Standard SC pulley atm

 

I forgot there is also the Forge 11.5% reduction supercharger pulley...

 

So here is an interesting thought. Does installing a 2% crank pulley make good sense for the cooling benefits, especially if you are doing a supercharger pulley or doing something else to increase power? Increasing the coolant flow rate by a small amount can increase cooling efficency and offset some of the heat increase due to power increase. The 2% pulley will spin the water pump faster increasing flow and cooling, as well as reduce the workload in the engine since the pulley is lighter. I know people talk about the theoretical vibration issue but that is covered elsewhere. Spinning the water pump slightly faster should be good as long as you don't spin fast enough to create aeration or caviation, which could create localized hotspots and also reduce cooling efficency. There are a lot of things that happen when changing the pulleys and spinning the SC faster, such as increased heating of the SC and increased heating of the intake air, so cooling is an important consideration, hence better intercoolers. Until someone puts an engine on a bench with the proper sensors attached we won't know for sure what the results are, but I think the benefits increased water pump speed should be considered.

See here for more detail on cooling issues:
http://www.arrowheadradiator.com/14_...utomobiles.htm

 

this is a good read, especially since i'm noticing a ton of squeal on my undersized belt using a 19% pulley and have been thinking about doing the 17% + 2% crank.... do we have a list of comparable systems besides the safe 15% +2-3% crank / 16% + 2% crank?

i'm not going to give up on my 19% total reduction, i've been driving it HARD for roughly 30K miles with no problems using the same belt - yikes, definitely should have changed it sooner since i kept a secondary one in the car in case of emergency! never had any slipping, nothing broken, no [stock] crank pulley damaging at all.... so here comes question time!

i have a high-powered stereo system in my car as well as tons of lighting mods, powering an Optima Yellow-top battery and Xstatic BATCAP.... is an alternator pulley a good idea with my setup?

if i did 19% + 0% lightened crank pulley, is there still a need for the alternator pulley?

if i did 17% + 2% crank, what size alternator pulley would i need (if any)?

is the 0% crank as effective in unsprung weight reduction as the 2% - another way, will both crank pullies lighten unsprung weight by the same amount, or is one lighter?

 

A crank pulley is not unsprung weight. It's attached to the engine, which is obviously sprung. The only benefit of using a lighter crank pulley is for throttle response, and the 05-06 crank pulley is already so light that going lighter doesn't make any difference. Tune your car if you're looking for throttle response.

 

Alas I have an overweight 03 pulley on my 03 MCS.... I've read your other posts and thoughts about adding an aftermarket crank pulley, but what's the problem with doing a 0% lightened crank pulley? as for throttle response, having new motor mounts, new throttle body, AGS, and the tuning i've got.... i'm pretty good so far! just thought to get rid of the extra weight effectively from a lightened crank pulley where i've added about 150lbs total to the car via the stereo system might be a good idea!

 

Rustyboy155 have you done this yourself and is this your own personal experience?
I have an 05 MCS and changed the crank pulley to a 2% and it makes a big difference not only snappier response but also more hp.