# 1/4 mile gains with lighter flywheel and pully question



## shift_of_legend (Jun 2, 2004)

What sort of 1/4 mile gains should one expect from a fidanza flywheel and UR crank pully on a GA16DE B14


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## wes (Apr 30, 2002)

shift_of_legend said:


> What sort of 1/4 mile gains should one expect from a fidanza flywheel and UR crank pully on a GA16DE B14


hehe you cannot judge gains by 1/4 times. You can look at the dyno charts for UR pulley (2ish HP) and know that the flywheel will really not do much for your 1/4 time....


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## enjoydride (Jun 4, 2003)

wes said:


> hehe you cannot judge gains by 1/4 times. You can look at the dyno charts for UR pulley (2ish HP) and know that the flywheel will really not do much for your 1/4 time....



in my case it did cut about 1.5 seconds per lap in a 1.5 mile 12 turn road course with the JWT.


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## ghost_ryder35 (Feb 28, 2006)

thats pretty good. I heard bad things about the pulley though. Like it hurts the longitivity of the motor because of balancing or improper weight. something to those terms. Is this really a factor? And does any one else produce these pulleys cheaper, like AEM?


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## chimmike (Oct 17, 2002)

ghost_ryder35 said:


> thats pretty good. I heard bad things about the pulley though. Like it hurts the longitivity of the motor because of balancing or improper weight. something to those terms. Is this really a factor? And does any one else produce these pulleys cheaper, like AEM?


where do you hear all this crap? The Leprechaun? Care bears? Tooth fairy?

FYI, Nissan motors are internally balanced. the crank pulley does nothing to affect the longevity of the motor. A lightweight pulley simply lightens up the rotational mass of the crankshaft allowing for slightly freer revs and maybe a lil freed up hp, and slight underdriving does the same thing.

no, AEM doesn't make the pulleys, and I'd support UR anyways, they do a lot for the Nissan community that other companies would never do. 



Gains in the 1/4? from a couple mods that might free up 3-5hp? Be realistic kid. :crazy:


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## OverTake (Feb 7, 2006)

ghost_ryder35 said:


> thats pretty good. I heard bad things about the pulley though. Like it hurts the longitivity of the motor because of balancing or improper weight. something to those terms. Is this really a factor? And does any one else produce these pulleys cheaper, like AEM?



I know what your talking about. If one install a lighter pulley, it will knock the engine balancing out. I think if you change the pulley and fly wheel, Is should balance the motor. But pulley alone will put it out of balance.


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## rogoman (Dec 16, 2004)

The OEM pulley has a built-in harmonic damper not a harmonic balancer. The KA motors are internally balanced. If you look at the back side of the OEM pulley/damper, the casting is uniform meaning that the damper is a neutral balance damper. The same thing should hold true for the flywheel. Externally
balanced engines typically have an extra counterweight that's cast into one side of the harmonic damper.

If the KAs were externally balanced, everybody that runs an Unorthodox pulley would have severe vibration problems because the units have a neutral balance. So running an Unorthodox pulley and a lightened flywheel will not alter the balance of the motor.

However here's a caveat to the story. Both the OEM flywheel and front pulley are designed to act as harmonic dampers. Lightened flywheels and lightened pulleys will cancel much less harmonics causing 'possible' vibrations at certain RPMs. It all depends on how well the motor is balanced; OEM balancing will always have some degree of compromised tolerance because of mass production techniques compared to a custom balance. Some OEM balanced assemblies may be better then others.

So to make a long story short, many folks that run UR pulleys don't have any problems, while others may experience problems.


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## enjoydride (Jun 4, 2003)

I have been racing my (Japan spec) GA16 for more than 2500 racing miles and its still laping like my first day at the track.


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