Underdrive Power Pulleys work to 'free up' horsepower. Any accessory that spins from the main drive belt is using up power. That's power that could otherwise be used to move the car. By giving some of that power back to the engine, you can make the car faster! It's like FREE HORSEPOWER! We measured 10.7 whp at 6960 rpm and 8.1 lb-ft of torque at 5550 on a 1995 M3.

Underdrive pulleys for your BMW will slow down engine-mounted accessories - the water pump, power steering pump, and alternator*. These systems contribute to 'parasitic losses' - power lost from what the engine could produce if it did not have these systems. Since less energy is used to move them, that power is transferred back to the engine and used to propel the car. Our pulleys give a 10-20% reduction in rotation, releasing up to 11hp on most BMW six-cylinder engines. There's also a small but noticeable improvement in throttle response too! We have done extensive testing and development work, both on and off the track, to ensure that the accessory systems function as they should. On our Racing pulley kits we actually underdrive certain components more so we feel our Street pulleys are an ideal compromise between power/torque gains, reliability, and system performance. Our pulley kits have been on the market for over ten years, and used in all of our own cars, with zero component failures related to their use.

Our pulleys are made from T-6061 aluminum and finished in a durable black hard anodize that is very resistant to wear, chemical exposure, and heat. We designed our pulleys to look similar to the factory parts but also to be stronger and, in most cases, slightly lighter too. For example, a Turner alternator pulley is less than half the weight of the stock steel pulley! With our hardcoat aluminum you will never have to worry about a serious failure of a stock plastic pulley. A 'stealth' approach to aesthetics was our goal and we let the results speak for the pulley design. Installation is straight forward and easy with simple hand tools. Removal of the fan is required for access to the front of the engine. Total install time for a 3-piece pulley set should be around 1.5 hours. A new longer belt is included and we also recommend replacing the separate A/C belt, belt tensioners, and the guide and deflection pulleys at the same time.

BMW M50 S50 S52 Turner Motorsport Power Pulley Kit: Boost Your BMW's Performance

• Increases horsepower and torque
• Improves throttle response and acceleration
• Lightweight design reduces rotating mass
• Precision-engineered for perfect fitment

Upgrade your BMW's performance with the BMW M50 S50 S52 Turner Motorsport Power Pulley Kit. This kit is designed to increase horsepower and torque by reducing the rotational mass of the engine's accessories. With improved throttle response and acceleration, you'll experience a more dynamic driving experience. The lightweight design of the pulleys reduces rotating mass, resulting in improved engine efficiency. Plus, each pulley is precision-engineered for perfect fitment, ensuring seamless integration with your BMW's engine.

Also known as a shock damper, the accessory belt tensioner is used to tension the air conditioning compressor belt. This ensures proper contact with the belt drive pulleys and prevents premature wear from improper tension.

If your belt is wearing prematurely or has excess slack, your belt tensioner may be to blame. Replace it with this high-quality Bremmen Parts tensioner to ensure proper tension and air conditioning functionality.

Service your drive belt system to prevent getting stuck on the side of the road. The tensioners, pulleys, and belt are all subject to failure over years of operation and excessive wear. This kit includes all of the replacements for common problem-parts to restore your belt system.

Kit includes:

2 Genuine BMW belts
Genuine BMW hydraulic tensioner assembly
2 Genuine BMW pulleys (one idler, one for tensioner assembly)
Genuine BMW A/C belt tensioner
Idler pulley bolt

The OEM INA Tensioner Bearing allows the belt tensioner arm to rotate and apply pressure to the serpentine belt. With a bad bearing, the arm may seize up and prevent the tensioner from working properly.

OEM Schaeffler (INA, LuK, & FAG) is an engineering company that focuses on high-performance, precision manufacturing. With their individual brands INA, Luk, and FAG providing exceptionally high quality parts directly to BMW, as well as countless other automotive companies, their history of reliability and variety of offered parts makes Schaeffler a go-to replacement parts provider for all of us here at Turner Motorsport.

As a leading source of high performance BMW parts and accessories since 1993, we at Turner Motorsport are honored to be the go-to supplier for tens of thousands of enthusiasts the world over. With over two decades of parts, service, and racing experience under our belt, we provide only quality performance and replacement parts.  All of our performance parts are those we would (and do!) install and run on our own cars, as well as replacement parts that are Genuine BMW or from OEM manufacturers. We only offer parts we know you can trust to perform