Carb Airbox, Input appreciated... |
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Carb Airbox, Input appreciated... |
stepuptotheMike |
May 16 2009, 07:04 AM
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#1
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medium pimpin Group: Members Posts: 565 Joined: 4-September 06 From: Charlotte, NC Member No.: 6,769 Region Association: South East States |
So I have Weber 44s on my car. When the installation was done by a previous, previous owner, there were some aspects that were less than detail oriented. Items such as the following:
-Fuel Vapor lines from the front (car is a 73) just dump into the engine compartment. Assuming this contributes to fuel smell in car. -Crank vent is basically a hose with a tiny air filter on it, suspended over the engine case... this leads to oil film all over. - No head breather ports. Heads were never drilled/tapped for them, but I don't think my venting is adequate and it's causing oil leaks. - Carbs in general are just loud. I want to hear some throat when I get on it, but don't need it all the time. So in reading through various threads (especially the ones on the breather setups folks have posted recently) I started thinking about how I could solve all of these problems in 1. Creating a legal setup that would pull the fuel vapors and case/vents into the carb intakes..... and quieting things down a little bit. So I thought about creating a single airbox that would install over the combined carb setup. Ideally, I would think plastic would be the medium of choice, but I have no clue where I would start.... so then I started thinking about fiberglass. Granted, I've never really built anything with glass, but it's fairly cheap and if it doesn't work I figure I'm only out my time and a few bucks. Plus I learn something in the process. I figure I could use techniques similar to those that the custom speaker box guys use to form shapes and build the box. This would just be thinner. So I came up with the following crude drawing to illustrate kind of what I'm talking about. I would appreciate thoughts on this concept. Shoot holes in it as you see fit. Been down this road before? Know somebody that tried something similar? Thanks in advance.... Mike |
azbill |
May 16 2009, 01:32 PM
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#2
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Member Group: Members Posts: 455 Joined: 26-July 04 From: Glendale, Az Member No.: 2,403 Region Association: Southwest Region |
I am using 3" tubing and have found that the Quite Air is somewhat restricted. When I get the production model done I will dyno the car again and state what the difference. The price has not been determined.
Yes it is designed to complement the Sidewinder throttle control. But, I am selling them as separate units. Bill Shaffer |
r_towle |
Jun 12 2009, 11:43 AM
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#3
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Custom Member Group: Members Posts: 24,585 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
I am using 3" tubing and have found that the Quite Air is somewhat restricted. When I get the production model done I will dyno the car again and state what the difference. The price has not been determined. Yes it is designed to complement the Sidewinder throttle control. But, I am selling them as separate units. Bill Shaffer Back of the napkin math makes me think about the tubing size. A single 40mm barrel on a dual weber is close to the 2 inch tubing size of 50mm So it makes me think that for a system to work properly and have no restriction, you would need at least a 3 inch intak tube from each carb (80mm is 3.14 inches) and then at your merge portion you would need 6 inches. None of my math factors in the timing of each intake pulse, but I think if you step up to 3 inch tubing, you will probably be alot better off. Rich |
VaccaRabite |
Mar 18 2011, 08:23 AM
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#4
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En Garde! Group: Admin Posts: 13,456 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
I am using 3" tubing and have found that the Quite Air is somewhat restricted. When I get the production model done I will dyno the car again and state what the difference. The price has not been determined. Yes it is designed to complement the Sidewinder throttle control. But, I am selling them as separate units. Bill Shaffer Back of the napkin math makes me think about the tubing size. A single 40mm barrel on a dual weber is close to the 2 inch tubing size of 50mm So it makes me think that for a system to work properly and have no restriction, you would need at least a 3 inch intak tube from each carb (80mm is 3.14 inches) and then at your merge portion you would need 6 inches. None of my math factors in the timing of each intake pulse, but I think if you step up to 3 inch tubing, you will probably be alot better off. Rich Huh, feel free to doublecheck me, but I think 2 inch to the carbs and 3 inch at the join would be fine. This is how I figured it: Area of a circle = Pi*r^2. If we assume that the carb in question has a 32mm main vent (which would be as big as most of our cars would ever have), that means each barrel has an area of 803mm^2. Both barrels would then be 1608mm^2 And all four barrels would be 3216mm^2 A two inch circle has an area of 1994mm^2 Therefore, a 2 inch tube should be plenty for 1 bank of carbs. A three inch circle has an area of 4415mm^2, which should be fine for both banks. So, not taking into consideration drag from going through the air filter, a 2 inch tube to each carb bank and a 3 inch inlet should not cause restriction. Obviously this would not work for a 6, just a 4. Zach |
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