Reduced Supercharger Belt?

[MAFFA]

Simple question i'm sure but not being familiar with the belt set-up of my R53 Cooper S just yet I thought i'd ask.

If reducing the size of the supercharger pulley with a 15% it is recommended to get a reduced size belt. If at the same time you add a 2% increased crank pulley should you still use a reduced belt or would that then make the stock one okay?

My guess is that the increase in the size of the crank pulley wouldn't really counteract the reduced size of the supercharger pulley & so a reduced belt would still be required?

Cheers

MAFFA

[Lucky Dave]

I would normaly fit a smaller belt, dont use your old belt as a measure as it will of streched!

Once new belt is fitted you need to look at the tensioner stop to unsure it has enough movement left, a belt too long will break the tensioner stop off.

[MAFFA]

Cool cheers. I'll not be doing it myself so i'll get a smaller belt first.

Thanks

MAFFA

[DaFlake]

There have been a few posts on this between MINI2 and NAM. I believe that someone showed that you should try to "split" the lock hole for the tensioner. This hole is visable if you shine a light down towards the pulley. The little hole is used by sticking somthing like a small allen key in it to keep the tensioner loose. With a 15% pulley many folks have run stock. I did this for a while but soon realized that my belt was actually slipping so I moved to a smaller belt and found the new power. I highly recommend a smaller belt as well. If you are doing it yourself try to borrow a tensioner tool as it can be a pain to get the tension off of the belt without it.

[MAFFA]

I'll more than likely give these guys a call:

MINI Motorsport Centre

They're only down the road

MAFFA