Porting 930 Intake

[sigchuck]

Hi guys, I have posted previously about my plans to turbocharge my 83 SC using 930 parts (manifold/CIS/exhaust, etc.).

My factory SC heads have a 35mm intake port, and the factory 930 port is 32mm (I think that's correct on both, but in any event, the SC port is larger than the 930).

Since I would need to port the plastic 930 injector blocks, I'm considering ordering a billet set from Turbokraft (32mm on manifold side and 35mm on head side).

As these will be custom injector blocks, I could also do 35mm on both sides and port the 930 intake to match.

My concern is (i) diminishing the value of the 930 intake should I ever choose to remove it, and (ii) is the additional cost of porting the intake worth the horsepower gain? With respect to the second point, would this result in any noticeable gain?

My goals are a relatively low boost (.5 bar) setup that hopefully won't immediately ruin my stock 915. Thanks for your help guys!

[T77911S]

the 930 intake is not worth that much in my opinion.

port the intake and get the billet from TK and port them and don't look back

[Alan L]

Chris at TK would tell you the same.
Alan

[TurboKraft]

The stock plastic injector blocks aren't that reliable and crack top & bottom, even at a stock 32mm. Their absolute limit is 36mm (which is why that's where Ruf and Andial stopped) but this makes them less reliable still on a performance engine.

Which is why we manufacture aluminum injector blocks with phenolic insulators -- so you can port them up to 40mm (usually the practical limit of the CIS manifold) or larger (custom manifold applications).

If we were building the engine, we would open your manifold to 35mm or larger to get the most airflow through it possible.

If you're concerned about future value and saving all take-off parts (your stock 32mm heads), then source any used 1978-94 Turbo intake manifold and modify it.

[Kraftday]

Here is one for sale ported. With this you could match a billet tappered port injector manifold from TurboKraft.

$1250 shipped for pro job.

These manifolds are magnesium and their design helps with quick response.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F22 3118847807