Under dirve pulleys

[doms1]

I need to replace a couple of pulleys and belt and was wondering if anyone has had experience with these??And if they make a difference??

HOLDEN VZ VE V6 3.6L 25% UNDERDRIVE BALANCER PULLEY KIT - eBay V8, Performance Parts, Car Parts, Accessories, Cars, Bikes, Boats. (end time 25-Jul-10 20:23:48 AEST)

[Surfwagon]

I use one of the 25% underdrive on my LS2 and don't find any thing detrimental.
I didn't notice any improvements (seat of the pants) but this with a few bolt ons netted me 289rwkw recently.
If you are paying someone else to fit and there is nothing wrong with your current balancer don't bother as cost most likely exceeds benefits.
If you are fitting it yourself then probably worth while even if it does only net you a couple of free kw's.

[Vt_vic]

i thought it was more for reliability not for power ive heard some people have had flat batteries due to the fact it doesnt charge them as well

[Surfwagon]

I go weeks at a time with only short trips (2-5klms) and my car is electric everything and I have had it fitted for nearly a year now and never had a flat battery.
My current battery was fitted in 07 according to receipts I have.
If people are getting flat batteries then I be looking at the accessories and how they use them before blaming the underdrive balancer.
I have all the auto stuff set to minmum and I don't leave the lights on auto all the time like some do, stereo and lights switch off as soon as you open the door.