[D-MAN]

What is going to give me more hp on an 05 JCW MCS

1. 16% pulley
or
2. 3% crank pulley

Would it be roughly the same?


Thanks
D-MAN

[Babes]

i reckon 15 - 17% sc pulley

[D-MAN]

Would...

JCW pulley + 3% or 4% light weight crank pulley = approximately equivalent to a 15% pulley

or am I way off mark?

[roland2003]

Yes, GTT +3% crank pulley with JCW pulley will be almost bang on equiv to -15%.
The oversize crank pulley is a a better route as :-
A) More discrete
B) JCW pulley even more difficult than stock to remove. (you will probably damage it even if you do get it off in one piece)
C) You get the added benefit of quicker spool up (similar to lightweight flywheel but less extreme)
D) No loss of belt wrap , so less risk of slip as the belt wears. You actually gain wrap on the crank pulley.
E) stock crank pulleys (particularly early ones) deform slightly with age causing some runout and possibly? some imbalance aswell. GTT pulley offers perfect balance and zero runout in either plane.
Best Regards Roland GTT

[MINI-Morgan]

Anyone thought about testing if the crank pulley causes more less drag aswell. e.g. if the supercharger were doing the same rpm with a 16% pulley or a enlarged crank which one would cause more effort for the engine to turn. Less effort means less HP lost and so means more HP total

p.s. I would recommend a larger alternator pulley too if you do the crank...

[fakesnake]

What is the difference (apart from size), between a standard crank pulley and a +3% item. I've read about the OEM crank pulley 'failing' and producing odd engine noises but the +3% item just seems to be exactly that, ie an ordinary pulley of a larger size with no 'balancing/damping facility'.

[Mini360]

Doing the crank pulley means there is no harmonic balancer ie crank bearing damage!!! do the pulley as if it blows its way cheaper to fix!

[fakesnake]

That confirms my worries -may have to do both anyway as I think my OE crank pulley is on the way out -perhaps a newer spec lighter crank pulley would be best as described in another thread. Will see, thanks

[slider]

Quote: Originally Posted by fakesnake (original)

That confirms my worries -may have to do both anyway as I think my OE crank pulley is on the way out -perhaps a newer spec lighter crank pulley would be best as described in another thread. Will see, thanks

Roland , What do you think about the risk of bearing damage following a change to the crank pulley. Im asking as you fitted one to mine about 3 weeks ago & i'm more than happy with the results thus far ....

[roland2003]

Hi, no risk atall. If removing damping /weight were to give any risk ,then every car with a lightweight /rigid flywheel conversion (Fidenza, Exedy etc) would have exploded crankshafts left right and centre, as this is MUCH more extreme 'same effect' type mod ,but at the other end of the crank.
We have cars with over 60,000miles (and highly modded) out there with GTT Crank Pulley on. ...Also cars with nearly 400bhp . Its a very well tested & proven product now.

[slider]

Quote: Originally Posted by roland2003 (original)

Hi, no risk atall. If removing damping /weight were to give any risk ,then every car with a lightweight /rigid flywheel conversion (Fidenza, Exedy etc) would have exploded crankshafts left right and centre, as this is MUCH more extreme 'same effect' type mod ,but at the other end of the crank.
We have cars with over 60,000miles (and highly modded) out there with GTT Crank Pulley on. ...Also cars with nearly 400bhp . Its a very well tested & proven product now.

thanks for that , i'm now waiting for enough funds to build up so that i can purchaed the strut brace & GTT intercooler from yourselfs to add along side the Level 1 GTT/JCW upgrade that you fitted last month...