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MF Review: Webb Motorsports 15% Pulley

Since the introduction of the Cooper S in 2002 people have been finding new and improved ways to gain horsepower. New exhausts, upgraded air intake systems, modified ECUs and a host of other additions can help satisfy that lust for more power. Yet there’s one magic bullet in the MINI aftermarket that is head and shoulders above the rest in creating power: the super charger reduction pulley.

Warranty and Reliability

Before I get to the actual review, let me touch on what a reduction pulley does and how address a few concerns owners may have.

The principle isn’t new. Simply decrease the size of the stock supercharger pulley and you’ve got yourself a more powerful Cooper S. Dynos show gains on a 15% reduction pulley (the most popular size on the market) can over 15bhp. So with one modification your stock 170bhp Cooper S can go to 185bhp. And it gets better. The Webb Motorsports 15% Pulley tested retails for only $120 (other pulley’s msrp for about the same).

So you may be asking, where’s the rub? How is it possible that something so cheap, simple and small can add so much? The first obvious concern is warranty and reliability. The reliability question is easy when it comes to a 15%. With the JCW upgrade using a 14.6%, it’s obvious that the 15% falls well into the safe category of modifications. With MINI testing and re-testing the JCW pulley size the world-over, you can expect a pulley .4% smaller will perform the same. In fact to my knowledge (and I may be proved wrong in the comment section at some point) there hasn’t been one case of mechanical failure that was the direct result of a 15% pulley.

Now onto that pesky warranty question. MINI has left it up to each dealer and then it’s regional reps to determine if and how a pulley may have effected any mechanical failure. While I’ve never heard of this actually happening, it is technically possible for a particularly uninformed or ignorant MINI Service Advisor to use the appearance of a reduction pulley as a scape goat to deny warranty coverage on a few related internal components. It’s rare but it has happened in a few cases. To deny warranty coverage on the entire car due to a reduction pulley is just about unheard of.

It may be worth mentioning that Webb Motorsports warranties their Pulley for 2 years/24,000 miles or the remainder of your factory warranty. Some other vendors offer similar warranties.

But enough about who covers what, let’s talk performance!

Webb Motorsport Pulley Performance

Wow. That was all I could say after my first test drive. The car was eager, quick, and pulled hard all the way to redline. I could feel the difference immediately and it was impressive. In fact I was toying with simply having one word for this entire section of the review. For the longest time I couldn’t think of anything more to say than; wow.

Think about how much fun it is to row through the gears of a Cooper S from 0-60. Now add 15hp throughout the entire powerband. Or consider this; from a standing start with DSC off my Cooper S with a JCW intake, Supersprint exhaust and now the 15% Webb Motorsports reduction pulley, will put a healthy amount of rubber down in first gear, second gear, and (if I wasn’t there I wouldn’t believe it) third gear. The car feels more eager and pulls hard all the way to redline (which by the way you’ll want to watch out for a bit more with a 15%).

Or you could just say; wow.

Webb Motorsports Pulley Design

Randy Webb has been installing and designing pulleys for four years now. First it was in conjunction with Alta. However now Randy has his own design and it features a couple of unique design traits. Here’s how Randy explains his pulley design on webbmotorsports.com:

First, it is all steel. What that means is that the thermal expansion rates are the same between the pulley, the hub of the pulley, and the shaft of the supercharger. That becomes very important when the temperature deltas can vary by as much as 300F. The same thermal expansion rate means you won’t have to worry about the stability of the taper bore fitment on the shaft, or the tension between the hub and pulley.

Secondly, it is stainless steel, so the unit will not corrode over time like aluminum and mild steel do.

Third, it uses a positive stop on the inside of the pulley, so the hub is always in the right spot.

Fourth, the end of the pulley is capped, so as long as the hub is pushed all the way onto the shaft, the pulley will always align itself as it pulls the hub into itself. After having done over 800 pulley installs, I have never seen more than .02″ difference between these – the belt is always perfectly aligned.

We have several unique features on our pulley as well. We have machined a center hole to both reduce weight, and allow for easier tolerance checks. We have also worked hard at reducing the radius and therefore rotational mass.

Finally, this is a taper bore style pulley, rather than a heat and press interference type pulley. This pulley is installed at room (or shop) temperature.

As you can see in the picture at the top of the page, the Webb Pulley is almost jewel like compared too the stock piece. It’s truly a piece of art.

The Pulley Conspiracy Theory

As part of the design process for the pulley, Randy Webb did some research into this subject (w/the help of Eaton who manufacturers the MINI’s supercharger) and found that a 15% reduction is really the optimal size in regards to the powerband. So this begs the question; why didn’t BMW simply give the Cooper S a smaller pulley from the start? There are a couple of theories. The one I subscribe to goes like this: BMW didn’t want to increase an already large power gap between the Cooper and Cooper S. They also wanted to protect the low-end 3 series and the (at the time) soon to be released mid-range 1 series. By capping power on the MCS to 170bhp they are able to slot it in nicely the other cars’ offerings. They also give the JCW plenty of room at 210bhp. Helpful when you’re charging around $6,000 for the Works upgrade. Again this is all just a theory, but I know quite a few people in the industry that believe it.

Conclusion

The Webb Motorsports Pulley is an addicting, neck snapping addition to the Cooper S that simply can’t be matched by any other modification I’ve experienced. With very little to be concerned about in regards to warranty, it’s an addition that shouldn’t be overlooked when modding a Cooper S. While it doesn’t turn your car into a JCW beater, it gives the Cooper S the power that it deserved out of the factory. It’s like flipping a extra special secret switch that MINI doesn’t want you to know about. It’s also just happens to be the first product to ever recieve a perfect score in a MotoringFile review.

MotoringFile Rating: 5 (out of five)

Where to Buy: The Webb Motorsport Pulley retails for $120 and can be purchased from Webb Motorsports. Several other MotoringFile sponsors carry a similar pulley as well. Promini, Helix, Outmotoring and MyMini all carry 15% pullies and M7 carries their own 16% design.

Written By: Gabe

  • Jac

    it’s all been coverd many places, but the JCW kit gets you

    • new SC (same as a 05/06 SC, only with the smaller JCW pulley) • new head (port & polish?) • new intake • new injectors • new JCW ecu flash/programming to make it all work together • JCW catback exhaust • complete warrantee • (anything else?) – i think brakes & Susp. if you order it from the factory, but i guess most people here already have thier MINIs….

    it’s perfect for some folk, not for others. (don’t want to debate that one!) Neither is right or wrong…no flames please.

    Anyway, for many people, the reduction pulley gets a good amount of these gains with “minimal” risk at only a small porion of the cost of a JCW kit. in all my reading the 15% & 16% (M7) pulleys have had little problems, and they have been installed on many, many MCSs. I think randy did well over 6-700 himself. (not to mention all the other tuners, people who have done them at home, etc.)

    For me, the JCW kit is out of my price range. I have an alta CAI, a R-speed MCS exhaust, and I will be adding a 15 OR 16% pulley in the near future. For me, this will get me where I want my daily driver 06 MCS for under $1000.

    YMMV.

  • Lex

    I own a 05CS with a 15% pulley. Just 2 weeks ago the Service Manager for Braman MINI here in Miami FL refused to check a DSC error because of my pulley. “I CANT touch your MINI for any problems until you remove the pulley. I CAN provide you with scheduled service only”… YEAH RIGHT!

    He also told me that my Magnecor plugwires could render my electrical system out of warranty…riiiight!.

    Am no longer a client. I drive an additional 20 miles for honest service.

    So if you are thinking about getting a pulley installed, check with your local dealership and see how they feel about it first. IMHO the pulley has been my favorite pwr mod so far, and worth the extra drive.

    And for all you potential MINI buyers in the Miami area who are planing to MOD, beware of Braman MINI.

  • Dave S.

    Gabe, your review is spot on. The 15% pulley is 5 out of 5 and makes the MINI-S the way it should have been from the factory. We got our Alta 15% pulley installed in March by Chad at Detroit Tuned and it is by far the biggest bang for the buck mod for the MINI-S.

  • David

    Does anyone out there know if California MINI drivers will have smog check issues if they install the 15% pulley? I’ve noticed that most of Dinan’s MINI performance mods are approved in 49 states, excluding California.

  • Brian

    LEX – Who is your service manager at Braman? I always go there and im thinking about getting a pulley soon. Which dealership r u going to now? Brian.

  • Frank

    It seems to me that Lex is taking his MINI to Lauderdale MINI in Ft. Lauderdale, FL.

    If you are up that way, see Lamont Thomas for the best service experience in South Florida.

  • Brian

    Frank – I sure will, Thanks

  • Homer J

    For those of you asking about the 15% pulley on an MCSa, you WILL feel the extra power. A little more involved to install though. Randy did mine back in February and it’s by far my best mod.

  • GOODRICH

    Gabe did you install it yourself? If so how difficult was it really. Me and a couple of buddies were going to do it within the next couple weeks to my car, and I’m kind of scared that I might mess it up. Should I be? I think I’m better off with going with the Webb Pulley because it seems like it would be a no brainer to seat it right.

    Thanks

    G-Rich

  • Rossii

    “Anyway, for many people, the reduction pulley gets a good amount of these gains with “minimal” risk at only a small porion of the cost of a JCW kit. in all my reading the 15% & 16% (M7) pulleys have had little problems, and they have been installed on many, many MCSs. I think randy did well over 6-700 himself.”

    I agree to be on the safe side either the 15% or 16% is fine w/o any warranty issues. I had the Alta 15% on my 05 and M7 16% on my 06 which Randy installed at his last pulley party in the SF Bay Area. His total is 795 pulleys mine being 794. :)

  • http://www.markscheuern.com/ MarkS

    Excellent writeup. I’ve got the 15% Alta (expertly installed by Detroit Tuned) and couldn’t be happier. And, forgive the geekiness but a 15% pully is actually about 3% smaller than a 14.6%; it’s 0.4 percentage points smaller, not 0.4%. I obviously agree that if 14.6% is safe, 15% should be, too.

    Mark

  • jac cottrell

    Rossil – any noticible difference between the 15 & 16? I am really not expeting any…..but i like the shoulders on the M7 pulley.

    Had some bad belt throwing exp’s once…. :)

    thanks!

    -jac

  • http://www.motoringfile.com/ Gabe

    jac – either are fine products and will work great but there is a specific reason why the Webb is designed the way it is.

  • Brad

    I just picked up my 05 MCSa from service after my 15% Alta pulley “spun on the shaft” and gouged and scarred the shaft and the SC housing. The pulley was installed by me and my nieghbor, who happens to be a Mech at the local Jaguar dealer. Everything seemed to go great, and I had 1000 miles on the new pulley. While it worked, it was amazing.. felt like the car just wanted to go and go and go. But then a buzz developed at high revs. I really thought it was electrical noise coming through my stereo. Visually nothing under the hood seemed wrong. But then last Friday a Horrible noise and off to the dealer. So new SC along with the stock pulley and a few thousand dollars later I’m back to stock. Not sure what I’ll do now.

  • http://www.miniyaletown.ca David L.

    Not trying to give you any ideas about how to get around warranty issues with your dealer, but if removed, are the stock pulleys able to be replaced if issues with the SC develop? Say you experience problems like those mentioned, bearings go, pulley slips off, belt frays, etc. Can you just reverse the pulley swap and slide your MINI into service without too many questions being raised? How could the service figure out you had an aftermarket pulley if they don’t see it?

    I and a few other Vancouver area MCS owners are figuring to have a local installer (Bishop’s in North Vancouver) do some Alta 15% pulleys installs for us. I drove a JCW at Zandvoort in Amsterdam and ever since I got back I’ve been itching for more juice from my MCS.

    Regards, David, MINI Yaletown 05 MCS BEP

  • http://mini2.co.za Timmee

    What pulleys are available outside the US? Any local installers in South Africa?

  • Jac

    Gabe – what specific design points are you referencing here?

    i have poured over the pics, old threads, etc of all the major pulleys. Curious what makes webb all that different.

    I know the Webb pulley:

    • is stainless steel, two piece with a positive stop on the inside for correct installation (as are alta, helix, m7)

    • hole in center to check tolerances (helix too)

    • 4 bolt (alta, m7)

    what else?

    I am sure that each one of the brand name 15(16)% pullies are fine….

    I am split between the helix, webb, & m7. Helix is local, webb is webb, i like that m7 is 16%. (and i like thier logo too….the designer takes over again….) I already have an alta intake, so i need to support someone else! :) My MINI is equal oppurtunity! :)

    Thank you for your input – and feel free to go offline if it is not something that needs to be discussed here.

    • Jac
  • http://www.motoringfile.com/ Gabe

    I am split between the helix, webb, & m7. Helix is local, webb is webb, i like that m7 is 16%. (and i like thier logo too….the designer takes over again….) I already have an alta intake, so i need to support someone else! :) My MINI is equal oppurtunity! :)

    Jac – I would say you’ve done more research than 99% of the people out there. So with that said you are in a great position to chose which one makes the most sense. With Helix being local, my first thought would be to let the guys there take care of you. They’ve got a great reputation and their products are top-noch. But then again I always try to keep it local if I can :-)

    Everything seemed to go great, and I had 1000 miles on the new pulley. While it worked, it was amazing.. felt like the car just wanted to go and go and go. But then a buzz developed at high revs. I really thought it was electrical noise coming through my stereo. Visually nothing under the hood seemed wrong. But then last Friday a Horrible noise and off to the dealer. So new SC along with the stock pulley and a few thousand dollars later I’m back to stock.

    Brad – I’m very sorry to hear about your issues. A pulley install, while seemingly simply, is a very tricky thing for someone who’s never done one before. Even for someone who is very experienced in other matters automotive. I’ve seen Randy do enough of them to know that there is an art to doing it and that there are some very specific things to avoid doing. Best of luck with everything.

  • Jac

    yeah – i spend a bit of time doing research…. I can never figure out if i enjoy that part more than the parts themselves! :0

    thanks for the input!

  • Brian

    Hi People, Im considering getting the My Mini 15% pulley since they’re located here in South FL. You know of anyone that has that pulley installed? Anyone have any comments on it? Thanks.

  • http://www.motoringfile.com/ Gabe

    MyMini has some great products and I’d highly recommend them. If they’re local to you, all the better!

  • http://none fernando apaez

    I live in Mexico and I got a 29% smaller pulley and ecu tunnig, the car runs brutally.

    I used to have a 2004 manual transmission Mini and it was able to spin (a bit) the tires from 2 to 3rd gear. I smashed that car and now I got an automatic one, cause the ultra hyper intense traffic in the City, and the car (also with the pulley and ecu mods) runs amazingly. At this altitude 2250 meters over sea level, a Golf R32 can´t beat me 1st 2nd 3rd gear, even though the auto transmission

    The dealer is del Rio Power, he rocks!!!

  • http://www.miniyaletown.ca David L.

    Err, 29% or 19% reduction? Or are you just running the belt on the supercharger shaft? ;-)

    Regards, David, MINI Yaletown 05 MCS BEP

  • somake

    Iaorana guys !

    What about a 19% on a jcw210? a real piece of art ! anyone tried that ? is the jcw pulley easy to remove ? is it worth it ? i guess the engine could stand it better than the standard mcs ? what should be also upgraded ? And the jcw upgrade to 225? any experience ? Two friends of mine are mcs with 15% and it ‘s really great . still behind , but much closer … Great sound (with bmc intake) a real motorcycle this car !! I have to improve my english to write it up ! Well thanks again gabe . your black mini is “magnifique” . See u.

  • Kurt

    Hey guys!

    I just purchased the M7 pulley after way too much research. I too was taken with the design (and that cool 16% engraved on the side) The M7 guys recommend using the JCW belt with the pulley which makes sense. My dealer is going to do the install for a reasonable amount of $$$$, and I’m looking forward to experienceing the flip of the “secret switch”!!

  • Jim

    With the 15% Webb pulley do you need to do a software download?

  • Diam

    I am thinking of installing a 15% pulley on my MCS, but still don’t whether I can do that without installing a new ECU (or a remapped one). Is it necessary to have both? because if it is you need a considerably larger amount of money spent.

  • Ken
    Gabe did you install it yourself? If so how difficult was it really. Me and a couple of buddies were going to do it within the next couple weeks to my car, and I’m kind of scared that I might mess it up. Should I be? I think I’m better off with going with the Webb Pulley because it seems like it would be a no brainer to seat it right.

    Your write about the no brainier part for seating the Web Pulley, I did the install with Randy looking over my shoulder or well sometimes I was looking over his. I have some mechanical experience so it helps to know what is too far when working on things. You’ll need a few special sockets to fit in tight places but it was worth the effort and satisfaction of a clean self install. It pays to use a puller that will gently remove the original pulley and it has to be dead center so that you’re not bending the shaft. And no pry bar should be needed; you’ll mess with the SC bearings.

  • Ken

    Opps, that should read You’re right about the web pulley.

  • Mark M

    I just ordered the 15% pulley from the WebbMS site but now realize that the pulley is for 02 – 05 Cooper S. I have a 06 Cooper S. Will this Pulley work with my 06? (I didnt see any pulleys listed on the WMS for an 06 Cooper S)

    Thanks in advance.

  • http://www.motoringfile.com/ Gabe

    Mark – yes it will work on an ’06 as well.

  • holdenontoit

    I have made RANDY 10 removal tools and it is my understanding that he loans them out if you buy the pulley from him. For all who are interested, I rent and sell these tools ($30/$60) drop me a PM on NAM or MINI2 if interested . Jock

  • http://www.helix13.com Dane Helix

    The JCW is 13.8% reduction.

  • Liam

    Nice review. I’ll be fitting a 15% ALTA pulley within the month and am really looking forward to it.

    I was interested to note there was no mention of an ECU upgrade to deal with the new pulley, and other mods the car has. Are you planning an ECU upgrade at all? If so I can’t wait for your review. :)

  • Nav

    If istalling a 15% pulley (considering MiniMania or Webb) do you need to change to cooler spark plugs and 8 mm wires?

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  • GUILLERMO

    IS IT VERY HARD TO CHANGE THE PULLEY? CAN I DO IT MY SELF? DO I HAVE TO LOWER THE ENGINE TO REMOVE IT.

    TAHNKS

  • Pingback: 15% Reduction Pulley for 06' MCS - MINI2 - MINI Forum()

  • Nathan

    Thanks for the review! I just wondering if there are any other modifications I would need to do to get the utmost reliability form the pulley? Is there anything that needs to be done to the fueling to go with the pulley?

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