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jcc911 jcc911 is offline
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Join Date: Jan 2004
Location: Milwaukee, WI
Posts: 3,263
Help me understand C/R, Detonation, Etc.

Hey guys,
What I am trying to understand is, Is there an equation which correlates Boost to increased C/R?
What I am also trying to understand is what is too high of a C/R before detonation sets in or is it more complicated to that?

As many of you know I am trying to Turbocharge my SC engine again... but I want to make sure I do it safely.
The plan is to use a Euro 930 CIS, The 993 Y and HEs, along with factory IC/ Airbox etc.

The plan is to keep the boost between 0.5-0.7 bar, will the factory 930 IC be sufficient to prevent detonation, or again is it more than that?

If the Turbo Carerra had 7:1 C/R, and did not use an IC, what was the CR underboost?

I saw an engine for sale which was Turbocharged and had a 10.5:1 CR how is that operarted safely, when there is such concern for later SC engines and even my 78 with a C/R of 8.5:1 (I beleive).

I know it is is a lot of questions, but TIA for educating me.
Jeremy C.
Why's he calling me meat? I'm the one driving a Porsche. (Bull Durham)
----Nothing is far away in this car!----
-1978 911 SC TURBO, Minerva Blue Targa 965 update.
-2008 550i M-Sport
Old 02-21-2009, 04:09 AM
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