Hi there, although I haven't had my car for long, and I am extremely impressed with its performance, wondering about modifications already. Reading here I found that people install all sizes of reduced pulleys. My question is, what would the approx HP gains be for the more popular sizes? IE 15, 17, 19 percent? I want to keep the car as a normal daily driver, not a race car, and of course thinking about longevity would like to not "hurt" the car with any mods I do to it. My thoughts are if the 15% gives a decent gain HP-wise and doesn't affect the car too much I may go with that. Thanks for any thought or advise to a new mini owner with a massive perma-grin.....

 

15% is my choice for durability but you should already have a reduction pulley with the JCW, something close to 12% I believe. For a few percentage points, I don't think the gain will be worth it. Do a search on the forum and I think you'll find similar opinions.

 

Imo on a jcw, go stright to the 17%..as long as it fits your driving style..(non track, lower rpm streer....
the 15% will not be very noticable....

 

17% -- is my choice
I raced a R56 JCW yesterday, no chance! I buried him alive.

 

Until he pulls out his boost controller... then with a hit of a button...

 

then you activate your N2O and watch him disappear in the rear view mirror

 

17% is quite an increase, but you can "re-learn" how to drive the car. The JCW pulleys are already reduced more than a stock MCS. %15 is "safe" as another put it, you may run into "issues" using a %17, I am anyway...

add more boost, and other stuff "starts to go", so possibly be prepared to replace other bits: IC boots, SC intake tube, ect.

 

How many miles are on your mini? if you are getting into the 60-75k range and you may have to do your crank pulley soon take that into consideration. If you go with an ATI Super Damper (highly recommended) it is about .8% larger then stock.

In my conversations with Waylen from Way motor works, I was going to order a 17% as my car is just a DD no track time and he advised that with the regular ATI Super Damper to go ahead and get a 16% pulley to keep the boost at or around 17psi. So I now run the ATI Super Damper Crank pulley and WMW 16% Supercharger pulley and the combination is awesome!

 

I have a JCW pulley (12%) so I went with a 2% ATI Crank Pulley because my car had 75,000 miles and I was a little worried but the stock crank pulley eventually coming apart. The combination is about equal to a 14% S/C pulley in terms of S/C RPM. I gained about 1 psi boost with the 2% crank pulley over the JCW max boost.
I am happy with the upgrade.

Also, most of the S/C pulley removal tools do not work well at removing the smaller JCW pulley so if you decide to swap the JCW pulley to a 15% or other pulley make sure you can rent/borrow a pulley removal tool for the JCW pulley.

 

It's not worth changing.

Numerous JCW's with the stock pulley making big power ~250-260whp (with head/cam/header).

 

+1

I'm on the stock pulley. IMHO, the JCW pulley is fine. Spend your money on cam and header and tune and you will be very happy!