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Old 12-02-2012, 03:37 AM   #40
Gnarly Adventurer
Joined: Sep 2011
Location: Halifax, Nova Scotia
Oddometer: 133

This engine was built to run at lower speed for a long time with more usable, less intimidating power/torque delivery.

Originally Posted by OldPete View Post
Intake valve closing in the most important valve event.
Close it early and low rpm torque is up but high rpm breathing/HP is limited.
Close it late and low rpm torque is down but high rpm HP figures go up.

With late closing, compression can be increase because effective c/r is low at low rpm.

With state of the art ECU, fuel & ignition timing can be such that a late closing intake can still have good low rpm grunt.
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