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Discussion Starter #1
Has anyone fitted a light weight undersized crank pulley. Looking into sourcing one at the mo. I know AutoLusso do a kit for £175.
Would like to know the benefits of someone actually running one thanks.
 

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I would think they only have effect when changing gear allowing the engine to slow more quickly between shifts. If you think about it when in gear the engine has to rotate the flywheel, clutch and gearbox. Then the diff, driveshafts and wheels to move the car. I can't see how shaving a few grams off can have any affect. The standard pulley also probably balances the crank to some extent.
 

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Discussion Starter #3
I would think they only have effect when changing gear allowing the engine to slow more quickly between shifts. If you think about it when in gear the engine has to rotate the flywheel, clutch and gearbox. Then the diff, driveshafts and wheels to move the car. I can't see how shaving a few grams off can have any affect. The standard pulley also probably balances the crank to some extent.
Ok, so from what I gather the pulley is 10% of the crank weight and can be reduced by more than half, and balancing is only really important on V6 engines not the TS and if the pulley is turned instead of forged.

Quote from a friend on facebook - I put one on mine, easy to fit, lets the engine come up the rev band a little quicker, not a big increase, same principle as a lightened fly wheel.

Seems to me it might be an easy upgrade.
 

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Ok, so from what I gather the pulley is 10% of the crank weight and can be reduced by more than half, and balancing is only really important on V6 engines not the TS and if the pulley is turned instead of forged.

Quote from a friend on facebook - I put one on mine, easy to fit, lets the engine come up the rev band a little quicker, not a big increase, same principle as a lightened fly wheel.

Seems to me it might be an easy upgrade.
I agree with Spankdanny, I can't believe you will notice a difference as the pulley is only 10% of crank weight. As Spankdanny says, the engine still has to move the same weight of car! This falls in the same category as suspension braces, strut braces, roll over hoops and other shiny bits, there will always be someone who falls for shiny bits i guess.
 

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The standard pulley is heavier and has a rubber section to it to damp out the harmonic vibrations of the crank. On full race engines that are rebuilt often it's not a problem. On a road car it's probably not worth the risk of damaging big end and main bearings. Also lightened undrive pulleys will spin the alternator, power steering and air con pumps more slowly which might not be ideal.
 

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I have one. It's good. Check the net for factual research rather than opinion. No rubber pulley on the Twinspark.

Sent from my LG-H815 using Tapatalk
 

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Ok, your right, I got it out of the shed to look and I'd never noticed the thin rubber part before.

However, the facts about fitting a lightened pulley remain. They work with no detrimental effects. Get one and try it, you'll love it.

Sent from my LG-H815 using Tapatalk
 

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A nice informative article Spankdanny, which appears to be based on the experience of the writer of the article. Personally I wouldn’t risk it for the sake of a few BHP. I had always assumed that Alfa spent a not inconsiderable amount of money developing their engine, and like most manufacturers have added a damped pulley ( as well as a counter balance shaft on the twinny). This probably to damp out damaging vibrations, hence the name. I guess it depends on how long you want your engine to last, and how smooth you want it to be, but if a chap in a shed with a lathe has managed to produce such an excellent item, I would ask myself why aren’t all of the engine manufacturers fitting them, because if they did this bloke in a shed would be a very rich man, and the major car manufacturers would be fitting them as standard, which as far as I know, they are not. Let’s face it, this type of pulley would be much cheaper to manufacture than the damped ones, and if manufacturers can save one fifth of a penny anywhere they will. Having visited a couple of car plants, and looked at their ‘lean’ methods, they would have picked up on this damperless, smaller, underdriven pulley long ago. I would spend the £175 on taking the wife away for a night, much more worthwhile :)
 
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