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Old 09-21-2012, 06:10 PM   #50 (permalink)
serialk11r
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spyder2 - '00 Toyota MR2 Spyder
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Quote:
Originally Posted by smokey442 View Post
Open waste gate at low throttle to reduce exhaust back pressure. I'd try retarding the cam 5deg. keeping exhaust valve closed longer extracting more usefull work from still relativly high cylinder pressure. Later intake closing lowers vacume. Pull an 8"hg depression into crankcase via intake vacume.
Okay so I didn't see anyone talking about these, but I think these are good places to pick up efficiency. Low boost turbos tend to have ****tier backpressure under cruise, if you can get an electronically actuated wastegate for them that would help. I imagine in the real world you only relieve a small amount of pressure but you have a large displacement engine so a small amount of pressure adds up to a lot of loss.

If I'm not mistaken the LS1 has "single cams" (1 for each cylinder bank with exhaust and intake lobes on it)? In that case retarding the cam doesn't work since that would increase the overlap and interfere with combustion stability. You might want to look into a regrind that cuts off a little of the overlap but maintains the same intake closure. If possible having the intake valves close even later is "ideal" in some sense, probably increases your top end power too.
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