Underdrive Pulleys

[JMS'sMSP]

Has/does anyone know how hard it would be to change the pulleys on our car (2001 MP3???) I want to get the ones from Indigo but I have never changed pulleys before and it looks like a big pain in the a@#

 

[20ESGUY]

They're not hard at all, just time consuming because of the lack of space. Just a tip if you need some more room to work with take the right side motor mount off, support the engine with a sutable jack and just lift slightly, that'll bring the top side up to where you can get to it a little better. Besides underdrive pullies are well worth the money and the time.

 

[wildman]

hey 20 i'm new to game, y r pulleys worth the money and time?

 

[20ESGUY]

Underdrive's are worth the time and money becuase they lower the necassary torque the engine has to use to drive the accessories. You can figure on an average engine that every extra accessory, such as alternator or a/c compressor, robs about 3-5 hp. That's kind of a generalized statement because every engine is different. The trick with the U/D pulleys is that they change the actual diameter of the accessory pullies making it easier for the engine to turn them. So instead of say the alternator orginally robbing 5hp with the U/D pulley it might now only rob 2hp. Then you have a 3hp gain. Thats kind of general but you can get the idea.

Hey wildman, it says you're in VA. What part are you in?

 

[Shawn]

As I understand, an underdrive pulley for say an alternator is usually larger in diameter than the stock pulley. This would make it easiler to turn. So would an underdrive pully reduce the current being sent out by the alternator? I have a sound system and don't want to loose too much current from the alternator. Would this be a concern?

 

[twa]

Soundsystems generally negate any benefit of adding performance to a car because of the extra weight. If you're concerned about power output from the alt. you probably don't want to consider underdrive pulleys.....

 

[awdlax]

you could always buy a yellow top optima deep cell batery, or just a capasitor or two. Thats what i plan on doing. I get my pully fri. it really isnt hard, i replaced ooone on another before.

 

[blackp5ca]

From a past bad experience I would not recomend underdrive pulleys. Too much strain is put on the alternator and the battery plus the price:hp ratio isnt too good. (imo)
Used to have a set on my old 90 Mustang GT (apples and oranges I know)
after smoking two alternators and one battery I went back to the stock pulleys, never had a problem again.
I do have a UR crank pulley on my P5..been very pleased with that, no strain on battery (Auto-Meter volt gauge say not anyways) Car pulls harder in the higher rpm.
Just my 2 cents.