A 15% reduction in the supercharger pulley diameter of the MINI Cooper S increases the boost of your MINI Cooper S by more than 4 pounds, resulting in a dyno-measured gain of over 20 horsepower AT THE WHEELS. Maximum boost is achieved at lower RPM, giving more power in the mid-range of your MINI Cooper S.
Fits 2002-2006 R53 MINI Cooper S and 2005-2008 R52 MINI Cooper S Convertibles.
Does NOT fit 2007+ R56 MINI Cooper and S, and does NOT fit the R55 MINI CLUBMANS.
[ ] Unique 3-piece supercharger pulley self-aligning design delivers superior clamping force, and doesn't pull back from the stop when tightened like 2-piece designs.
[ ] The new built in stop locates the supercharger pulley in the proper position, simplifying installation.
[ ] Optimum 15% reduction avoids over-spinning supercharger and excessive intake charge heat generated by smaller supercahrger pulley upgrades.
[ ] Includes correct length belt for proper tensioner operation.
[ ] Lightweight design with low rotational mass spins up faster than heavier steel supercharger pulleys.
The removal of the stock supercharger pulley requires a special pulley removal tool. If you are considering our pulley upgrade, take a look at NMK5041 for a kit that includes a rental pulley removal tool.
How Small is Too Small?
Supercahrger pulleys reduced 16%, 17% or 19%, or using an oversized crank pulley, may spin the supercharger faster than our 15% pulley, but most of the additional boost cannot be used and can contrubute to engine and exhaust system damage. These smaller pulleys cause the supercharger to operate at higher RPM than it is designed to tolerate at redline. Plus, the Roots type supercharger drastically looses efficiency at higher RPMs, generating excess heat as it tries to compress more air. In the process, it further overloads the barely adequate air-to-air intercoolers and causes the ECU to enrichen the mixture and pull back on ignition timing to preserve the engine. This results in lost power, poor fuel economy, lower reliability, the potential to 'meltdown' the catalytic converter and higher emissions.
At 15% reduction, this supercharger pulley provides the most boost increase available without over-revving the supercharger at high engine RPMs. This ratio gives you added power without undue stress on the OEM supercharger or other adverse effects. Remember, if you're looking for performance increase AND reliability backed by the best Warranty in the industry, the 3-piece pulley upgrade system is the right choice for you and your MINI Cooper S!
And Lighter is Even Better
Compare our supercharger pulley's 7.8oz. low rotational mass design to competing all steel designs, weighing as much as 15.6oz. The ULTRIK 3-piece supercharger pulley system concentrates the weight near the treated steel center, incorporating lighter weight aluminum alloy material at the circumference, accomplishing an inertial mass 4 times lower than the 15.6oz pulleys. Ask others how much their supercharger pulley weighs. It spins very fast, so don't accept that additional mass is insignificant. Use our lightweight pulley along with our lightened crank pulley to really reduce rotational mass and improve acceleration.
All steel clamp design has similar thermal expansion rate as the supercharger shaft to maintain superior clamping force over entire operating temperature range.
The three-piece unit allows easy installation of the supercharger pulley onto the shaft without a press and enables easy removal. "Three pieces for a reason", our hydraulic press tests show the 3-piece pulley design superior to other tested 2 and 3 piece brand name designs. We won't mention names here, but we've tested all but the cheap knock-offs.
Locating the pulley on the shaft is easy and reliable, simply run it all the way onto the shaft until it stops. Proceed with tightening the bolts in sequence and the unique 3 piece design clamps down relentlessly on the supercharger shaft, without pulling against the stop.
This kit includes the correct length belt to keep the tensioner centered in its range, is best for performance and reliability.
See NMK5041 for a kit that includes the high quality 3-piece self-aligning supercharger pulley (2.19" diameter), shorter belt and a rental pulley removal tool.
See also NME5018 for Pulley Removal Tool by itself, or the NME5990 for Belt Tensioner Tool.
We recommend the belt be inspected regularly and replaced once a year.
Click Here for Installation Instructions 1
Click Here for Installation Instructions 2
Check local regulations on conformity for street use.