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      01-28-2013, 10:16 AM   #5
BMWM.D.
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Drives: E90 335i & C6 Grand Sport
Join Date: May 2009
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Quote:
Originally Posted by BMWN54tech View Post
N54's are designed from factory to have slight pressure at idle IF the wastegates are closed. The software keeps the wastegates open during idling. Change that and you have boost. Small turbos bro.
Actually depends on the software level. The later cars have the wastegates closed at idle for less turbo lag. My early N54 (1/07) has the wastegates open at idle, as I have the lovely 6mm-pin early turbo design that likes to rattle.

Regardless of wastegate position, the bypass valves should be pulled open by the vacuum in the intake manifold at idle. BMW definitely didn't engineer the car to have positive pressure in the manifold at idle and cruise.
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