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Old 12-02-2010, 12:15 AM   #64 (permalink)
dcb
needs more cowbell
 
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Quote:
Originally Posted by Old Mechanic View Post
Do a coast down test of a vehicle.

In high gear with standard engine. Highest loss
In neutral. No loss related to engine
Pull the plugs to eliminate the compression.
Pull the head to eliminate valve train losses.

You would have to push the car to speed in tha last two tests.
unfortunately that doesn't really answer the question... when the pistons (and some fraction of the connecting rods) are accelerated and decelerated energy is lost, question is how much. I did figure it out on the valves once and it was a trivial amount of power, assuming you aren't approaching redline.
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