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Tippy Tippy is offline
Chain fence eating turbo
Join Date: Dec 2008
Location: Austin, TX
Posts: 8,715
Sizing ITB's for boost and IC configuring?

So, I know the conventional wisdom is bigger the better for NA applications where all out max hp is required (until point of diminishing returns), but what about boosted applications?

I have a Carrera 3.2 (3.4) with stock intake port sizes (42mm IIRC) and I believe the OEM 3.2 intake are the same throughout until the runners meet the log parts of the manifold (assuming here?).

So, question is, do you run like a 44mm ITB (account for butterfly area diminished to get back to 42mm total area) or something like 50mm plus?

My brain is saying something like 44mm for good driveability (high velocity) but I see so many ITB's out there far larger making me have doubts.

Also, trying to figure configuring existing IC I have to work or if I'll have to go with a totally different end tank arrangement?
Cory - turbo'd '87 C3.2 Guards/Blk, 3.4, 7.5:1 CR P & C's, soon to be 993SS cams and GSXR 750 ITB's fed by 964 intake, Borg-Warner S366 turbo @ 1.4 bar, Treadstone full bay IC, TiAL F46 WG, HKS 1 1/2" BOV, twin 044 pumps, MegaSquirt 2 (v3.57 board) w/EDIS, Tramont wheels (285's rr, 225's frt), Big Reds frt, 993 rr., tower brace, MOMO wheel
Old 03-16-2014, 08:12 AM
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