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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,267
i never said boost is regulated by rpm or tps.
and btw what is "tps" throttle position sensor or throttle position switch... seems it should just be tp for throttle position.

i understand everything about long duration cams, late cam timing, and the intake ram effect they create at high rpms. also short duration cams and how they work making more torque at lower rpms from less overlap... and variable cam timing and lift, but that came much later starting with the nissan 300zx in 1989 and honda after that, and then even later on the germans finally caught on with it.

anyway, the wastegate valve which is opened by intake air pressure doesn't actually regulate boost. it is regulating exhaust manifold pressure by leaking exhaust gasses out to atmosphere which in turn regulates the speed or rpms of the turbine wheel in the hot side of the turbo.
more exhaust pressure means more exhaust gas flow which spins up the turbo to higher rpms which is directly attached to the compressor wheel in the cold side of the turbo which when spinning faster blows more air. if that air has no where to go (a given engine rpm and throttle position holding it back) it builds up pressure as it is being compressed and that is what we call boost.

i understand how compressing air QUICKLY heats it up because the friction between the air molecules during that compression creates heat.

in the end i think we are talking about two different paremeters of the whole sequence and i get tired of plucking away at a keyboard trying to make my thoughts clear so i'll just leave it at that.

that said, i have a K27HFS on my car... or actually it is on a UPS truck heading west right now to get new oil seals and possibly new bearings installed.
i had a K27 7006 on my car before that so i know the difference from experience.
i've also worked on 962's, 935's, and 934's... never got to drive one though other than in a parking lot.
Old 07-15-2008, 12:38 PM
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