Hi guys,
I have my mini s at 75,500miles now. I want to start mod it with Alta v2 15% pulley since it is on sale at $89.99.
I believe my mini is still using the stock belt. I want to know which belt is the best combo to this 15% without noise?
i saw alta has the belt for 15%, also mossmini.com has it too. would like to know which brands are they?
I have searched and came up alot of options to choose from...
Also, should I get a new tensioner? and the tensioner stop too.
What else should I change too?
Thanks alot! -g

 

I use Alta's -15% v2 pulley and the JCW reduced length belt and to date have had no issues, this combination is no noisier than stock.

At the same time I fitted the pulley I also installed GTT's tensioner limit stop and a set of NGK BKR7EIX iridium plugs (i.e. one heat range colder).

The -15% pulley is a great mod for the Cooper S, put it on and enjoy .

Cheers
Darrin

 

Thanks Daza...!!
so a new OEM tensioner will be good enough?

 

It was once a widely held belief the JCW pulley was close to a 15% reduction in size and the JCW belt would be a near fit. Also, it was once thought the belt could stretch to a point within a ¼ inch of the stop limiter tab without experiencing belt slip. The actuality is the JCW pulley is larger than previously believed, and now that dynometers capable of high resolution have been utilized for the MCS, we know there should be a least part of the stop limiter strap’s top hole showing to ensure good tension on the belt to avoid slipping. The correct belt for the 15% pulley is NAPA 060535; this belt will leave most of the top hole showing.

A well used JCW belt over a 15% pulley.


NAPA 060535 belt with a few hundred miles of use.

 

Thanks so much!

 

gminiS, let me trot out my book answer for all pulley upgrades: Do the complete job.

By that, I mean buying some form of tensioner stop in order to avoid damage like this:

PICT1
PICT2

Details may be found here and here from this thread. Please learn from my experience, get some form of tensioner stop. This would have to be the only design flaw in our car but can be an expensive flaw. Cost me €650 or about USD$1100.

There are choices between the Detroit Tuned, Minspeed and Alta vendors; each are about USD$20. Cheap at the cost, especially before the fact!!

At the time of my mishap, Alta hadn't made their's yet, so the choice for me was easy: DT all the way. I preferred the ability of the stop to easily allow for belt stretch over time. Only natural for the belt to stretch but both the Minspeed and Alta appear to restrict that movement, which could/would/should lead to belt jump later on down the road. Only my opinion, however, pay the USD$20 now and avoid losing your car for a week whilst the dealership replaces all of these parts:

PICT3

FWIW, I was using the Goodyear Gatorback 535 belt which initiated the entire failure sequence. Since then, I've been with JCW belts, no problem.

Finally, doing this job absolutely requires the right tools. There are two specialty tools required for the job: a tensioner release bar and a pulley puller. My buddy Henry, an Army mechanic, helped me make my own tensioner release from a fence gate hinge arm. Just a four foot piece of steel with a couple of holes drilled for some bolts. Cost about USD$15 vs. €120 from the dealer. Trick is to get the alignment to the tensioner arm correct. The pulley puller, on the other hand, is where it gets expensive. About USD$110 but, again, cheap at the cost. Otherwise, if this job goes wrong, it can really get expensive. This is the best tool I've seen and would get it myself once I get back to the States.

gminiS, I'm sorry for the long dissertation, however, I hope that you learn from my experience. Do the swap, enjoy the drive. Just do a complete job!

Cheers!!

 

A puller that only grabs one half side of the SC pulley like the Madness version (aka Deluxe from other vendors) linked in the previous post is only good for average pulley removal difficulty. Some pulleys require more effort; the half grip style will deform the pulley creating more problems than the convenience of leaving the tensioner on is worth. One can not predict whether their pulley will be of the unfortunate few.

 

Thanks guys!

 

Not meaning to hijack this thread, I too am installing a 15% pulley in my MCS next weekend...along with Inspection 2. My MA quoted me JCW plugs at an outrageous price and told me I could bring my own plugs in. Also I too am debating the belt issue. Should I just use the JCW belt or drop by my local NAPA.

In researching plugs, I went to a friend who is a parts guy at a local Vancouver aftermarket place and asked about spark plugs. Denso IK22's are 1 temp lower than stock but he does not have them. But a check on realOEM says my MINI came with NGK BKR6EQUP and the JCW plugs are NGK BKR7EQUP. However, the JCW plugs are not on the catalog. My friend told me NGK6EQUP is the coolest temp plug that NGK makes and is their premium plug. RealOEM has the JCW plugs as no longer available since 2005.

Are the NGK BKR7EIX mentioned earlier the replacement for the BKR7EQUP?

I'm wondering if the JCW spark plugs are just the stock ones. MINI's quote on them had me wondering if they are outrageously priced.

 

hi, i will get the JCW belt with my 15%.
I am always shopping for the colder spark plugs,
here what i found from minspeed.net, these are NGK BKR7
They claim these are the same with JCW plugs.
-g

 

I ordered the BKR7-EQUP plugs, with no problem, from www.sparkplugs.com. Smoothed out my idle, pulls with no stagger now that I've installed them (using a 15% pulley).

Due to other users' statements regarding the Denso plugs, I would never recommend them. NGK's, Brisk, and Bosch seem to be working out fine. Seems that all blown spark plugs seem to begin and end with Denso's being involved. I'd steer clear.

- Matt

 

The photo in post #4 illustrates why the JCW belt is not appropriate for the 15% reduction pulley. In the presence of photo evidence, why would you choose the longer JCW belt?

 

Your photos are comparing a "well used" JCW belt with a NAPA belt with only a few hundred miles. To be fair you should be making this comparison after both belts have travelled the same distance.

That said my JCW belt has travelled a few thousand kilometres and the hole is still visible and I've never experienced belt slip. I'm not saying the length is optimal but it's better than using a stock sized belt - which most people think is fine to use - and I have the confidence of using an OEM part.

Regardless of which belt you choose it should be changed at regular intervals. Once the hole in the tab is no longer visible it probably just means it's time to change the belt.

 

Have you dyno'ed your car routinely? Otherwise, how would you be aware of belt slip?

- Matt

 

Put the car on the dyno when I installed the pulley to ensure that the stock map would cope with the modification. Now I monitor peak boost at WOT to ensure everthing is still working - no belt slip, boost leaks etc.

There's no way in the world I would dyno my car on a regular basis! The poor little thing has to work pretty hard on the dyno, I wont subject my car to that torture routinely.

 

This past spring I installed a new drive belt tensioner(old shock leaking) and I put on another new JCW belt. The photo below is where it was from the get go.

The hole is barely visible now after 4000 miles or so, which was just like the stock belt with 15% SC reduction pulley.

I'm with K-huevo-I'll be trying a slightly shorter belt next time(even though I found that the Napa 060535 is 1379mm whereas the JCW belt is 1374mm). Standardized belt measuring??? I don't know.

Jeremy

 

Which tensioner stop does everybody recommend? I heard some of them rattle and are quite noisy?

 

I have had zero problems with my DT, recommend it to others and would do it again. Does that help?

Cheers!!

 

i finally recieved my alta tensioner stop a week or two ago (about 2 months after i installed my pulley). Do i have to jack my engine up to install the stop like i did to install the pulley or is there some other way that's easier and would take less time to install?

 

I was able to mount my DT without lifting the engine, however, some folks haven't been so lucky. The tricky part, if I recall, was the lower bolt on the tensioner arm. It is very close to the frame rail and difficult to remove without lifting. Good luck!

Cheers!!

 

I know that Poppa bear had had issues with goodyear belts. I would like to reinerate that idea. I have had nothing but problems with the gatorback brand. I jumped time in my eclipse due to a "faulty" gatorback it was used less than 5 miles shop installed, before that I had shredded at least 3 accessory belts from goodyear, all with low miles. I switched to a house brand and never had a problem. SO if you can avoid using the goodyear brand belts.

 

So I had my pulley installed last Friday.

http://www.flickr.com/photos/beken/3037560562/

I suspect they may have changed the tab on the tensioner on the 05 model year because there was no hole near the top of the tab. If I were to get a belt short enough to show the top of the first hole, the spring would be completely compressed.

That hole is about an inch down from the top of the tab.



I had originally bought a NAPA 60535 but when I opened the pulley box and read the instructions, Alta recommended a 60539. So I emailed and to Alta's credit, they replied within an hour . They said the 60539 was the correct fit but the 60535 would fit also, but would be tight. So I exchanged for a 60539. I will check where the end of that tab is somewhat frequently and hope I didn't do anything wrong following Alta's advice.

Even more puzzling, the MINI dealer felt the stock MCS belt would still work with a 15% pulley.

I also followed the advice given here regarding spark plugs. I installed NGK BRK7EIX plugs.

Thank-you all for your helpful discussion.

 

I got a the gatorback back belt installed as it's the only local belt I could get within 2 days. The others I would have be bring in from the States. It was the 4060537 belt and it JUST JUST fit. The coil is compressed at it's maximum. I've got only a 17% SCP installed.

 

That would mean two holes in the stop limiter strap are showing; interesting, as I used the Gatorback 537 on my former 19% and have installed on another's 17%, just barely one hole was showing after a weeks driving on the 17% and partially showing on the 19%. It's a little long for the 19% but just about right for the 17%.

There has been no tensioner change across R53 model years. As beken discovered, the NAPA/Gates 539 is too long for the 15% reduction pulley.

 

Interestingly enough only one hole shows, but there is some a gap between the hole before the spring.