Re: N/A carb hat or offset air cleaner opinions
[Re: radar]
#2560903
10/08/18 03:01 PM
10/08/18 03:01 PM
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Joined: Aug 2003
Posts: 43,232 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,232
Bend,OR USA
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How thick will the air cleaner element you use be? The first cast aluminum bonnet I saw was back in the early 1960 for use on a 1961 Studebaker with a factory optional McCulloch superhcarger on it. I may still have one of those for a small mouth AFB that I acquired on trade on something My message is try both and run the one you like the most
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: N/A carb hat or offset air cleaner opinions
[Re: radar]
#2560996
10/08/18 05:55 PM
10/08/18 05:55 PM
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Joined: Oct 2007
Posts: 4,209 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,209
New York
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I would begin with a "drop base" A/C bottom to take advantage of the radius shape around the opening. Extend it in all directions, especially rear (18 gauge aluminum + pop rivets, caulk it when done). What you want as result is large cross-sectional area right over the air horn. IIRC it's about 5.125" across for almost 21 In.2? You want double that (7.25" circle, 8.5" X 6.5" oval, etc. with as much height as will clear the firewall. Big internal volume (no such thing as too big) insures a large reserve of still air (intake velocity is traded for pressure), in which the venturis draw as if they were in free air. Any form of screen: big restriction.
Boffin Emeritus
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Re: N/A carb hat or offset air cleaner opinions
[Re: polyspheric]
#2561014
10/08/18 06:30 PM
10/08/18 06:30 PM
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Joined: Mar 2009
Posts: 2,467 Sydney,Australia
tex013
top fuel
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top fuel
Joined: Mar 2009
Posts: 2,467
Sydney,Australia
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I would begin with a "drop base" A/C bottom to take advantage of the radius shape around the opening. Extend it in all directions, especially rear (18 gauge aluminum + pop rivets, caulk it when done). What you want as result is large cross-sectional area right over the air horn. IIRC it's about 5.125" across for almost 21 In.2? You want double that (7.25" circle, 8.5" X 6.5" oval, etc. with as much height as will clear the firewall. Big internal volume (no such thing as too big) insures a large reserve of still air (intake velocity is traded for pressure), in which the venturis draw as if they were in free air. Any form of screen: big restriction. just curious . No screen ? What would cause these to be such a problem ? I have a similar issue though I run a dominator . Height clearance , no more than 3 1/3 ", no wider than 14". I run a screen with airplate sealed to hood sorry for the interjection 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: N/A carb hat or offset air cleaner opinions
[Re: radar]
#2561085
10/08/18 09:36 PM
10/08/18 09:36 PM
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Joined: Mar 2009
Posts: 2,467 Sydney,Australia
tex013
top fuel
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top fuel
Joined: Mar 2009
Posts: 2,467
Sydney,Australia
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So no go for plan B? Haha
Thanks for the responses. I wish somebody knew more about that $100 hat if it is a tuning nightmare I will steer clear. Going as big and tall as possible totally makes sense. The paper filter should slow down any air flow enough to prevent a lot of turbulence above the vents and butterflies- as long as it’s a big enough ‘filtered plenum’ it won’t get ugly and windy in there in a bad way?
My third idea came from the dollar store and is not the best one but for $6 worth a try for ABA testing... WOOHOO !! that's mine ! Tex
Last edited by tex013; 10/08/18 09:39 PM.
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: N/A carb hat or offset air cleaner opinions
[Re: radar]
#2561086
10/08/18 09:37 PM
10/08/18 09:37 PM
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Joined: Oct 2007
Posts: 4,209 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,209
New York
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Questions are always appropriate. The wire forming the screen is a miniature telephone pole (exterior surfaces are not actually smooth-n-shiny), and causes aero drag much worse than you would suspect. The openings must be microscopic to keep anything dangerous out, and they're the worst on flow. A screen opening large enough to reduce drag only stops birds. The screen area has to be like 2-3 times the air horn area NOT to reduce air speed and CFM. The usual curved dome is wayyy too small. If the rules actually required it (and forbade a filter) my guess would be to use the 14" common base and land a screen 1/2-dome 14" OD, 7" tall on it - that's 308 in.2 or 15 times the air horn area. Other 1/2-domes ranked by surface area: 5.125" wide (stock AH): 41 In.2 8" wide: 101 In.2 10" wide: 157 In.2
Boffin Emeritus
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Re: N/A carb hat or offset air cleaner opinions
[Re: radar]
#2561090
10/08/18 09:41 PM
10/08/18 09:41 PM
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Joined: Oct 2007
Posts: 4,209 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,209
New York
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Better hats are available.
Boffin Emeritus
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Re: N/A carb hat or offset air cleaner opinions
[Re: polyspheric]
#2561095
10/08/18 09:50 PM
10/08/18 09:50 PM
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Joined: Mar 2009
Posts: 2,467 Sydney,Australia
tex013
top fuel
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top fuel
Joined: Mar 2009
Posts: 2,467
Sydney,Australia
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Better hats are available. maybe just a bigger diameter screen/ sieve 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: N/A carb hat or offset air cleaner opinions
[Re: radar]
#2561149
10/08/18 11:16 PM
10/08/18 11:16 PM
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Joined: Jan 2003
Posts: 17,884 S.E. Michigan
ZIPPY
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 17,884
S.E. Michigan
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Oh ok. Well give it a whirl. I Don't know if that's a good design but I'm all for testing ideas. Maybe just rough it in to see what happens.
I've seen a ring welded to a flat tray holding a late model type flat filter. While that'd fit, I have no idea how it would flow.
Rich H.
Esse Quam Videri
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Re: N/A carb hat or offset air cleaner opinions
[Re: radar]
#2561278
10/09/18 04:21 AM
10/09/18 04:21 AM
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Joined: Sep 2015
Posts: 1,096 Australia
ozymaxwedge
super stock
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super stock
Joined: Sep 2015
Posts: 1,096
Australia
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Search "holley flame arrestor"
1963 Plymouth Max Wedge 1971 Barracuda
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Re: N/A carb hat or offset air cleaner opinions
[Re: radar]
#2561293
10/09/18 08:59 AM
10/09/18 08:59 AM
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Joined: Jan 2005
Posts: 4,243 Charlotte, North Carolina
sgcuda
master
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master
Joined: Jan 2005
Posts: 4,243
Charlotte, North Carolina
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How about the plastic air horns that were on the Dakota's and 1500's late '90's early 2000's. I'll get a pic of mine later. It locates the filter forward of the throttle body.
[image][/image]
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Re: N/A carb hat or offset air cleaner opinions
[Re: radar]
#2561338
10/09/18 11:51 AM
10/09/18 11:51 AM
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Joined: Feb 2010
Posts: 1,645 Phila. Pa.
Mattax
top fuel
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top fuel
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
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Resistance to flow through screens increases with air velocity. IIRC its exponential. Screens can be used a airdams if properly supported. As far as turbulance and flow. Don't forget how important it is to protect the bowl vents. Preferably the bowl pressure is staying the same (Holley) and certainly don't want erractic unpredictable fluctuations. Skim through this thread for ideas - photos of various ways to do it. https://www.tapatalk.com/groups/racingfuelsystems/bowl-vents-t15.html
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