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Old 01-15-2009, 03:17 AM   #17 (permalink)
annoyingrob
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Join Date: Aug 2008
Location: Calgary, AB
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Quote:
Originally Posted by saitotiktmdog View Post
Doesnt that depend on the wastegate. I believe mine has that capability. There are two vac hook ups on mine. One above and one below the spring diaphram.
If you're really creative, you could hook a vacuum accumulator to the top port to lower opening pressure, but that would be really hard to control. In general, the lowest pressure a wastegate can operate is the spring tension applied to it. His best bet is to replace the wastegate with the stock one.

Another interesting, but likely insignificant fact, the 22R-TE ECU actually cuts fuel at a specific airflow, not at a specific pressure. Saying it will cut at 14psi may hold true for the stock turbo, but with a bigger flowing turbo, boost cut could occur much lower, say 8psi.

The best way to raise boost cut is to first install a larger AFM (Like from a 5M), then install proportionally larger injectors. This is done quite frequently in the Supra world, upgrading the 7M-GTE AFM with one from a 1UZ, then upgrading the 440cc injectors to 550cc. The problem is that you MUST make sure you are increasing each equally to ensure you don't run too lean. If in doubt, err on the side of larger injectors.
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86 SR5 Turbo pickup Fiberglass bed, Fiberglass Fenders.
91 1.5JZ GT40 Supra.
77 Celica Liftback. (WTB: 20R Carb!)
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