Lightened Underdrive Pulleys......Its ok to change the Crank!!!
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Lightened Underdrive Pulleys......Its ok to change the Crank!!!
3) "Isn't my stock crank/eccentric pulley a balancer, harmonic/torsional, or vibrational damper?"
A common misconception is that factory crank pulleys on certain vehicles are harmonic dampers. The fact is, on todays late model cars the factory crank pulley is designed to reduce NVH (noise / vibration / harshness), which does not affect crankshaft or bearing life. These are noises and vibrations from the engine compartment that may travel into the cabin of the vehicle when the engine is running and the stock crank pulley is used to reduce NVH for the occupants (similar to the use of resonators in the intake to quiet intake noise). We do not manufacture crank pulleys that replace or eliminate a damper in applications where the factory crank pulley is an actual harmonic damper (such as 90 degree V engines).
I pulled this off of http://www.unorthodoxracing.com/faq_pulleys.html.
A common misconception is that factory crank pulleys on certain vehicles are harmonic dampers. The fact is, on todays late model cars the factory crank pulley is designed to reduce NVH (noise / vibration / harshness), which does not affect crankshaft or bearing life. These are noises and vibrations from the engine compartment that may travel into the cabin of the vehicle when the engine is running and the stock crank pulley is used to reduce NVH for the occupants (similar to the use of resonators in the intake to quiet intake noise). We do not manufacture crank pulleys that replace or eliminate a damper in applications where the factory crank pulley is an actual harmonic damper (such as 90 degree V engines).
I pulled this off of http://www.unorthodoxracing.com/faq_pulleys.html.
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Rep Power: 0 do not change the crank pulley! you will blow your oil pump out! a few guys at my local tuning shop said that the crank pulley should only be used for hardcore racing, because of that fact.
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Rep Power: 0 << do not change the crank pulley! you will blow your oil pump out! a few guys at my local tuning shop said that the crank pulley should only be used for hardcore racing, because of that fact. >>
What is the process by which a lightened crank pully destroys your oil pump?
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Rep Power: 0 You just have to match it up with a lightened flywheel!!
The theory is that a crank pulley disrupts the balance of the crank, therefor wearing the bearings and causing harmonics and unwanted vibrations that are hard on the bottom end.
Im gonna leave mine stock.
The theory is that a crank pulley disrupts the balance of the crank, therefor wearing the bearings and causing harmonics and unwanted vibrations that are hard on the bottom end.
Im gonna leave mine stock.
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From: Car Audioville, Quebec, Canada
Rep Power: 0 Think about this for a minute okay.. The Crank pulley is always under tension and being pulled in one direction from the Belt. see..therefore any weight or "balancing" it may have doesn't affect diddly squat as the tension on the crank pulley varies.. Turn the steering wheel.. the power steering pumps adds pressure, therefore pulling on the crank more.. he he pulling crank [IMG]i/expressions/laugh2.gif[/IMG][IMG]i/expressions/laugh2.gif[/IMG]..Turn on the A/C and deffoggers, crank your system.. takes more power to turn the alternator.. more tension throwing the pulley further off balance..oh my[IMG]i/expressions/face-icon-small-frown.gif[/IMG][IMG]i/expressions/face-icon-small-frown.gif[/IMG]....
in 90 Degree v-block engines this comes into effect more because tension is equal accross the crank pulley from the Timing gears and belt tensioners...
Hmmm I know it I Rule![IMG]i/expressions/moon.gif[/IMG][IMG]i/expressions/moon.gif[/IMG]
[IMG]i/expressions/beer_yum.gif[/IMG][IMG]i/expressions/beer_yum.gif[/IMG]
Cheers
Mohawk
P.S. If you want a sound syste.. DO NOT EVER GET UNDERDRIVE PULLEYS!
in 90 Degree v-block engines this comes into effect more because tension is equal accross the crank pulley from the Timing gears and belt tensioners...
Hmmm I know it I Rule![IMG]i/expressions/moon.gif[/IMG][IMG]i/expressions/moon.gif[/IMG]
[IMG]i/expressions/beer_yum.gif[/IMG][IMG]i/expressions/beer_yum.gif[/IMG]Cheers
Mohawk
P.S. If you want a sound syste.. DO NOT EVER GET UNDERDRIVE PULLEYS!
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Rep Power: 0 If all this worrying is keeping you awake, then I would say DONT get em....HOWEVER, so far, in 5 years of use, UR has not had ONE engine failure......If a light pulley is bad, then a HEAVY one should be great....if you want to go by that reasoning. I wonder why race engines have such light pullies???? Hmmmm....
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