If you're going to this level I'd be more concerned about taking weight off the crank, the weight losses achieved by properly lightening the crank and flywheel and then balancing them together are going to be much more pronounced than a lightened pulley. What RobT says about reducing ancillary speed is a very good point, but that can be solved by just turning one from ally with a smaller diamater than the original. Surely If the crank, flywheel, pressure plate and pulleys are balanced by someone who knows what they are doing then the requirement for a harmonic balancer is reduced massively anyway.
If the alternator is always running at very high speeds couldn't you put a slightly larger pulley on it to slow it down a little?
yes you could - but water pump and power steering pump would still be turning too fast on a high rev engine, so you could make 3 pully's.....or one......your choice, same end result and for F's sake, its only 20 anyhow
so if you already have a lightened flywheel and this... it will rev even quicker.. but is that good... what is the negatives..
personally I dont think there are any....only exception being the loss of a harmonic balancer which no-one seems to know exactly how it works and I know plenty people who I trust who dont run them on seriously good engines dont seem to have any problems....maybe they are necessary on production engines....dunno really
Like you say Rob I would not want to remove it on the std road engine, that sits on the motorway at the same revs for hours, however on a fully balanced competition engine with regular rebuilds its likely it would not be an issue.
hi, does any body know where i can get a bigger sized crank pulley to fit on a seat ibiza 2.0 8v gti or get one made up ????
a harmonic balancer is surely there to try and make a standard production engine as balanced as possible, cheaply, without high cost machining? When all you track guys and the like have yours professionally balanced, lightened etc u know its going to be pretty much spot on. My little theory at least! I think its right!
An inline 4 is naturally not a balanced engine, because of the very nature of its 4 cylinders firing in pulses which are not closely spaced together (compare with inline 6, where the pulses are sufficiently close to merge into much smoother power). Traditionally, weight was added to the flywheel and other rotating components, to smooth this out. A balancer shaft is a more sophisticated way of helping smoothing out the natural out of balance forces, by being deliberately shaped so as to produce an opposite force to these inherent ones. So, the racers who lighten flywheel, crank, etc are sacrificing smoothness (and ability to idle at low speed --> fuel economy in urban driving, etc) for acceleration.
I thought harmonics came into play to some extent with basically any moving and rotating part and is one of those black sciences that needs to perfectly in balance or within an acceptable tollerence to stop the engine oscillating and shaking itself to bits.?? does anyone out there know about harmonics? regarding a lightened flywheel, does it affect the torque of the engine proportionally to the power? Or would it infact loose torque with less momentum (ettect at the wheels i mean)?
Put simply: Power = torque x RPM Anything that affects torque at a particular RPM, will have the proportional effect on power.
lightening and balancing doesnt specificly give more power, more revs does so lightening and balancing helps achieve this.
If you've got lightened pistons you can remove the harmonic balancer. The harmonic balancer is dynamically balanced with the crank, so if you take it off for a test, you need to mark its position relative to the crank, for correct re-fitting.
Can you show me a picture of the harmonic balancer (and the pulleys that drive it from the crank)? Or a parts diagram, or whatever.
