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I think you are overthinking it Mal . Unless you are going full in . Of course a curved entry is best if possible . Mine is simply a chrome air cleaner base , though i trimmed it a bit for extra clearance . Why i only have a screen for racing I know some decry a screen but it works for me
Tex
New best ET 10.259@129.65 . New best MPH 130.32 Finally fitted a solid cam, stepped it up a bit more 3690lbs through the mufflers New World block 3780lbs 10.278@130.80 . Wowser 10.253@130.24 footbraking from 1500rpm Power by Tex's Automotive
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Re: Air cleaner contoured entry criticality?
[Re: Moparmal]
#2593338
12/17/18 07:57 PM
12/17/18 07:57 PM
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Joined: Oct 2007
Posts: 4,206 New York
polyspheric
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master
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New York
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Depending on the engine size and VE, that screen may be completely neutral. As engine size goes up it will reach a point where it's a restriction. If you attached a vacuum cleaner hose to the opening, and tried it with and without the screen, then hold a smoke generator at different places around the screen, you might see something. The vacuum engine will change pitch is loaded more, or an ammeter?
For a screen to be (nearly) harmless, use as many of these as possible: 1. larger squares (yes, it will only trap small rocks) 2. finer wire (even .5mm instead of 1/32" is better, especially if area is small) 3. larger dome diameter 4. farther away from entry vertically 5. no bracket
Boffin Emeritus
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Re: Air cleaner contoured entry criticality?
[Re: polyspheric]
#2593577
12/18/18 03:14 AM
12/18/18 03:14 AM
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Joined: Jan 2003
Posts: 3,943 Melbourne.....Oz-land
Moparmal
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The hardware bridge across the top was known to be a mistake 70 years ago. 2 small coil springs can hold the plate down from underneath. The radius shown has reached the point of vanishing returns (very little gain above 3/8": Vizard), but IDK if the filter itself is too close to the entry; another inch added front and rear might help. The lowest pumping loss/highest CFM for a given entry has a 3/8" (or more) submerged floor, and the bell has a 3/4 (270°) rollover radius. All of this may be insignificant on anything but a maximum effort engine. Keep in mind that air movement in that can is not continuous, it occurs in bursts. Polyspheric - Re the hardware bridge - do you have a pic or can you describe where you’d attach coil spring restraints? Also, I’m not following your comment about the 3/8 radius - are you referring to the depth of the flanges?
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Re: Air cleaner contoured entry criticality?
[Re: Moparmal]
#2593729
12/18/18 01:33 PM
12/18/18 01:33 PM
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Joined: Oct 2007
Posts: 4,206 New York
polyspheric
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master
Joined: Oct 2007
Posts: 4,206
New York
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Pick a spot on the floor of the pan, left and right sides. Small hole, 10-24 screw, small tab (1 hole for the screw, 1 for the coil) underneath Coil hooks to the tab Pulls down, attaches to manifold bolt, existing linkage, any convenienet point easily reached for service
In some cases, there's enough compression height and resistance in the foam that the hood keeps the AC in place.
The flat floor of the pan is 3/8" lower than the carb's entry radius, carb will pull air from behind it. Radius in cross-section is 270 degree arc.
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Re: Air cleaner contoured entry criticality?
[Re: Moparmal]
#2593742
12/18/18 01:55 PM
12/18/18 01:55 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Minimum number of bends.. try to keep the air flow as straight as possible.. I made a base and used a volosity stack for mine... the stack is 5" tall to the radius then into the carb.. lots of air space above the carb
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Re: Air cleaner contoured entry criticality?
[Re: Moparmal]
#2594123
12/19/18 05:48 AM
12/19/18 05:48 AM
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Joined: Jan 2003
Posts: 3,943 Melbourne.....Oz-land
Moparmal
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Ok, thx for the advice, I’ll post a pic of my fabrication shortly. I think it meets the objective
67 RO23 clone with 6.1 SRT Hemi and dual quads. Soon to have Drag Pak induction and Throttle body.
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Re: Air cleaner contoured entry criticality?
[Re: BradH]
#2608831
01/19/19 12:22 AM
01/19/19 12:22 AM
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Joined: Jan 2003
Posts: 3,943 Melbourne.....Oz-land
Moparmal
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Looks nice. You can get the flame-retardant foam that Moroso includes w/ their air pan kits separately from the whole kit. That's what I used to seal my plate to the hood. Thx, I’ll look into it. First testing will be on a dyno vs a Hemi oval dual quad air cleaner with K&N filter.
67 RO23 clone with 6.1 SRT Hemi and dual quads. Soon to have Drag Pak induction and Throttle body.
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