I just replaced the serpentine belt as it was fraying on my '05 R53 at 151,000 miles. While I was inspecting the pulleys I noticed that one of the previous owners had put an Alta 0% crankshaft pulley on there, and the old belt seemed slightly less wide than the new OEM belt that I ordered (maybe this was just from the general wear of the belt?). I had no idea at purchase that it even had that aftermarket pulley on there, even with a mechanics inspection only until I starting really looking at it. At some point I'd like to change out that Alta pulley and was wondering if I should just get a stock harmonic balancer or the ATI Super Damper instead.

ATI Damper

OEM Balancer

Any suggestions on replacing that crankshaft pulley, or should I just let it be?

 

Its widely suggested to stay away from the light weight units. They cause premature bearing wear. You can find pics of it online with a quick search.

A lot of people have had good results with the PRW fluid dampened units. They're a good option if your looking to save some coin.
https://www.waymotorworks.com/fluid-...ulley-r53.html

The ATI units are supposed to be awesome. Keep in mind the standard drive pulley is .8% bigger than stock.
https://www.waymotorworks.com/super-...ulley-r53.html

For the money, I'd go ATI over stock. Its lighter and slightly cheaper

 

I'm not sure how long that Alta pulley has been on there for... In terms of wear, do you know what specifically in the engine would end up worn down?

Also do you think I should get this replaced ASAP with an actual harmonic balancer?

 

I would definitely get it out of there. Here's a link to another thread with some good info on the topic
https://www.northamericanmotoring.co...nk-pulley.html

 

I have a ati on my w11 motor right now, i def can feel a difference in it, vs the stock one,(weight wise) it came with my motor so i can’t say much vs it compared to a stock w11 motor , but on a w10 and w11 is a major power difference and to be honest i have no idea who and when to rebuild

Def wasn’t new one i got it, came with the motor i bought
it

 

When mine failed I did my research and the ATI damper was the way to go for me. Good quality part from a big company that backs their product, and an upgrade over stock in every way. I put on the 2% oversize version because more power baby.

The Alta pulley only exists because the stock ones have a high failure rate and the ATI units aren't cheap. They fill a hole in the market for budget replacements, but I think it is an inferior option.

 

Not sure on the inspection and rebuild interval as the recommendation on their site was unclear, and I never contacted them to get a definite answer. It’s either 5 years for a 5.5” pulley up to 400hp, or 10 years for a street motor. The MINI pulleys are 5.67” or 5.75” for a 2%.

ATI rebuilds the pulleys for $75 if no other parts are necessary.

What % SC pulley with your 2% ATI, and what belt size are you using?

 

Factory JCW pulley. I'll have to check on the belt size.

 

the site is very very unclear on the rebuild times on these things yet idk even how to inspect it to even see if it’s still good or not, only thing i can say is my motor still runs? 🤷🏻‍♂️