Turbo manifold tube size? Also B34 VS B35 head?

Discussion pertaining to positive pressure E28s.
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Loupoz
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Joined: Jul 02, 2018 7:49 AM

Turbo manifold tube size? Also B34 VS B35 head?

Post by Loupoz »

Hi. Im in the planning stages of a turbo build, and i want to make my own manifold. Power goal is 600-700 hp at the crank. What size tubing should i use? Im ofc planning on some relatively thick wall (min 2.5 mm). But what should the inner diameter be? Anyone know the cross sectional area of a M30 exhaust port? Or just general dimensions?

Also i think i read somewhere that a B35 head (E34) flows better than a B34 (E28) head. Is there any point in searching for that as a starting point? Im gonna have it CNC ported Anyway.
tschultz
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Joined: Mar 01, 2009 8:58 PM
Location: Denver, Colorado
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Re: Turbo manifold tube size? Also B34 VS B35 head?

Post by tschultz »

B35 head unless you are are oversizing the valves in the B34 head in which they will be the same. At that power level it would seem you will need a custom intake and a beefed up head to be able to rev it out (rocker arms, cam, valve springs, porting, largest valves possible, 5 angle grind, MLS headgasket or similar). Likely pistons as well...

Maybe for that power level a split pulse turbine housing and and even length runners with as large as possible 3"+ exhaust.

More importantly do you have a plan for how you will tune/operate it?
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