Which pulley will produce more power the full Greddy set ( 2 pieces)? or the Unorthodox pulley set? I currently have the Greddy pulleys but is thinking about upgrading them to the Unorthodox pulleys. Is it worth upgrading? Thanks

 

its not worth upgrading.

 

I would assume the difference is purely aesthetical.

 

Greddy does not offer pullies which release power. GReddy pullies are for the air pump removal ONLY.

Be careful with an Unorthodox main pulley install:
http://www.mazdatrix.com/faq/pulley.htm

 

^why is it not worth it?

 

The gains aren't all that much. Also, underdriving your accessories makes them not work as well (i.e. underdriving your alternator can cause problems if you have a large stereo, underdriving the A/C makes it less effective, etc).

So it all depends on what you are doing with your car whether underdrive pullies are worth it or not.

 

SR claims there complete pulley set gains 14HP but i dont know if its verified.

 

www.srmotorsports.com

 

The GReddy pulleys do underdrive the alternator and water pump, right? That would result in less parasitic drag, giving a slight power increase at the wheels.

That page on the Mazdatrix site is based on my engine after I botched my UR main pulley install. There is nothing wrong with the UR main pulley (it is actually a very nice part), but you do have to be careful when installing it. Other underdrive main pulleys don't require the removal of the stock pulley hub. The install is much easier when you don't have to remove the hub.

I am currently using the stock main pulley with SR water pump and alternator pulleys, with the intent of maximizing belt contact on the water pump.

-Max

 

I run the Greddy alternator and water pump pulleys with Unorthodox main and power steering pulleys. The only reason that you would think about switching from the Greddy to the UR is to have "matching" colored pulleys. I just polished the annodized blue off of the Greddys to match the polished silver URs.

 

Isn't the Unorthodox main pulley lighter weight than the Greddy with the stock hub? Unorthodox claime the bulk of the hp gains are from reduced rotational mass.

 

Guys, the Greddy pullies do not replace the main pulley. Any real gains are going to come from the main pulley replacement. Jason of the RX-7Store.net saw a 15rwhp gain on a dyno however from a high HP car (400+). Gains at the lower HPs would most likely be less.

Max is correct, the Greddy pullies are larger to a degree. However, it's not really for the sake of performance. The goal is to enlarge them enough to give a better contact with the water pump when removing the air pump.

 

GReddy does not make a main pulley replacement. But the UR main is lighter than the other aftermarket main pulleys that use the stock hub (when you include the weight of the hub, which is required with those pulleys).

The quote from UR about reduced weight being the main power advantage may be true for cars in general, but I don't think it is true for the FD. The stock FD pulleys aren't very heavy, and the aftermarket ones aren't much lighter (the stock plastic PS pulley is *lighter* than aftermarket replacement, for example).

Here's my SWAG on why the weight of the pulleys is not the most significant aspect in freeing up power using pulleys on the FD, and why underdriving the accessories probably is:
1. the alternator seems to have a larger moment of inertia than any of the stock FD pulleys
2. the alternator spins faster than the engine
3. based on 1 and 2, it seems likely that reducing the speed of the alternator is going to reduce power losses more than reducing the weight of the pulleys

And before anyone gets confused, as always happens in underdrive pulley discussions... there are two ways to reduce the speed of the accessories (to "underdrive" them):
1. make the engine pulley smaller
2. make the accessory pulley larger
Underdrive main pulleys are smaller than stock. Underdrive accessory pulleys are larger than stock.

-Max

 

Max: In the case of the Unorthodox pullies, the Main is smaller and the Alt is larger. I don't know what the net effect on the alternator spin is, having not done the math. I thought I had read Unorthodox intent was to leave the Alternator spin unchanged.

 

Wait a second..I got that wrong, the Alt is definitely underdriven.

 

After reading through this post I just have a quick question. Is there any usefull difference in going from stock pullys to greddy if my car is slightly modded (still stock twins) and has a system (sub, amp, the works)? Thanks in advance.

 

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