Any thoughts, they both achieve the same results as far as I can see. Anything I'm missing? And anyone feel strongly about either choice?

 

I had my 15% and 2% pullies installed seperately, about a year apart. If I were to do it over again, I would just buy a 17% pulley and be done. I can't tell any difference having a lightened crank pulley at idle, and as far as I see it, its just another $150 bucks spent on a part and $150 more in labor. I definitely recommend going with a 17% or 19% pulley reduction compared to 15%. The top end is basically the same, but the car's powerband starts in about in the low 3000 rpms now compared to almost 4k with the 15% and 5000+ with the stock pulley.

 

Save your money and just get a 17% that way later down the road if you decide that you want a little more you can always get the 0% or the 2% crank and still be safe. -- Johan

 

Most likly the power will not be enough with a 17%....so you'll eventually probably want a 2% crank....so what I would recommend is getting a 17 or 19% pulley and leave it there for a while, then if you want more power still, add a crank.

-Cody

 

Here's the best piece of advice:

No matter what you choose to do, it will NEVER BE ENOUGH POWER!

Many, if not most of us MCS owners on NAM have done mods to our cars to extract more power. What nobody tells you is that it is an addiction. One mod opens the door to the next mod, and so on, and so on. Pretty soon, you've spent thousands of dollars on your MINI, and then you hit the wall. The wall where mods start costing much more, for less gain. I'm talking about your new cylinder head, cam,, throttle body, etc. Or do you bite the bullet and go with a twincharge kit, which you probably should've just done from beginning, but you've already bought the reduced pulley. So now what?

I just want to warn you... Your car will NEVER be "done"...

But the journey is fun, and addicting, and expensive...

Good luck. Think long term! If you really want big power, over say 225 bhp let's just say for argument's sake, maybe save your money for a twincharge kit from Helix, Webb Motorsports, or Alta. In the long run, you'll spend less, and get more.

Or, wait to see what happens with the Eaton M62 supercharger that's being developed right now for our cars. (Our cars currently have an Eaton M45, a smaller supercharger). Search for "M62" in the Performance Mods: Drivetrain threads, and you'll see many articles.

 

I love my 17. I went up against a same year model (06 MCS) that had a 15+2. I accelerated a tad quicker and maintained throughout the curve. Not only that but you retain the vibration damping feature built into the OEM crank pulley. If you have an 05 or 06 then the crank pulley is a little lighter than older cranks. I also saved a few bucks by not going with the reduced crank pulley. Just my .02

 

It's an oversized crank pulley, not reduction. From another thread on NAM and webbmotorsports.com the 05+ Vibration Damper is almost 2lbs lighter than the pre-05 Damper's. I have one going on my car today because my '02 Damper was suicidal and shredded itself apart. :impatient BTW, I went with the 19% pulley and am not looking back. I'm in Florida and I haven't had any problems with it, except that I can't track the car.

 

15% put's less stress on the belt than 17-19% due to it's larger diameter. Adding the larger crank pulley gets you lower rotating mass and greater pulley reduction without the stress...best of both world

 

If you assume that the supercharger will spin at the same rpm's with both choices, in theory the 15% + 2% lightweight should have better performance since you are also reducing rotational mass. You will, however, loose the dampening and there are very differing opinions on that. (take your pick)

Anyhow, I have read in some other threads on NAM (which I couldn't find right now) that the 17% and the 15% + 2% do NOT make the supercharger spin at the same rpm's. I'll try and find the thread and post a link to it.

Edit: Check out post 16 on this thread https://www.northamericanmotoring.co...ad.php?t=73952. Assuming that info is correct, the 17% pulley with no oversized crank pulley will spin the s/c faster than the 15% + 2%. No info, however, on the lightweight effect of crank pulley.

 

It was close...something like 16.8% for 15+2...

 

Just do the 15% and 4%. Lots of track time and lots of fun. No belt problems

Ah . . . but the M62 is coming soon! Forget what I said.

 

Yes...I will have a 2% crank pulley and a 15% SC pulley for sale soon

 

I'm crying in my coffee (well, it's tea really....).

Matt

 

Ok, so I miss spoke. I meant the crank size gets increased.

All in all it's all good and some things are just a matter of preference.

I prefer the 17. Why? Cuz it works jest fine fer me.

I too will have a 17 pulley available soon. Plus an 06 supercharger, OEM IC, S sport susp. springs, RSB, struts, S-lite wheels & Goodyear runflats, S brake calipers & lines, black body trim, exhaust and probably some other small odds and ends. Keep an eye out in the market place for this explosion of parts. Mileage 16k. The pulley has just over 10k.

Matt - Here's a tissue fer yer issue. 1+1 is suppose to equal 3 today, 2 tomorrow and probably 4 next week sometime. Jest a$$ my boss. She's a freakin' genius.

 

I live in florida too, and have been trying to talk myslef into a 17% but if your not having any problems with a 19..... I'm not going to track my car either, but i thought that you needed bigger injectors and a remap if you wanted a 19%

 

you dont "have" to have injectors/remap for a 19% but you will not get the full potential that the 19% has to offer without them. The MCS runs rich as a pig during WOT, so as long as you are not tracking the car with a 19% you should be fine.

 

Just out of curiosity- why not track a 19%? Belt fatigue? Supercharger wear at high RPMs?

 

It got so bad I just threw in the towel, and left a $100k+ a year job to spend all my time here for no pay!

Matt

 

So I guess this begs the question: In which situation do you find yourself as a happier, healthier person?

 

There is a supposed issue with water pump cavitation with the 19% at sustained high RPM.

 

so it's always a trade off! But this is funny, I start consulting for the same company (different group) at $1k a day today. So someone who couldn't do math very well still works there!

Matt\


back on topic. I don't know if the cavitation issue is real. There have been two camps on this one for ever. And those that spin the motor over 8000 RPM seem happy. You'd really have to watch water temps if you wanted to know for sure..... Also, at 19%, you spin the SC past 14,000 RPM at engine red-line, and that's faster than Eaton reccomends. But they're interested in the unit lasting well over 100k miles. So you trade a little lifetime for some more fun. Some think that the tighter bend of the belt on the 19 contribute to premature belt failure, but since it's such a cheap part, if you track your car put a new one on each season. It's a biatch if it busts on the track (And so embarrasing to get towed in.... Don't ask me how I know!)

Matt

 

It's because your water pump and your supercharger will be spinning at higher RPM's than they were designed to withstand. Not a good thing. Failure of these parts would be imminent if you drove them at redline for any sustained period of time.

 

While that is a prudent approach, I haven't heard of a single failure like that based on using a 19% pulley. And I've been watching for years.....

It's not like at 14,000 RPM the SC lasts 100k miles, and 14,001 RPM it blows up. None of use know the design buffer built into the parts, or how the lifetime vs peak RPM curve looks. But from reports of failures (or lack thereof) it seems like there is headroom available to use.

Matt

 

So I'm guessing a 19% pulley would work well for me; I don't spend much time in the upper rpm range, and I never track my car. Most of my journeys are fairly short, so I don't like to rev too high for fear of damaging a cold engine. Given that I do mostly city driving and rarely go above 5500rpm a 19% seems like a good fit. Am I right in thinking that it would really improve torque at lower engine speeds?

 

Can you (or anyone) tell me exactly how much less belt contact there is between a 19,17,15% and stock pulley? -- Johan