View Full Version : underdrive pulleys??

06-21-2006, 11:56 PM
alrighty everyone, i work at a machine shop and have unlimited access to the tools needed and all the help i need to make what i need. First on my list is the underdrive pulleys for my 91 toyota celica GT. If anyone has any idea of where to get the dimensions or the actual dimensions of it?? any help is greatly appreciated.

Thanks Jerry

06-23-2006, 12:17 AM
Buy one from a wrecker and bust out the calipers and micrometer.

06-23-2006, 12:56 AM
are the overdrive pulley's smaller?? thats really all i need to know

06-23-2006, 03:05 AM
yes they are, thats how the work. they are a smaller pulley that then in turn spins your accessories at a slower rate, making your engine devote less power to the accessories. How much smaller i dont know.

06-23-2006, 03:37 AM
Unorthodox makes them already. Is there a reason why you are looking to fab them?

06-24-2006, 04:57 AM
no real reason, i just want some custom stuff on my car, you know so i can say that i have somethin i made on my own, it will put a smile on my face

06-24-2006, 05:00 AM
Totally understandable and kudos! I just wanted to make sure you knew about the ones they make already. Good luck!

06-25-2006, 01:00 PM
gracias amigo :) now i cant find the specs anywhere, i know its probably a top secret info withheld by the companies. Does anyone know which pulleys u make smaller and which pulleys you make bigger??? thanks for the help guyz,


06-26-2006, 02:44 AM
The pulley the engine turns directly should be smaller, all the others could be made bigger if you wanted too.

Same principle as gears. (You probably can work out the ratios the same, using pulley diameter).

Driving (constant RPM) --> Driven (RPM depends on pulley ratio).

Big --> Small = turns the small pulley faster and more load on driving pulley

Small --> Big = turns the big pulley slower and less load on driving pulley.