View Full Version : ? about underdrive pullies

01-11-2003, 07:12 PM
does the alternator pully in an underdrive set change the output of the alternator. thanks for the help, i'm still new to this stuff.

Scott Long
01-11-2003, 07:47 PM
No it won't change the output of your alternator but it will move the peak power output farther up in the rpm range. If your alternator peaked at when your car was at 4200 rpm now it might peak at like 4900. I have heard of some peoples lights dimming while they are at idle, but hey, 15hp I think I could deal with the lights. Or just get a higher output alternator.

Bill McNeil
01-11-2003, 08:41 PM
Regarding Scott's comment to get a bigger alternator, you can get your stock alternator re-built to 130 AMPs, which should make up for the shortfall.

01-13-2003, 12:37 AM
Has anyone had cooling issues with underdrives?

01-13-2003, 02:34 PM
What type of shop would you go to to get your alt. rebuilt?

01-13-2003, 03:52 PM
A starter and alternator shop should be able to rebuild it for you check your local yellow pages. With underdrives you might also have problems with the power steering at low speeds, like parking.


Remember to remove all the balance pins from the balancer when installing underdrives. Keep a record of what pins went where in case you want to replace the stock pulley.

01-13-2003, 09:21 PM
93SC, my temperature gauge when way up when I switched to underdrives... and that was at night around 50-60 degrees... I have to think that I would have had overheating problems in stop and go in the summer... but this is AZ ;-)

01-13-2003, 10:00 PM
I can vouch for that steering problem at low speeds or trying to park, geez.. ;)

Also a lower thermo should help the heat problems.