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Input Needed on turbo 4 barrel


Cjarloz

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Basically you need to eliminate the power valve (it is a back fire problem any way on older carbs) and re-jet 2 - 3 size up to compensate the power valve loss. You also need to change fuel floats to non-collapsible type, and seal vents of the fuel bowls.

 

I'm using a power valve for my 20 year old 750 DP on Twin Turbo 383 Chevy without problems.

If you plug the power valve you better increase the jet size by 8-10.

When you say "seal vents of fuel bowls", do you mean float bowls? If so, then you will be unable to pressurize the bowls for fuel flow.

I prefer a full carb enclosure for turbo carb applications and believe it is easier to setup than a bonnet, however, carb access is more difficult. But I'm not familiar with the space required for full enclosure on the 2.8 L.

As far as carb size is concerned, another important factor is air/fuel ratio. I have seen 2.8 L Z's at the Import Drag Races with 750 DP's for blow through and draw through systems run in the 11 second range.

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  • 2 weeks later...

the fuel pressure will always have 3 to 5 psi above the boost pressure or the fuel will be shut off by the float needles.the bonnet runs pressure down the bowl vents.this will cause it to lean out on boost.holley carbs are a pain.by the time you get this working you will wish you went efi.nothing like changing jetting on a laptop.no gas leaks and no jets to buy.

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  • 2 weeks later...

Bill,

If you go to page 5 of the Turbo / Supercharger forum, you will find pics of my Z under the "Twin Turbo 383 Chevy" post. I'm currently installing lower compression ratio pistons into the 383 engine and am taking pics of engine, exhaust system and induction. I will attempt to post the pics, in a few weeks, in the "album" gallery.

Hanns

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Guest znow white

the yellow carb turbo z was for sale on ebay I dont remember how much it was sold for but I know it was a late turbo tom setup with 290-300 hp....

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