Is the stock Evo Crank Pulley used as a harmonic damper/balancer?
Anyone using the Evo Perrin Lightened Crank Pulley? Is it worth it? I have not heard anything about it in the forums.

Are there any balance or harmonic issues with it? Below the link for it.

http://www.vividracing.com/catalog/p...07-p-4844.html

http://www.boneheadperformance.com/M..._Code=EVO8-76F

Looks like Perrin removed it from their website. Not sure why.

Only two crank pulley I'd consider are stock and Fluidamper

The Fluid Damper Crank Pulley is 6 pounds. I think it is even heavier than stock. So no advantage in using that.

You need harmonic damper in the Crank Pulley. The advantage is has a better harmonic damper then stock.

Yes, the stock crankshaft pully is a damper- the advantage is that it reduces vibrations that can potentially damage your engine.

as for harmonic issues with the perrin unit (or any other crank pully that doesnt have a damper in it), removing all that mass from one side of the rotating assembly could very likely cause damage. Alot of people do this mod to gain engine "response" or "free up power", but it can be potentially damaging.

Is it really a harmonic damper? On the Subarus WRX and STI it is just a pulley. No damping on it. It has even been verified by Subaru.

Subarus use a Boxer engine design with a much shorter crankshaft. I personally wouldn't run one on the 4G63, but there are plenty of people who do that haven't seen an issue.

The factory pulley is indeed a harmonic damper. If the Subaru doesn't actually have a damper, it may have something to do with the fact that it has a short, flat crank.

The real-world value of a damper has already been demonstrated in this forum some time ago in the form of main bearing longevity. There is no good reason not to use one.

Sorry to bring back a dead thread but I have been doing some research on this..
First off in all the threads I dont see a mention of what seems to be obvious, simple design.
If you look at the stock damper it doesnt actually have any sort of dampening material on the actual pulley... it does have the rubber on the outside but I hardly see how that would actually reduce vibrations of the crank.. I can however see how it would reduce noise and cross vibrations i.e. reducing vibrations from accessories being sent back to the crank.

My thought-
You should be ok to run an aluminum pulley on a 2.0 with basic bolt-ons. Not saying this wont reduce longevity but I dont see it being tremedously horrible.

On a built 2.0 or stock 2.0 with more then bolt-ons/cams I would run the stock damper unless your pushing a lot of power.

With a very high HP output or a 2.3 or other motor with longer stroke I would run a fluidampr or other pulley with actuall dampening properties.

Just my thoughts.

FYI I have been running a aluminum damper on stock 2.0 with cams/bolt-ons 360+AWHP no problems, of course each car is different as we all know

Does anyone have experience with the ATI damper on the EVO?

This has been explained to death in prior threads. Harmonic dampners are essential for your engine life. That's why the factory put them on the cars. Fluidampner and ATI are better than stock, and cannot come apart with rubber fatigue, like the OEMs do, which is why they are better. Buy one and use it.

The ATI dampner is very well made. The disadvantage for the ATI is that installation is much more difficult than the Fluidampner because of the way it's mounted. There are a number of threads discussing this issue when they first became available. Mike from AWD is one of the people who had experience with this. Search and you'll find it.

Thanks. We got a GB on them for the E46 and I'm waiting on mine. I know the installation is a pain, but according to ATI, the interference fit is part of what make is such a great damper. I would think it'd be worth the trouble. If/when I get my EVO, I'd definitely have it as one of my first investments.

I'll search around. Thanks for the response.

Previous owner of my evo had a Perrin lightweight crank pulley. Some advantages it 'felt' like it revved up easier, a little easier to rev match as well. Idle was choppier though. I quickly removed it and installed an oem crank pulley given to me by a local evo owner. A few issues that 'might' happen with these aftermarket lightweight un dampened units is causing false knock. Idk if I had any of that but after putting in the oem crank pulley car felt much better. I didnt even want to bother selling that perrin crank pulley to some unknowing evo owner who would think it would be good for his car so I just chucked it in the trash.