Ims rpm

[san rensho]

Originally Posted by thstone

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?