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  #11  
Old 12-25-2010, 11:39 PM
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Thumbs up Re: Better turbo design

Thread is being "stuck". Obviously of great value to the carbed turbo TR community.
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  #12  
Old 12-26-2010, 12:35 AM
charlief1 charlief1 is offline
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Talking Re: Better turbo design

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Thread is being "stuck". Obviously of great value to the carbed turbo TR community.
Thanks for the Christmas present Scott. This is the only "sticky" in the before black section but I will put more info on here and hope you find it sticky worthy.
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  #13  
Old 12-26-2010, 11:12 AM
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Default Re: Better turbo design

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?
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  #14  
Old 12-26-2010, 12:33 PM
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Default Re: Better turbo design

Congrat's Charlie!
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  #15  
Old 12-26-2010, 03:38 PM
charlief1 charlief1 is offline
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Default Re: Better turbo design

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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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  #16  
Old 06-08-2011, 10:02 PM
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Default Re: Better turbo design

so if the carb is special and i don't have one, is it safe to say that i could set up an fi system easier than finding the right carb? mine is a 79 4bbl. i have the computer but no carb. i only have a few that work with my BBB430
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Old 06-09-2011, 12:07 AM
charlief1 charlief1 is offline
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Default Re: Better turbo design

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Originally Posted by cowboydan View Post
so if the carb is special and i don't have one, is it safe to say that i could set up an fi system easier than finding the right carb? mine is a 79 4bbl. i have the computer but no carb. i only have a few that work with my BBB430
The carb is specific for the 78-80 designs but the 81-83 is a CCC carb so you can use any of the the E4ME carbs on the later designs. You can also make a a carb for the earlier cars by using a 4MC or 4ME carb top and an E4ME base. It has to be drilled for an extra tube for the power valve control but it's not that big a deal.

Visit www.beforeblack.net and you can read up on the different designs. Another site you might want to look at http://members.fortunecity.com/petesbuick/ . Pete outlines several different solutions on such parts as the PEVC valve and the turbo control unit.

One other thing you might look at is the post I did about the earlier carbs and what they look like. Pretty simple and I've out lined how to make one of the earlier carbs from parts.

http://www.turbobuick.com/forums/bef...bo-design.html
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Old 06-21-2011, 11:26 AM
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Default Re: Better turbo design

ok. i reread the entire thing. i understand why you chose the specific year components. i was wrong in the year engine that i have( 79) it's all 78.

in the last part where you enlarged the outlet on the turbo foot, how much did you have to remove to have the connection smooth? would it be possible to enlarge the inake hole on the intake manifold?
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  #19  
Old 06-21-2011, 11:54 AM
charlief1 charlief1 is offline
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Default Re: Better turbo design

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Originally Posted by cowboydan View Post
ok. i reread the entire thing. i understand why you chose the specific year components. i was wrong in the year engine that i have( 79) it's all 78.

in the last part where you enlarged the outlet on the turbo foot, how much did you have to remove to have the connection smooth? would it be possible to enlarge the inake hole on the intake manifold?
Take a look on the other board for "finally got some time" and "All turbos are not created equal". This will give you a better idea of the turbo and the car overall. There's lots of mods that you can add to the 78 but the low port heads will not work as well as the 79 up high port heads.

The plenum can be enlarged to improve flow and the inlet of the turbo is enlarged to the same size so it removes some restriction.

As far as the foot, all I did was move the mounting feet to make it mount up to the intake. The rest of that area isn't enlarge at all.
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Old 08-21-2011, 11:51 PM
charlief1 charlief1 is offline
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Default Re: Better turbo design

Thought I'd offer some pics of the stock VS the modified turbo and plenum. You really don't get the difference until you see them side by side. The modified turbo is much bigger in comparison. What I've had questioned is opening the plenum as much as I did. What most people don't realize is that the spread bore carb has small primaries which enhances the low RPM response. The small primaries allow for more velocity of the air fuel mixture, and until the need comes up for the secondaries to kick in, it's pretty fast. This helps torque on the bottom and when the secondaries open, you get the big boost off the back 2 barrels.
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