Thread: Ims rpm
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Old 07-11-2014, 12:05 PM   #7
san rensho
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Quote:
Originally Posted by thstone View Post
The intermediate shaft is driven by the crankshaft via a duplex roller chain with a transmission ratio of 0.67:1 (24 teeth on the crankshaft and 36 teeth on the intermediate shaft).


Porsche Workshop Manuals > Boxster (986) F6-2.5L (1998) > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Auxiliary Shaft > Component Information > Description and Operation
Can't argue with your math, but it doesn't make sense. The IMS is run off the crank and drives the cams via a chain drive. Since the cams operate at 1/2 or 2x (can't remember which) the crank rotations to ensure proper timing, .67/1 ratio would mean the cams would be wildly out of sync with the crank. What am I missing?
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