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lfeather's avatar
lfeather
Explorer
Aug 27, 2015

7-14 psi turbo boost when engine compression brake engaged

With, as always, zero torque and 256 mpg as shown on silverleaf. Anyone have any ideas why this would occur? I wouldn't think that turboboost should activate with engine compression brake engaged? TIA
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JetAonly's avatar
JetAonly
Explorer
Aug 29, 2015
A compression brake forces the engine to do work. The air exhausting the engine is hotter than the air entering it by the amount of work done in compressing the air. Adiabetic heating. The turbine continues to extract work from the exhaust gases which produces boost.

Fuel, after all, is just a way to heat air so it expands.

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