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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Just thought, I suspect the BMW has active cam timing and can vary overlap by rpm and load.

Might be it can work with the lower residual cylinder pressures that come with a divided turbine system and get more aggressive with valve overlap at times.

I can not see how BMW or anyone could have made a lower volume manifold. Further, putting the WG in the turbo eliminates the volume of the WG circuit.

(Maybe a VAT)

I now understand why an equal length header has more even cylinder temps. More even pressures when the exhaust valves closes. This also allows a motor to be run closer to the optimum timing and AFR with out fear of having a cylinder or two detonating.
Old 06-06-2010, 06:15 PM
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