do ali bottom pullys make much difference to the bhp on a 20xe

[jonnyd61]

do ali bottom pullys make much difference to the bhp on a 20xe ???

[Benn]

Makes no difference. All the do is turn the alt.

[Stuart]

Does the normal pulley have some rubber in it? If so then its a harmonic damper.... which the ali ones wont have and WILL ultimately damage your crankshaft.

[dgbnova#1]

Yes it does have rubber inner core

[Benn]

Does the normal pulley have some rubber in it? If so then its a harmonic damper.... which the ali ones wont have and WILL ultimately damage your crankshaft.

Really? I didn't know that.

[Stuart]

It's a harmonic damper, it takes out ske of the shock vibrations from the crank. Removing the damper will shorten the life of the crank

[mowgli]

it might save a fraction of a hp if you are using a lower geared pulley. that is all

[8valve-craig]

It's a harmonic damper, Removing the damper will shorten the life of the crank

Plenty of Vaux engines came with no rubber in the aux pulley. Lots are still running fine.

Out of interest, which part of the crank would you expect to be affected?

[mowgli]

or in other words, gm lowered the expected engine life

[Stuart]

Usually snaps round the journals if it goes.

But then people dont seem to care or consider harmonics lol

[burgo]

I watched a david vizard documentary and he said harmonic balancers are more for the valve train. Reason being people spend all this money on lighter valves and uprated springs yet without a balancer then at certain engine rpm the engine vibrations/resonance cause the valves to float causing a nice dip in power. Or something lol

[mowgli]

/\ have you read about the balancer fitted to the cosworth dfv? it is a remarkable device

http://img248.imageshack.us/img248/4599/cosworthdfxinkcopy.jpg

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQ_8XBPZrwooIpCMESkAms3lgbdC3HUY d6s6BrwvA6gTDV9zycV