A smaller supercharger pulley changes the drive ratio of the Eaton M45 supercharger in the MINI R52 Cooper S and R53. This makes the supercharger rotate faster and allows it to produce more boost pressure. The suitable reduction and the effect of the conversion depend on the condition of the MINI, the selected pulley size and the other technical components.
What does a smaller supercharger pulley change?
The smaller pulley changes the relationship between engine speed and supercharger speed. This allows the supercharger to respond more strongly and may noticeably change the power delivery. However, a fixed power increase cannot be reliably promised for every MINI.
- Higher supercharger speed: The smaller pulley drives the supercharger faster at the same engine speed.
- More boost pressure possible: Depending on the selected reduction and the vehicle’s condition, the engine may produce more power and torque.
- More immediate power delivery: The MINI may respond more strongly and directly, particularly in the middle of the rev range.
- Increased load: A greater reduction also increases the speed, temperature and load placed on the supercharger and related components.
Which pulley size is suitable for your MINI?
The KAVS Pulley Kit is available with reductions of 11%, 13%, 15%, 17% and 19%. The installation work is essentially the same for each size. However, the appropriate version depends on your expectations, the vehicle’s condition and any existing modifications.
A greater reduction is not automatically the better choice. The supercharger, belt drive, ignition and cooling system must suit the intended configuration. We therefore discuss which pulley size is appropriate for your MINI and its intended use before carrying out the conversion.
What do we inspect before installation?
Before fitting the pulley, we inspect the technical condition of the related components. Existing problems should not be made worse by the increased load.
- Read the fault memory
- Inspect the condition and smooth operation of the supercharger
- Inspect the supercharger belt, tensioner and idler pulleys
- Inspect the spark plugs and ignition system
- Inspect the cooling system and intercooler
- Take existing modifications and the vehicle configuration into account
If we find worn or unsuitable components, we discuss which parts should be replaced before or during the pulley installation. These additional parts and services are charged separately.
Pulley replacement or complete package
Supercharger pulley replacement from 299 €: This offer includes the KAVS Pulley Kit with your chosen reduction, the matching supercharger belt supplied with the kit, professional installation and a final test drive. The work usually takes around three hours. Software calibration is not included in this offer.
Complete package for 999 €: This package combines the pulley replacement with prepared software selected to suit the specifications of the MINI and a supercharger oil change. You should allow a full workshop day for the complete package.
Performance spark plugs can be installed on request at additional cost. Other components found to be worn or unsuitable for the intended configuration are also not included in the basic price.
What you should know before the conversion
No fixed power guarantee: The actual power increase depends on the pulley reduction, software, technical condition and other components. We therefore do not promise a fixed number of additional horsepower.
Prepared software rather than an individual rolling-road calibration: The complete package uses prepared software selected to match the specifications and configuration of the MINI. Individual calibration on a rolling road is not included.
Approval and road legality: Technical approval, inspection or changes to the vehicle registration are not included in our service. Before the conversion and before using the vehicle on public roads, you must establish whether the selected configuration is permitted and whether inspection or registration is required. Requirements differ between countries, and any necessary approval must be arranged by the vehicle owner.
Request a supercharger pulley replacement
Please include the vehicle details, mileage, existing modifications and your preferred pulley reduction in your appointment request. If you are not yet sure which version is suitable, briefly describe the result you want to achieve instead. The KAVS Pulley Kit can also be ordered directly from our shop without installation.