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Lightened Flywheel VS Crank Pulley

Discussion in 'General Tech and Maintenance' started by B16RacerN2NR, Jan 7, 2007.

  1. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    Hope this is the correct forum...

    There is something that I still can't figure out. I've tried searching every where but to no avail...

    I understand why a light weight flywheel is good/better but what I haven't gotten the answer to is why changing over to a lighter crank pulley is bad. I figure they are doing the same thing. I'm sure changing the size if the pulley itself might cause some damage but i don't see how it can cause damage just if it's lighter... am I missing something here?
     
  2. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Harmonic balancer
     
  3. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    I'll look in that section...

    Cel, that still doesn'r explain how you can change the weight on one side of the crank but you can't/shouldn't on the other... :shrug:
     
  4. K2e2vin

    K2e2vin Senior Member

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    Guess what's attached on the crank pulley side of the crankshaft? Yep, oil pump.
     
  5. MikeBergy

    MikeBergy Blah blah blah....

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    It has next to nothing to do with weight reduction. The reason most don't change the pulley is because most aftermarket crank pulleys don't utilize a harmonic damper, which is the main reason for retaining the stock pulley.

    Also, consider the real reason for changing the flywheel out for a lightweight unit - lower moment-of-inertia. Look at the MOI for a disk.

    List of moments of inertia - Wikipedia, the free encyclopedia

    The formula is Iz = m(r^2)/2
    Reducing the weight on a flywheel that is nearly 12 inches diameter will much more directly affect the MOI of the assembly than a reduction of weight from a pulley that is only approx. 6 inches in diameter. There is a factor of 4 decrease for the flywheel weight reduction in comparison to an identical weight reduction on the crank pulley, assuming those are the correct diameters. The MOI directly affects the engine's ability to rev quickly; it is not solely dependent on the weight of the rotating mass but also the distance the mass is from the rotational axis. There's the short answer for why it is more effective to go with a lightweight flywheel and leave the pulley stock.
     
  6. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    ah ok... that's more understandable...thanks
     
  7. 1goldteg

    1goldteg 1st Gen CRX lover

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    How do you guys feel about the N1 crank pully from Honda? I would think it would be engineered correctly for the application...

    Mike
     
  8. E_SolSi

    E_SolSi Member of the 20 nut club Moderator VIP

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    the N1 pully still does not have the pressed rubber core for absorbing vibration
     
  9. TurboMirage

    TurboMirage YEEAAAHHH VIP

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    get your stock flywheel machined...
     
  10. E_SolSi

    E_SolSi Member of the 20 nut club Moderator VIP

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