I am looking at getting a pulley kit, or lightweight crank pulley for my 2.5RS. I have looked at Perrin's lightweight pulley, and GFBs pulley set. Also, flat4engineering.com has a set, but not sure. Does anybody have any suggestions?
I want a kit that gives more response from my engine, without making it so the accessories (radio, headlights,etc.) suffer poor effects at idle speed. Thanks!

I know Vishnu's is undersized, and will cause things to dim at idle. Perrin's is the normal size and works just fine. That's all I've got.

Unorthodox makes a great set for this application.

i have the grb pulleys in stock for 260. including the belt. gfb is all we use at flatirons imports. so if they pass the rigorous r&d of the dealership i would have to say they are the best fit and bet for ya.

aaron uhl
303-442-1769
flatirons imports

I had an Unorthodox pulley on a 2000 2.5 RS and it worked very well.Noticeable upgrade.

I was thinking of going with a lighter pulley too, but not underdriven. I've heard most of the power gained is from mass reduction anyway and since the belts on underdrives are not standard sizes they'd be a little harder to get when it comes time to replace them.

Perrin lightweight pully is good because it's the same size as stock, so you don't have to change all of your belt.

Also, no one has said anything about damping... as far as I know, none of the pully's mentioned have sound dampners. Over time wont the pully's destroy your engine?

Yes. Damping is important, and I know that the unorthdox had an optional damper for the pulley on my old Eclipse, not sure about the Sube, but I'm sure you could find out easily.

I didn't think that pulleys would destroy the engine, since a lightweight pulley simply makes your car run more efficiently. What exactly is necessary, regarding the sound dampening? Can someone please explain me this concept-I've never heard of it
Thanks again

Subarus are internally balanced so the dampening is strictly for the more smooth feeling while running and comfortable idle. The GFB pulley set for your RS maximizes the weight savings by replacing the Crank, Alternator, and Power Steering pulleys. The main crank pulley is undersized; however, the alternator pulley is proportionally undersized thus, the rotational speed stays the same and no loss in alt output at idle. The belts are available from larger parts stores and worst case scenerio you have to order them with a day turn around. I would have a set of belts available anyway whether your car has aftermarket pulleys or is completely stock for the "just in case" circumstances.
The only downside to any LW pulley is a possible CEL caused by the engine revving and decellerating faster than the ECU sees as normal and turns on the light. Other than that I haven't seen any other issues.
Just my .02 worth

Troy

T-WRX450: You said that "Subarus are internally balanced so the dampening is strictly for the more smooth feeling while running and comfortable idle. " So your saying that a lightned assesory pully without a sound dampner is ok?

I thought that if you change the weight of the assesory pully you unbalance the engine. I know that the engine's come balanced from the factory, but without a sound dampner in the pully, does it not vibrate the engine apart?

nitro,
You are correct you don't need a dampener on the pulley. The lightweight pulley will not harm the engine even in the long term.

Troy

T-WRX450- Then why does Subaru put dampners on pully's from the factory if there not needed? Doesn't it cost more to put something on that is not needed?

nitro,

The factory puts a heavier "dampened" pulley on to give the engine a smooth feeling idle because even though it is internally balanced, it still will have a little vibration. Just as the factory has a flywheel that weighs ~25 lbs, they use the momentum of a heavier component to smooth out operation. If you change the crank pulley without changing the flywheel then you will probably not even notice any change in vibration. The factory builds the car for regular people to be comfortable. We modify the car to have more performance and a pulley will provide better response.

Troy

Right on guys,
Just got my perrin pulley installed today, and it does accelerate smoother and a bit quicker now-its even more noticeable with the A/C on, the car doesn't feel bogged down by it. This is definitely a mod I recommend. No CEL either! :)

Troy,
Even though you might not notice a difference in idle and smoothness of revs, pulleys are dampened for a reason. Not just for regular people looking for a smooth ride. Over the course of a car's 100,000+(hopefully) lifetime, it puts more vibrational wear and tear on rotating parts, particularly the crank. Here's a good article on it:

http://www.dinanbmw.com/html/danger_of_power_pulleys.htm

I'm not saying don't get one, but it's something to be aware of for the tuner looking for great reliability from their car.

7

Wow, great article impreza7. Where did you find that?

I've got mad hooks in the DSM world, one of my buddies forwarded it to me.

You guys need to do more research and get your facts straight. Distinguish between a lightweight pulley v. an underdrive and lightweight pulley, learn whether Subaru's pulley has a harmonic balancer as part of the pulley, find out whether this mod alone would void your warranty.

I have yet to come across anything that is supported by verifiable evidence that a lightweight pulley will cause damage to an engine. The only downside that I have learned is that the car may feel slightly less smooth when idling but that most drivers would not notice it. The upside is increased acceleration since their is less rotational mass that the engine must spin when turning over. This improvement is particularly pronounced when leaving from a stop. I have heard one person analogizing the performance gain someone might notice if they removed 65lbs of weight from the car. If this is true, which I am not alleging, then it can only be true for acceleration purposes and not true for handling purposes.