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Old 12-21-2020, 01:30 AM   #24 (permalink)
hayden55
Master EcoModder
 
Join Date: Dec 2010
Location: USA
Posts: 1,171

Sport Utility Prius - '10 Toyota Prius II
90 day: 52.98 mpg (US)

300k Sequoia 4WD - '01 Toyota Sequoia Limited 4wd
90 day: 20.19 mpg (US)
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Quote:
Originally Posted by serialk11r View Post
I think the way to think about crank harmonics is that they are the residual \angular vibrations in the crank. Most of that energy isn't going to make it into moving the car if it's connected directly to the wheels, since it'll just rock things back and forth in a perfectly rigid drivetrain. In real life, it just goes through the sprung hub, dual mass flywheel springs (if applicable), gear lash, etc.

The downside apart from the crank being under more stress is that ignition timing goes off. I think it's pretty normal to observe more power from a damped engine on a dyno because the ignition timing variance is reduced.
I remember the Honda/JDM guys losing horses on the dyno going to their lightweight all aluminum pulley kits. Makes sense. Steeda (OEM contractor with Ford) uses a harmonic balancer for their underdrive pulley kits for the mustang.
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