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930turbo 930turbo is offline
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Join Date: Jul 2006
Location: Valrico Florida
Posts: 199
Yes, the effective - or dynamic - compression does change under boost. It is not directly proportional to the increase in absolute pressure as the effeciency of the engine will cause a reduction. More air forced through the same size holes (vavles, intake, etc.) will result in less air overall. This is one of my favorite links for approximate calculations;
http://www.turbofast.com.au/javacalc.html
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'77 930 turbo Garretson I/C 1 BAR spring, (2) '82 Triumph Bonneville Royal Wedding Edition
Past rides: '74 914 1.9 liter twin plugged track car, '83 928S, '87 924S, '75 911S w '78 ROW 3.0, '72 911T, '70 911T and various other insignificant domestic examples. Happiness is a grey tailpipe! Turbo lag......it's worth the wait!
Old 07-19-2007, 11:54 AM
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