Old Aug 11, 2012 | 04:51 PM
  #916  
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Karl
Norris Motorsport
 
Joined: May 2003
Posts: 3,437
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From: Derbyshire
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I actually agree with Danny, it certainly is'nt horrendous. I would suggest from looking at the bowl size on the pistons that the C.R is actually higher than stated. I would suggest around 7.6:1 with those size valve cutouts. 14 degrees ign is too advanced for that compression at 2 bar boost in the mid range rpms. Something around 8 would be correct, at 14 degrees you'd be at the onset of det, albeit not immediate engine failure casuing det. At 7.6:1 catastrophic det usually occurs at around 15 degrees at 2 bar boost at the infamous danger zone of 5500rpm. As this engine was running near to 14 degrees of advance, I would suggest (because no one can say with 100% certainty) it was within the danger zone.
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