Underdrive pulley

[SOPES]

Has anyone installed the 25% underdrive pulley ? What brand ? did you notice any increase in power ? Is it true the engine revs quicker ? I just wanna know if its worth the investment ?

[c0ncEpT]

I had one on my last LS1 car. No idea if it made a difference. Car ran pretty good for what it was tho.

Mine was a Powerbond bought through SDPC.

[ruckusz28]

I had a 2 piece march under drive kit on my old 4th gen. Had the smaller alt pulley and the crank.

Arguably one of the better mods that I did to the car. No real issues aside from the Voltage. Pulled a lot harder. At idle with the a/c on, headlights, fans, the voltage would hit the 12s. Had to tune the idle up to 1,000 and that resolved the issues. Don't plan on running any major electronics after the swap.

Also, I highly recommend upgrading the vehicle's ground points with some 4 gauge wires or larger. I picked up another volt just from that alone.

[limited360]

I had a 2 piece march under drive kit on my old 4th gen. Had the smaller alt pulley and the crank.

Arguably one of the better mods that I did to the car. No real issues aside from the Voltage. Pulled a lot harder. At idle with the a/c on, headlights, fans, the voltage would hit the 12s. Had to tune the idle up to 1,000 and that resolved the issues. Don't plan on running any major electronics after the swap.

Also, I highly recommend upgrading the vehicle's ground points with some 4 gauge wires or larger. I picked up another volt just from that alone.

Thanks for the follow up comment on 4 gauge ground wires. I was wondering if there was an issues as see my volts drop of significantly at idle on stock pulleys with no electronics going.

[DETROITMUSCLE]

I don't have any extra electronics aside from some gauges so I didn't have any voltage issues but I added a larger Lid/MAF setup and an ASP underdrive pulley and netted a 20rwhp gain, not sure which had more effect but I was happy with the results.

[SOPES]

That helps, I have the lid now, I plan on putting on the 25% pulley. Im trying not to go to crazy. I dont want to sacrafice driveability for a bit more power

[BP_Z28]

Driveability?


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[DETROITMUSCLE]

Driveability? I have a practically full bolt on LS w/pulley..and I need moar powa

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unaffected aside from a voltage drop.

[SOPES]

I think Im gonna do just the crank pulley, I plan on putting a bass tube in eventually

[Nocooler]

Powerbond on mine - gained nothing measurable at the track.

[hoogiesngrinderz]

I think Im gonna do just the crank pulley, I plan on putting a bass tube in eventually

This makes me think....did my BBK setup come with a larger alternator pulley?

[SOPES]

yeah Ive seen the 2 pc kit on ebay I just want to keep the alternator semi happy

[ruckusz28]

Correct me if I'm wrong, but by reducing the alternator pulley circumference it should spin faster.

[c0ncEpT]

Correct me if I'm wrong, but by reducing the alternator pulley circumference it should spin faster.

True. Reducing the drive pulley slows everything down, reducing the driven pulley speeds the unit up.

[SOPES]

Wouldnt putting a diff pulley on the alt. defeat the purpose of the underdrive crank pulley ?