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TBI to carb swap fuel percolation/heat soak prevention

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Old Jul 5, 2014 | 09:39 AM
  #1  
Mortorq's Avatar
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From: Hoffman Estates Il
Car: '88 IROC T5 Vert ‘13 Vette
Engine: 305 TBI
Transmission: T5
Axle/Gears: 3:08
TBI to carb swap fuel percolation/heat soak prevention

With an occasional-use, pump gas, mild, 5 speed, L03 TBI swap to an L31 carb, would the following steps help stem the common fuel heat soak/percolation issues I read so much about here?

I've searched and found factory fixes such as, a fan on the carb, a booster electric fuel pump etc. that didn't work until everything went EFI.

I have a carb & manifold, no money or time to do the EBL, Moates, or the equivalent excellent science of fast355.

Sooooo........ would the following be a feasible?

A) Cowl induction hood to help exhaust hot underhood air
B) L69/HO-style dual snorkle air filter plumbed to the front of the core support, factory -style
C) Insulated 4309 regulator to carb gas line
D) carb heat shield w/ phenolic spacer
E) 180`F thermostat and a slightly lower (20`F maybe?) setpoint for the fan on switch
Thanks
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Old Jul 5, 2014 | 10:38 AM
  #2  
Vader's Avatar
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Re: TBI to carb swap fuel percolation/heat soak prevention

I would try Items D and E, and in that order, and Item B as just a generally good idea for cold air intake. So long as the fuel is percolating in the carb bowls and not in the fuel line (vapor locking) keeping the heat from the carb might be most effective.

Item A might not be as good an idea as it might appear on the surface. A cowl hood doesn't necessarily provide a place for cool air to enter, but always provides a convenient place for hot air to escape. You can't alter physics, and the hot air will rise, potentially creating a chimney effect which will simply assure that the carburetor and intake are the LAST things to cool down until the engine is cooled.
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Old Jul 5, 2014 | 10:45 AM
  #3  
Mortorq's Avatar
Thread Starter
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15 Year Member
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Joined: Dec 2006
Posts: 271
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From: Hoffman Estates Il
Car: '88 IROC T5 Vert ‘13 Vette
Engine: 305 TBI
Transmission: T5
Axle/Gears: 3:08
Re: TBI to carb swap fuel percolation/heat soak prevention

Originally Posted by Vader
I would try Items D and E, and in that order, and Item B as just a generally good idea for cold air intake. So long as the fuel is percolating in the carb bowls and not in the fuel line (vapor locking) keeping the heat from the carb might be most effective.

Item A might not be as good an idea as it might appear on the surface. A cowl hood doesn't necessarily provide a place for cool air to enter, but always provides a convenient place for hot air to escape. You can't alter physics, and the hot air will rise, potentially creating a chimney effect which will simply assure that the carburetor and intake are the LAST things to cool down until the engine is cooled.
Thanks Vader, appreciate the advice.
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