1st Gen R53 Cooper S Most liked posts in thread: 15% vs. 17% SC Pulley

I would stick to the 15%. The 17% is going to overdrive the S/C at medium to high RPM and you already have 100K on that S/C, why ask for trouble.

Before installing I'd do a compression test. At 100k the engine might be getting a bit tired. It's cheap insurance that there is nothing terribly wrong with it now before stressing it a bit more.

 

A 15% is all you really need on a motor that old / young. 15% is good and reliable size.

You can also make lots of power with just a 15% ...see below.:ihih::ihih:

 

Nate is right on there!! YES you WILL see a better low to mid range over the 15% with the 17% pulley, but if you put two cars together , one with 15.. and the other 17% it will be the difference in the drivers, not the pulley, that that is in front. And the 17% will generate more Heat, causing the ECU to remove ign timing and fatten up the fuel when the knock sensor goes nutz!!

Testing of pulleys has show the 17% will allow more power than the 15%, but the ecu will usually KILL that increase when detonation is increased. Some have gone all the way back to a 11% to kill the add'l heat and actually keep the power.

Just saying...........................

Thumper

PS: look into a water meth system to make it all happy!!

 

FWIW - I agree with all of the above for cars with a manual transmission.

On cars with the automatic, the 17% is a better choice, as the auto limits the car to lower revs (6700 and below) and the 17% will yield more low-rev torque which helps the auto considerably. I've run both and wish I had started with the 17%.

I assume you have a manual, but just covering all the bases here.

 

Or you could reverse engineer think about it. My 03, original supercharger with 100,000 miles on the 17% pulley I bought from Helix years ago. It still runs like a scalded cat @ 130,000 miles.

 

Alta = "it almost fits"

 

Imo, choose the pulley sized based up how you will drive, and the most common octane in your area....
in the northeastern us, we have 93/94 at the pump ...so the 17 is fine for a non redline driver ....
In other areas, not having 93/94 might mean the extra temp of the pulley might result less power at times....so a 15% or even jcw equivlent might be better...again depening on how you drive, and where...no hard and fast rules, but more info on you planned use beyond miles would be useful.
the total miles...not so important...you either have good compression, or you don't...
Hech the sc could be worn out...know your boost?! It is a bit of a wear item..... but folks run it till it fails...usually the waterpump gears.....

 

+1.......

 

I'll bet our headquarters are closer, or the same distance. Just sayin...

 

Hi Paul
How's it going? I agree with you on the pulley on the automatic.

 

I have a 17% put with a rebuilt s/c installed about 3,000 miles ago.

 

I agree with Kellen. I've installed almost 500 pulleys and would love for you to buy our WMW pulley, but if your looking for someone close. I would go with the Craven pulley over the Alta.

 

Stop by any time.

-=Kellen