Pulley Question

[spoolintsi97]

Do the unorthadox pulleys run off of the same belts as the factory pulleys or do you have to change the belts because i wanted to buy them one at a time and put them on because my power steering pulley is bent

 

[ericmetcalf11]

No, they are different belt sizes.

That is why it is called a *underdrive pully*, because it is smaller. So you will have to change your belts.

-Eric

no sig

 

[95blackGsTurbo]

Don't post information unless you are sure you know what you are talking about. I have one on my 1g and had one on my 2g as well and it is the same size. They have to be. They are just lightwieght. Made out of CNC aluminum and lightened by drilling holes in them. Mine uses the same belt as factory.

 

[spoolintsi97]

are you sure there the same because i am going to buy the one and i dont want to be stuck with the pulley sitting aroound until i get the rest of the set

 

[95blackGsTurbo]

Even IF it isn't the same, which it should be, all you would have to do it get a belt that is an inch shorter or so. They are labeled on the back of the package how long they are. We get that all the time here. People looking for belts that are 1/2 or an inch shorter. No big deal you can still use it.

 

[ddavisaf]

They're lighter, therefore take less efford to "drive" the pully. Thus "underdrive".
Same size though.

 

[gsx951]

Search this and find out why the under drive pulley is a bad idea.

 

[spoolintsi97]

Ok im just going to get it if i need a belt i need a belt thanks for the help

 

[spoolintsi97]

One more thing is it possible for a pulley to warp i put a dial indicator on it and it is moving the needle at a certain point i didnt no it was possible for a pulley to bend

 

[oldman]

All of you are right and wrong at the same time. There are two types of aftermarket pulleys.

1. A lighten crank pulley, what 95bLaCkGsTuRbO was talking about, which is only lighten and still uses stock belt size.

2. A lighten underdrive crank pulley, what ericmetcalf11 was talking about, the word underdrive does not refer to underdriving the crank pulley due to the reduced weight, rather underdriving the accessories (water pump, ps pump and alternator) by reducing the diameter of the crank pulley therefore will require shorter belts.

Here's a quote right from Unorthodox site:

The second type are our crank pulleys which are available in three (3) versions. First is the underdrive crank pulleys in standard belt layout (Ultra or Tuner S). They drive all the accessories that were available in the car from the factory. This version is up to 20% smaller in diameter ("underdrive," see the next FAQ question). But more important is they are 60-90% lighter than the OEM pulleys they replace. It's another reason why we do all of the underdriving at the crankshaft pulley to maximize the reduction in weight on the crank. Second are the stock diameter crank pulley, also in standard belt layout (Ultra Sc). It is designed to maintain alternator output at stock output levels for car owners with big stereos (over 600 watts) or for audio competitions where system voltage must maintain specified levels (see your sanctioning body's rules). For cars with superchargers kits it maintains the original level of boost from the aftermarket supercharger kit. Third are the single belt conversions (Ultra R). This version was designed to drive only the alternator or alternator and water pump (depending on the application). It is used for engine swaps or for the racer where only the alternator is being used. This version has the same percentage of underdriving as the Ultra or Tuner S versions but is 90-95% lighter than the OEM pulley it replaces.

So the answer to spoolintsi97's original question is "depends on which you got?". I suspect you have the underdrive one which will require new belts. With all that said, the best answer to your question is this post by gsx951.

Search this and find out why the under drive pulley is a bad idea.

 

[oldman]

Also from the same site:

2) "What is underdriving/underdrive?"
Underdriving/underdrive is slowing the speed of the accessories, or the driven component, from their original factory speed. Underdriving can be done in two ways. First is by increasing the diameter of the accessory pulley/s. The problem with this method is it increases the size of the accessory pulley/s which increases their weight. Weight reduction is the most important key to increasing engine performance and response. This method also eliminates the ability to underdrive the a/c, which is a tremendous robber of horsepower. The second, which we use, is reducing the diameter of the crank pulley. This allows us to achieve the best ratio of underdriving, and most importantly maximizes the reduction of weight on the crankshaft. This reduction in weight reduces the moment of inertia allowing your engine to respond faster to throttle inputs and perform better at all RPM's. This method also allows underdriving of the a/c we can maximize the performance of our kits by not leaving any accessories to rob precious horsepower from your engine.

 

[95blackGsTurbo]

Why ya gotta break balls?? Good point though. I never knew that.

 

[oldman]

Why ya gotta break balls??

Sorry just part of our job description, break balls.