Light Crank Pulley/-s/c From Gm Parts Direct

[csealy_31]

Has anyone installed a lightwieght crank pulley and had trouble with the lower end or general engine consuming itself??? The original pulley is supposed to be a harmonic dampening type. Is this true? I know the 2.4 has balancing shafts, but before I install a lightweight pulley, I would like to know that it will at least last me about 60K miles!!
Also has anyone ever ordered parts from GM parts direct. Supposedly they have the 2.4 s/c for $1995.00-goto http://www.gmpartsdirect.com/ and enter in part#12498660. It's a hell of a deal, I'm just not to sure since they are about 500 less than everybody else!

[fusion]

I've just gotten the RSM lightened Crank pulley!!

Man, it's WAY better and lighter than the original crank, which is freakin' heavy and made of cast iron.

I hear that the 2.4L engines have a vibration damper which isn't part of the original pulley.... although, the original pulley does seem to have some rubber on it.

Sof far, i've felt some nice gains and smoother/quicker acceleration - not to mention a much smoother engine. The only thing that decreased slightly is the voltage levels, by approximately 0.5v to 1 volt during heavy usage.

OOOh, nice find on the S/C! That package will give you 180HP from 150HP.
If ya double that and then some, you can get the RSM Vortech S/C, which gives you up to 210 - 235 HP depending on the stage. And then there's Turbos, but they're still more of a custom jobby ;)

Fusion

[`2000redalero]

where's a product description for the s/c?

[Oldsman]

I have the UR pulley and it is a good mod. No issues at all.

But if you are going to go to the S/C then you will not want it because it will hurt your boost.

[csealy_31]

didn't consider the boost loss when switching out the pulley. the s/c is supposed to boost a stocker up to 190 hp. Do you think the larger throttle body would help? I'm hoping to get up to the 200-220 mark. I've got the 62mm RSM body on now and it helped big time with the CAI.

[Final-Reality]

The larger throttle body will definately help with the supercharger, so will an exhaust header and a free-flowing 2.5" exhaust. That should easily put you in the ~200-210HP range.

But if you get an "underdrive" crank pulley, then you are also underdriving the supercharger, meaning you're lowering boost pressure. So I wouldn't recommend that. In fact there are smaller pullies available for the supercharger, as small as 2.5". The stock supercharger pulley is 2.8" and gives you something like 5psi of boost (using the stock crank pulley, that is). The 2.5" pulley should net you around 9-10psi of boost on a good day, and with the aformentioned throttle body and exhaust system, you should be happily cruising with 225-230HP...

[fusion]

......and with the S/C in mind, RSM also has just a lightened crank pulley at 14oz.
not an underdrive. :ph34r:

[ShortysTRM]

that sounds sweet...how much does the stock pulley weigh?

[Oldsman]

close to 5 lbs. actually i think it was 4.7 lbs

[ShortysTRM]

HFS :blink: :D

[fusion]

The guy at RSM showed me the underdrive pulley, and i was like nice...
....then, after the install was done, he handed me the stock iron pulley, and i was like
OMG.... sooo frickin' heavy

[ShortysTRM]

are there any huge benefits from the lightened pulley? I have always heard that for every 6Lb's of rotating mass you take away from the driveline you gain like 1% HP, but I dunno how accurate that is. Faster revs? Less vibration?

[Oldsman]

definitely faster revs and i could notice a tiny little bit on the top end.

they say the UR pulley gives ya a 5 hp increase.

read these

http://invision.aleromod.com/index.php?showtopic=120

[fusion]

Yeah, i would think that a 5 HP gain is pretty high - especially with no other major mods.

I've seen gains of 0.2 seconds easy off my 1/4 mile times.... still stuck in the 16s.. barely!