1st Gen R53 Cooper S Most liked posts in thread: Another pulley question

A tensioner stop is only helpful if you a have a light weight alum crank pulley. the ATI and others like it are Metal and it will not get damaged if the tensioner does fail, but more than likely it's because you need a belt. inspect the belt often and you will not have a problem.

Chad
Detroit Tuned

 

Stay with a 15% pulley on the OEM Eaton M45 for reliability.
17 & 19s spin the blower to fast and can cause pre mature blower failure.
Yes a 17 or 19 will make more power but for how long.....

As for a crank damper just stick with the OEM size and get the STI Super Damper or the PRW Fluid Damper. You do not need oversized damper you just need to get rid of the OEM cheap rubber one that will fail.

While you are doing the above you may as well change your idler pulley and OEM tensioner. (Hint) You can buy the exact same tensioner part that the dealer sells for over $100 less then the dealership parts counter.

15% Helix pulley: Helix MINI Cooper Supercharger Pulley

Tensioner: http://www.amazon.com/dp/B001KSDZOY/ref=wl_it_dp_o_pC_S_ttl?_encoding=UTF8&colid=1JEWSSABUMWXR&coliid=I3JTHYYA18GZ33

Idler pulley: Amazon.com: Gates 36168 Idler Pulley: Automotive

15% pulley belt: Amazon.com: Gates 36168 Idler Pulley: Automotive

 

Back to the OP........

15% vs 17% is really going to come down to how well you can manage the heat generated AND what part of the rev range you will be realistically driving in.. In Texas I would never suggest going with the 17% as the heat generated could be excessive. You could stay well below the upper rev limit with the 17%, but what fun is that.....LOL

 

Just pack up what tools you need and find a mall parking garage for a few hours.

If mall parking lot security stops by just tell the security guy you have to fix it so you can drive it home and ofer him a donut.

 

Sure those titanium bolts would be nice, but at that cost it's crazy money for such a small gain or maybe no gain at all.

While you are there changing the damper it might be a good time to replace the belt tensioner & idler. After doing those my MINI engine seems smoother.

 

From what I've read stock to a 15% pulley is 4psi. As you know the more pressure the more power. But you will also stress the motor more.

Keep in mine more boost is more air and past about 15% you will want to consider more fuel. (bigger injectors) Also the higher pressure generates more heat.

So it's not as simple as bolting on the biggest or smallest pulley it's considering the the package and what you want to achieve.

 

I also say Dave is correct. I went through all this in stages. After the 15% pulley and RMW Dyno Tune, I replaced the Harmonic Balancer with the ATI SuperDamper from Way Motors. He said the ATI Damper stock size is 0.8% larger than OEM, and gives another 1/2 lb or so of boost, which would translate into a few more HP, and result in about 16% increased spin including the pulley.

Maybe it's my imagination, but the motor does seem smoother and more rev-happy with the superdamper. Anyway, I'm sold and the car seems happy as well.

Reliability is a big deal to me, and lack of it seriously detracts from the joy of the Mini experience, as I want to be able to jump in any time and drive 1,000 miles with no issues. I've put almost 50K miles on it since 2010, and except for the MDX fiasco, and iridium spark plug issues, the car has had no issues.
And I don't like doing much more than adding more layers of carnauba wax, steam-cleaning the motor, and shampooing the interior.

 

A note about the titanium bolts for the ATI Crank Pulley. No they are not needed, Unless! you need to remove it several times and end up breaking the stock bolts in it. They come with good hardware and will not break unless used over and over again. Like most bolt that are under stress on the engine, it's best to replace them with new ones when there is the need. We stock 10 dampers and only two bolt kits, so must people don't need them over all. but it's best that we have a few of everything in stock when you need it...we have it. But to the pulley question..i have always liked the 15% on the supercharge and 0% or 2% for the crank..but it's all a personal preference and you can run more if you take the right measures to keep things safe. But again we stock 20 15% pulleys and 2 17% pulleys..just cause.

Chad
Detroit Tuned

 

A 17% can be safe...depends on driving style and mods...
I ran a 17% untuned, no injectors for a bit...did make me nervous at higher rpms...
But with a tune, it is great if you don't rev the snot out if your car....
So a 17% CAN be a great size on a daily for the right person....
100% get a dampened crank pulley of some type...IMO, stay with stock size....

 

I've never thought those under-drive crank pulleys were good for an engine. Since the designers of the engine spec'd a damper going with an ATI crank damper is a good move.

If your MINI is your daily driver don't make the mistake of modding it to the point of not being reliable. Once you get past that sweet spot it can become a problem. Lots of good advice given in this thread.

No mater what you do a good tune will pay dividends.

My .02, if you are going to track your MINI the sustained high RPM & 17% may not be a good choice.

 

If I had a 17% on my car I would always run the snot out of it just because I had it and I would have destroyed my blower or more by now. :lol::lol:

My theory was why install something if I cant hammer to the floor every time I want to. :ihih:

With a 15% and my mods, tune and my red line now set about 8K I can safely beat the snot out of my car anytime I want without any worries.

Well one worry, I need to make sure I have a full tank of Meth.

 

Not really, but a nice new bolt came with mine. (Not Lightweight Titanium)

I just think $50 for 1 bolt is a little much. :nonod: