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  • 2 weeks later...
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  • Member For: 16y 11m 8d
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When I had my Na it made a great difference any weight off your crank will allow the engine to free spin more, so the engine will rev quicker, only bad thing is you lose low down pulling torque but I never noticed it, any weight of the pulley and flywheel will make the engine rev quicker. I think you would gain 10kw to 15 kw max, I have one I don't look back

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  • Member For: 14y 18d
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youll find with turbos theres not really any gains to be had... I would think the cons would outway the pros on this one.

  • I see a red door and I want to paint it black
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  • Member For: 22y 4m 16d
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  • Location: Perth, WA

When I had my Na it made a great difference any weight off your crank will allow the engine to free spin more, so the engine will rev quicker, only bad thing is you lose low down pulling torque but I never noticed it, any weight of the pulley and flywheel will make the engine rev quicker. I think you would gain 10kw to 15 kw max, I have one I don't look back

I would seriously doubt that any power increases will be seen from modifying the pulleys, certainly not from a weight reduction point of view, as plastic factory units are quite light already. Underdrive pulleys may provide a little gain by spinning your alternator and a/c slower, but only at the detriment of performance.

As spinning energy is only a fraction of a fraction of the reciprocating energy lost by moving the rods and pistons up and down, there is nothing to be gained, except for the 'bling' factor, which is why I have red alu pulleys on my engine, nothing more, nothing less :blind:

Edited by Ninka
  • 4 weeks later...
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I would seriously doubt that any power increases will be seen from modifying the pulleys, certainly not from a weight reduction point of view, as plastic factory units are quite light already. Underdrive pulleys may provide a little gain by spinning your alternator and a/c slower, but only at the detriment of performance.

This I agree with, but the std balancer weighs 4.2kgs and the Powerbond Underdrive weighs 2.8kgs FACT!

I proved this years ago .. forget the underdrive hocus pocus and focus on 1.4kgs off the reciprical mass .. this is where the benefit comes from .

I have fitted many and seen first hand PB's at Willowbank shortly after... Daz

*EDIT*

I cant find the video I wanted to back up my findings so this will have to suffice until I do...

Edited by XR6menace
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  • Member For: 22y 4m 16d
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Well, my impression was that we were talking about the PULLEYS and not the balancer.

Altering the weight of the balancer can introduce a whole lot of other problems, especially on a straight six where the dampening of torsional crank stresses are critical, so though it may provide short term gain, just make sure it is suitable for the application, or you may end up with a broken crank.

By the way, I added a billet flexplate for my last engine build, and its somewhat heavier than the flimsy Ford deal (I dont have the exact number), but engine came out more responsive on the other side of the build, so as a minumum, a couple of kilos makes negligable difference to responsiveness.

Edited by Ninka
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Just for the record NO customers have ever broken a crank and I have run a 200shot through my bottom end before No6 rod let go...

The Underdrive has more than proven itself the Typhoon even picked up 7rwkws on the dyno and considering the Plazmaman cooler covers the whole radiator the temp never goes over a 1/4 with the 71* stat ...

Lighweight pulleys made of alloy ?

I misunderstood the question obviously the plastic parts weigh next to nothing BUT repco now sell metal pulleys as replacement...

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  • Member For: 22y 4m 16d
  • Gender: Male
  • Location: Perth, WA

Just for the record NO customers have ever broken a crank and I have run a 200shot through my bottom end before No6 rod let go...

The Underdrive has more than proven itself the Typhoon even picked up 7rwkws on the dyno and considering the Plazmaman cooler covers the whole radiator the temp never goes over a 1/4 with the 71* stat ...

Lighweight pulleys made of alloy ?

I misunderstood the question obviously the plastic parts weigh next to nothing BUT repco now sell metal pulleys as replacement...

Well, let's just agree that the original question has been addressed.

I already posted and placed a picture of the Repco pulleys elsewhere, so let's not make this an argument over balancers and their relative effect, trust me, IT WILL GO ON FOREVER and I really would rather stop here :biggrin:

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