What is the difference between the two? I don't know which one I should get. I would like more power and better sound, but don't wanna have a lot of problems down the road. Which one do you prefer?

06' R53 Stick
Everything is stock except the air intake

 

Both are safe, a little more low end with the 17%. Do what I did 15% with a +2% crank pulley. Gonna have to replace it someday anyway.

Nik

 

i was going to have a 15% installed, but Pete over at Greasys Garage http://www.greasysgarage.com/main/ (a good shop in MA to have MINI's modded!!)convinced me to do the 17%!
I have been happy...so much I kept modding my MINI!!

 

2%?

Sorry, I couldn't resist.

The 17% will give you more power, but it will also give you more heat to deal with. If you track the car, a 15% is a better choice as the car can recover quicker. However, for street, the 17% is much more fun!

 

Zippynh how many miles are on your mini?

 

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That pretty much sums it up.

The 17% is more prone to squealing but not everyone has that issue.

 

I just put a 17% on mine just this past Saturday I love it

 

LOL
For the first 5 years it was a garage queen/toy.
now it has transitioned to a commuter, driving it about 2 hrs a day roundtrip!
As of now, barely 65,000 I seriously need to find more time to have fun in my MINI!! But looks like I'll be going to MOT (Mini's On Top), a together where several Hundred MINI's drive up mount Washington...
http://minisontop.com/

But a few other folks here that I have meet up with at greasy's have LOTS more! He is honest in saying that most of the 15% he installed, were later removed....changed to 17%!!
In the NE, where we DO have 92-93 octane, the 17% reduction is a great size...the reduction size works well for NE driving....lots of decent pick-up down lower/midrange, so good for a daily driver/commuter.
When I was looking to have it done,I found WIDELY ranging prices to have the pulley installed....that is how I found Greasy's. He did the install in MAYBE 30 minutes, stocked them, and since then, anything that comes up, that I do not want to DIY, Bushings, Struts, etc, I get it done there! Good set-up. They know MINI's VERY well!

 

I had a 15 and went o 17. No regrets and currently at 96000 miles.

 

As far as the difference between the two when it comes to milage on your motor or wear on the S/C, there really is none, they would both give you the same longevity & wear, and both have proven to really change nothing in these areas over stock in the real world.

The only real difference is what DaFlake pointed out, heat transfered into the motor:
(Again just use this as a rule of thumb)
15%
Street - OK
Track - OK
17%
Street - OK
Track - Better I/C

And while 17% will prob. be more fun on the street, IMO if you decide to go that route, do just that, 17% not the 15%/2% combo, while it usually works out just fine, I feel that unless you've already installed a 15% and want a little more w/o doing another pulley swap, your better off just starting with a 17% on the S/C only and not spinning "all" of your other accessories faster for no real reason.

 

I will also be doing the 17% pulley soon. Hoping to add to the grin on my face when I drive the Mini.

 

I'd add....
the 17% on the track/Auto-x is more likely to shred belts, but the often forgotten item is if you have PROLONGED high RPM running, you can have some cavation of the coolant around the water-pump..... not a concern for street driving. Simply put, If you run the water-pump at 17% above its design speeds for longer periods of time, tiny bubbles can for form around the water-pump vanes....reducing the pumping....A spike in oil temps is usually the first thing noticed, since the stock oil cooler uses a coolant loop to help modulate/cool oil temps.
For me, I drive on the street, SO the 17% was the BEST way to go.
Going with a 15% and a -2% (get you about a 17%) from the start has drawbacks....as mentioned above (over spinning the alternator+A/C compressor),with higher upfront cost.
One thing not mentioned here is 19% reduction....once tried by many, but very few stuck with it. It was just a bit too far....and more work...thing like Tunes, fuel injectors REALLY NEED to be done to do it long term, but many cars have had 17% for MANY MANY miles, no issues related to the pulley!

Overall, you get a STRONG go it!! Just make sure the car is running good FIRST...no pings or knocks, no codes.

 

I wouldn't go with a -2% crank pulley either, it's not worth the potential headaches, just go 17% and be done with it if that's the reduction you want.

I wouldn't run a 17% on the track though, even with a larger intercooler. It's still creating too much heat, especially for those who live at 7000 RPM plus,if you've moved your redline up. Maybe with water/meth, but it's not doing anything more than a 15% would at those RPM's, except spinning faster with more potential wear/tear on the belts and more heat. GP intercooler helps, but it's not magic.

 

I wouldn't (and don't) worry about the AC or the alternator spinning faster. The AC only stays on at certain rpms, at wot the clutch disengages, and the alternator charges based on battery needs. Bearings may fail sooner, can't say that I've heard of that happening.

Nik

 

To each his own, but my car spends most of it's time on the track. I agree 100% with what was previously stated--15 or 17% for the street, where you're never going to see high RPMs, 15% for the track, but then again we're trying to get IAT's/oil temps/water temps as low as possible. Most of the people who are on the track run either the JCW pulley or 15%. In fact I'm not sure I've ever met anyone who tracks frequently with 17%, but that doesn't mean someone isn't doing it. But the heat it generates will be more harmful than any low end torque gained, especially since we're not running at low RPMs. The street is a different story.

 

16%??? WMW and M7 sell a 16% and its what I plan on doing as my car makes frequent trips to redline and stays at 4k-6k for long periods of time.

Maybe someone who knows more may be able to enlighten me to why I shouldn't do 16% but for now it seems like the good idea for me

 

I talked to way when I ordered my 17% because I was curious about the heat he told me yes it does get hotter but not enough to cause any problems the main difference is that it is more aggressive bottom end that the 15% but with the 17% you are not making as much power tip end as the 15% so just depends on your driving like said above high rpm's long periods of time you probably want the 15%

 

Hmmm....I guess that's both right and wrong. The 17% maxes the supercharger out at lower RPMs than the 15%; above the point where the supercharger isn't making any more power, but is spinning faster, it's generating more heat, which kills power as the temps go up. So it's capable of making just as much power as a 15% at the top for a period of time, in fact it gets there quicker (or maybe saying at lower RPMs is more accurate), it just can't maintain it. A larger IC helps, but it isn't enough in and of itself.

On the track, there is no such thing as heat not making problems...We have enough trouble keeping oil temps reasonable with 15% pulleys. Again, the GP IC helps, but it looks like water/meth or pure meth is the answer.

 

I don't track my car so he told me the 17% would be fine I'm not running it hard every time I drive it neither it seems that if your running yours on the track it's a little bit of a challenge to keep it cool

 

I hope you guys are factoring in bigger injectors, and at least a software upgrade when decreasing the pulley size.

 

I plan on getting the 380 injectors can I run those on my mini s or do I need the jcw map on it?

 

Nope....90% of -15% and maybe 80% of 17% (just a guess)are running stock injectors, no issues....the injectors become worth it when doing a tune, cause you can get more out if the motor with a pulley/injector/tune combo.

 

I am running a 17% with stick injectors now no problems but I plan on getting a tune and was going to get some but sounds like I better wait until I go get it tuned?

 

As long as you don't go larger than 380's you can get them & install them whenever you like, the ECU will self-adapt to them well enough, then when you het your tune you can take full advantage of them.