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Old 12-26-2010, 03:38 PM
charlief1 charlief1 is offline
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Default Re: Better turbo design

Quote:
Originally Posted by kenmosher View Post
I will be very interested in seeing how this works in a draw through capacity! Looking at the maps, I'm wondering if about the vacuum "signal" to the carb and whether it will be able to keep up with the added flow?
Thanks for the comments Ken. The one thing most people don't know about the carb is that it's rated at 800 CFM and GM restricted the back two barrels to reduce flow. They did this by keeping the top butterfly from opening fully. The biggest restriction is the plenum. The throat will need to be modified so it will be opened up some just for this reason.

Warwagon (Adam), my friend Aj in NM, and myself have been playing with this for over 3 years now. Aj's been able to use a 750 Holley spread bore successfully and he was using the original 78-79 system, but he didn't use the stock manifold.

One other thing I forgot to add is depending on which system you use will make a difference. The 78-80 use a separate ESC that operates independently and the power valve circuit is routed through a pressure sensing mechanical valve to cut the vacuum signal to the power valve so it goes full rich until the engine has less than 2 lbs of pressure in it. According to GM they called it a PECV valve (power enrichment circuit valve) but it's sometimes called a PEVR valve.

You cannot use a normal Quadrajet carburetor with this system. It is specialized and very scarce and has different fuel/vacuum circuits in it.

The 81-83 system uses a CCC carburetor that's controlled by the computer and it has an ESC similar to the fuel injected engines.

Last edited by charlief1; 12-26-2010 at 06:55 PM.
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