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Old 06-02-2009, 11:19 AM   #45
Scooby Specialist
Member#: 4498
Join Date: Feb 2001
Chapter/Region: NWIC
Location: Portland, Oregon
WRX H6-3.0 Turbo


Originally Posted by socalLGT View Post
Nice test Jeff. I've got an 08 STI at the shop that I'll be finishing this week with Cossie heads/cams, Cossie manifold and a .82 GT3076R. I hope to see some larger gains with this combo than you saw. IIRC, your car is running the Cobb SD patch. Wouldn't you expect to see the AFR's lean out a bit if VE was improved by the manifold? Afterall, higher VE would translate to increased airflow for a given boost level. That would lead to an SD fueling car running leaner.
I switched to my MAF tune for this.. SD would add another variable. You are correct that in SD I suspect the car would be a bit leaner, which would probably make more power. That is one of the critical reasons you have to have good logging and compare the data with care. Had the car been in SD mode, it might have gained power everywhere, but only because of the change in AFR. (obviously if the AFR changed it would do so only as a result of VE.. so there would be more to the story).

Originally Posted by karmasi16 View Post
i hate to ask... did you do the manifold test on a stock car with a proper tune to see what just the manifold would yield?
No, but I would welcome you to give that test a try. I would be surprised to see any real gains, but then again I could be wrong!

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sponaugle is offline   Reply With Quote