What size belt are you guys running? I know belt slippage is something that they look for, but nobody has come out and said what size these guys are recommending... are you guys signing non-disclosure agreements or what? Ive got a 16% and running the JCW as was recommended by M7, but im not seeing an index hole so im switching belts to something shorter. thanks for your input and feel free to PM me if you think you might get in trouble for sharing secrets

edit: Not trying to start another "what size belt" thread where everybody posts what combination they are running. I know what works, trying to find out what works right.

 

I'm running 15/2 with stock belt.

 

What you are asking is to those that have had an in-person tune. I have the mail order LDG flash so I’m not qualified on that count.

From experience I can make these recommendations:
Standard pulley – OEM Conti belt
JCW 11% – JCW belt
15 % - NAPA 060539
19% - NAPA 060535, Gatorback 4060537 (mention, but not recommended)

The JCW (Gates) is supposed to be shorter than the NAPA 060539 but it’s not, it will slip on a 15% (or 16%). The Gatorback 4060537 is supposed to be shorter than the NAPA 060535 but it’s not, it makes up for less spring tension by having better belt wrap. I wonder how the printed lengths are derived; I’ve even seen different tension from one new belt to another for the same model Gatorback.

 

I had a new JCW belt on my car when I arrived at LDG.

15% pulley.

He noticed that it was slipping on the very first pull.

He installed the belt they recommend for the 15%.

060535 (not 060539).

The tune went fine afterwards.

After 3 auto-x events, and three track weekends, plus 7,500 miles, I can still see the one tensioner hole.

 

I have a custom sized gate's belt. I'll have to get the measurements, I don't remember off the top of my head.

 

The part number that Hornguys posted works with 15, 16 and 17% pulleys. This is true as long as the crank pulley is stock. The tensioner doesn't last forever so those with over 40K should look into a replacement if the car is going to be tracked regularly. Everyone who takes their mini to the track should have a spare belt and installation tool with them.

 

...to determine whether a belt tensioner is maybe about to go south? Is there a recommended chnge interval for the part? Or do you have to just wait for it to go belly-up?

Thanks.

 

Ours got real noisy before I changed it. Sounded like it was making a grinding noise. After I pulled it, you could see that it was messed up.

 

I'm on 16%, JCW belt and a new belt tensioner set. I can also see the index hole.

 

The tension comes from the caged spring and there is a small strut that is a shock absorber. This usually fails first by puking the rubber bushings at each end. Visual inspection is all that's necessary. Because of the high loads placed on the belt and tensioner by the supercharger, just replace it after about 40K.

 

Okay. Thanks.

 

So what size is recommended for the 19% pulleys? Since the belts mentioned up top are being recommended for the larger pulleys I'm assuming it might be smaller than mentioned...

 

I don't think they actually make LARGER pulleys. A 19% pulley is 4% smaller than a 15% pulley.

 

That would make the 15% pulley LARGER than the 19% pulley...

So, what is Jan recommending for the 19% pulley and stock crank?

 

Try again Nick, the OP you quote was stating the belts listed above are for larger then 19% pulleys.

BTW, the Alta twincharge kit comes with a larger then OEM sized pulley, so yes they are made.

 

Ahh, I read it wrong, I saw larger pulleys and got confused .

I still have to check what the length is on mine. IIRC we tried to get a super tight belt stretched on but couldn't get the smaller one on.

I know the twincharge kits are bigger (To underdrive the SC), I was just talking about the standard offerings (Stock, JCW, 15, 16, 17, 19)

 

Right, I read your post wrong.

Probably check with Danny on the belt sizes, he stocks several sizes and probably has a bit more familiarity with them.

 

I figured you read it wrong, considering the lack of punctuation and all lol

Going to do a little tune-up for the new year so I guess I'll just contact Jan directly and see what he says.