BMW Underdrive Power Pulleys

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!

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.

* Alternator Pulley Options

Bosch or Valeo? BMW built your car with either a Bosch or Valeo brand alternator. Unfortunately, the pulley is not the same for both brands. The brand is usually printed on the black plastic cover of the alternator but may be facing the frame rail or the ground. If you know which brand you have, select your option below and we'll send you the correct alternator pulley for your BMW. Don't know which you have? NO PROBLEM! We can send you both. The 2nd pulley costs $40 but you will receive a refund once we get the un-used pulley back (return shipping not included).

Stereo Systems. We offer our kits in two different ways: the full Power Pulley Kit with all 3 pulleys or as a 2 pulley kit if you do not wish to underdrive your alternator (for large stereo systems or other critical-charging modifications). Our kits have been tested for compatability with the factory premium stereo systems (Harmon Kardon, etc). But any major upgrades from the factory premium systems will work best with our 2 pulley kit and no underdriving of the alternator. For all stock stereo systems the full 3-piece set is recommended because the Turner alternator pulley will help make more power and is also much lighter than the stock pulley.

Additional Info

Clickhere for example dyno graph

Click here for installation instructions.

Turner Pulley Kit contents:

• Turner water pump pulley
• Turner power steering pump pulley
• Turner alternator pulley
• new extended length belt
• instructions
  
  
   
• This underdrive pulley kit fits the following BMW:
  1997-1998 E39 BMW 528i

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!

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.

* Alternator Pulley Options

Bosch or Valeo? BMW built your car with either a Bosch or Valeo brand alternator. Unfortunately, the pulley is not the same for both brands. The brand is usually printed on the black plastic cover of the alternator but may be facing the frame rail or the ground. If you know which brand you have, select your option below and we'll send you the correct alternator pulley for your BMW. Don't know which you have? NO PROBLEM! We can send you both. The 2nd pulley costs $40 but you will receive a refund once we get the un-used pulley back (return shipping not included).

Stereo Systems. We offer our kits in two different ways: the full Power Pulley Kit with all 3 pulleys or as a 2 pulley kit if you do not wish to underdrive your alternator (for large stereo systems or other critical-charging modifications). Our kits have been tested for compatability with the factory premium stereo systems (Harmon Kardon, etc). But any major upgrades from the factory premium systems will work best with our 2 pulley kit and no underdriving of the alternator. For all stock stereo systems the full 3-piece set is recommended because the Turner alternator pulley will help make more power and is also much lighter than the stock pulley.

Additional Info

Clickhere for example dyno graph

Click here for installation instructions.

Turner Pulley Kit contents:

• Turner water pump pulley
• Turner power steering pump pulley
• Turner alternator pulley
• new extended length belt
• instructions
  
  
  
   
•  
• This underdrive pulley kit fits the following BMW:
  1999-2000 E39 BMW 528i

Shark Injector Performance Software
The enthusiast's choice for over a decade, the Shark Injector's performance is only equaled by its own ease of install! Tune your ECU at the press of a button simply by plugging into the under-dash OBDII diagnostic port, there is no removal of your car's computer; no laptop or cables required. What does the Shark offer?

• Excellent horsepower and torque gains - peak: 18whp/11wtq, max: 22whp/16wtq
• Faster and smoother throttle response
• Top speed limiter removed
• Extremely easy to install/uninstall
• Reversible and reusable
• Elevated 8,250 RPM rev limiter
• Compatible with 91 octane; 93 recommended

​Turner Motorsport Power Pulleys 
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! We measured 10.7 whp at 6960 rpm and 8.1 lb-ft of torque at 5550 on a 1995 M3. Race pulleys deliver even more power. 

Another "no-downside" upgrade, we even include a new belt. Total install time for a 3-piece pulley set should be around 1.5 hours. We offer three options in pulleys:
1.) No alternator pulley included - for cars with big amps and powerful stereo systems that need the extra juice.
2.) Street Power Pulleys - our most popular option with no downside!
3.) Race Power Pulleys - delivering 15 "free" horsepower, this set underdrives the water pump, power steering pulley, and alternator for lower temps, less wear, and more power. Not for street use. 

Intake Air Temperature Relocation Kit
Looking to maximize your power gains? Add a Turner IAT Relocation to combat power-robbing heat soak - the only true plug-and-play solution available. Heat soak is a real plague on consistent power for a stock or tuned vehicle. Click here to read more about our IAT relocation kit.

This item fits the following BMWs:
2001-2006 E46 BMW M3

aFe Power's new power pulley brings performance engineering to your BMW M5. This power pulley is a complete bolt-on kit, including the pulley, bolts, and belts. aFe’s power pulleys are CNC machined out of billet aluminum and black anodized for that aggressive look under the M5’s hood. This power pulley does not modify factory harmonics or dampening. In recent Dyno testing this power pulley produced 5 HP and 6lbs. x ft. torque. When it comes to engineering for power, performance, protection and value, aFe Power is the only choice. 

This part fits the following BMWs:
2006 - 2010 E60 M5