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Old 12th October 2006, 08:40 AM   #209 (permalink)
Hugh Keir
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Join Date: Jul 2001
Location: Aberdeen Scotland
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Quote:
Originally Posted by sleepyfox View Post
Great post Hugh - though this confuses me more: If this is a harmonic problem or due to 'belt flex' then why does it manifest itself more in a higher gear? Surely it should be the same at the same engine revs no matter what gear you are in?
sleepyfox,

As far as I understand it, the cam belt flex is induced by the resistance of rotating the cams + crankshaft flex.

As the engine becomes more loaded under high boost at high RPM the crank will flex more with each combustion which causes more inaccuracies in cam and ignition timing.

Removing the ignition timing aspect of the above by triggering the ECU from a non cam belt driven source is a large part of the solution.
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