Hey everyone,
I'm preparring to have a 15% pulley installed on my S, does anyone know if the JCW belt P/N 11-28-7-545-120 6PK x 1374 will fit or should I use the aftermarket belts recommended to go with the smaller pullies? Thanks for the help!

 

I bought the one that Alta recommand with the 15% pulley (NAPA 060539)
and got a squealing noise. I've been told by a friend to buy the JCW belt.

 

Belt squeal comes from a miss-aligned pulleys, or contaminated belts (by oil or grease)......not a belt that is too long or too short (if it is slipping, it can make a bit of squeal, but most folks see power loss) I guess, but....the Goodyear Gatorback sometimes helps people with a mild squeal....unlike a traditional 6 rib, it has 6 ribs that start and stop....some have had problems....but if it fixes yours... There has been a bit of debate on the Alta recommended belts.....ask what people use, and the answers vary a bit.The problem with belts is the they vary in size, brand new....some 539's are some time shorter that 535's....makes no sense, but true...some love NAPA, some gates, some CarQuest...all made by Gates...but they vary...go figure. Also complicating the issue, is that the euro belt sizing system is different than the US system...

One tip....non-oem belts need to be change more often than OEM....and pulleys are tough on belts since there is less surface area for them to grip...so the smaller the pulley, the shorter the life of the belt...The SC consumes a huge amount of HP...so the belt does a lot of work too...many folks keep a spare belt in their cars just to be safe, and save a tow!!

 

I'm a big fan of the Napa 060535 belt on a 15% pullied car. And changing it yearly. Cheap insurance.

 

Also, tensioner stop. Cheap insurance that saves you a lot of headaches if the belt come completely off or snaps.

 

YES
and YES

 

Thirded, I run the same combo.

The Alta sheet is wrong, old outdated information.