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Old 07-02-2018, 03:33 AM   #53
Tcoat
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Quote:
Originally Posted by nikitopo View Post
Depends how you want to present the data and the kind of the racing application. If you do a 5th gear dyno, then Fluidampr might give the theoretical 2hp top gain cause of the less vibration. However, on small race tracks or mountain roads you rarelly work on high gears. You are interested much more on corner exit speed acceleration mainly on 2nd or 3rd gear. Over there a lightweight pulley will have the advantage cause of the less rotational inertia. On 5th gear this advantage is lost and it doesn't show on a dyno because the RPMs are rising much slower. Additionally, as very well pointed by SuperTom in most racing applications you don't stay all time in high RPMs. Maybe NASCAR might be an exception, but these cars are not relevant with this area if you don't swap a motor.
The minuscule advantage that a light weight pulley offers is lost the second the car is put in gear. Any gear. As soon as the engine has to rotate a flywheel, clutch disc, transmission gears, drive shaft, differential, axles, wheels and all the shafts, joints and other moving parts involved the fact that you saved a pound in rotating mass in a pulley isn't even noise much less measurable.
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