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

High performance ignition kit for your B46/48TU featuring spark plugs, Turner high performance ignition coils and dielectric grease to make sure you have no issues at your next maintenance interval!

Our BMW ignition coils are designed with performance and efficiency in mind. An engine needs 3 main components to run (Air, Fuel, Spark.) Turner ignition coils are modified to increase energy output; more energy output results in a faster, more efficient and consistent burn to make sure your fuel is being utilized to its maximum potential. Our signature Turner ignition coils feature a blue housing that give your engine the performance and aesthetic your looking for.

Ignition coils should be changed every 40,000 - 60,000 miles and are an important maintenance item due to the essential role they play in your engines health, performance and efficiency. Choose Turner Ignition Coils to keep your engine running strong and healthy.

Features and Benefits:

Increased performance
New spark plugs and grease
Direct fitment
Signature Turner Blue ignition coils

Our B Series ignition coils are designed with performance and efficiency in mind. An engine needs 3 main components to run (Air, Fuel, Spark.) Ignition coils are responsible for 1/3 the operation your engine and it would be smart to weigh the options when shopping. Turner B Series ignition coils are modified to increase energy output; more energy output results in a faster, more efficient and consistent burn to make sure your fuel is being utilized to its maximum potential. Our signature Turner ignition coils feature a blue housing that give your engine the performance and aesthetic your looking for.

Ignition coils should be changed every 40,000 - 60,000 miles and are an important maintenance item due to the essential role they play in your engines health, performance and efficiency. Choose Turner Ignition Coils to keep your engine running strong and healthy.

Features and Benefits:

Increased performance
Direct fitment
Signature Turner Blue finish

Through experimentation and data acquired from our E36 World Challenge Touring Cars, it was discovered that in long corners and under heavy braking that there was an oil starvation problem in the M50 and M52 engines. This system was developed to keep oil in the sump and eliminate the starvation problem. After several iterations, further testing and data acquisition in the Touring Cars showed that this system eliminates the problem of oil starvation. This is a less expensive alternative to replacing the stock oil pan with the factory BMW M3 Lightweight oil pan, while still achieving the similar results.

*Requires Professional Welding

Installation instructions (E36/Z3 Oil Pan Baffle for M50, M52, S50, S52 engines)

This item fits the following BMWs:
1992-1999 E36 BMW 323is 323ic 325i 325is 325ic 328i 328is 328ic M3
1992-1995 E34 BMW 525i
1997-1998 E39 BMW 528i
1997-1998 Z3 BMW Z3 2.8
1998-2000 Z3 BMW Z3 M Coupe M Roadster S52

Through experimentation and data acquired from our E36 World Challenge Touring Cars, it was discovered that in long corners and under heavy braking that there was an oil starvation problem in the M50 and M52 engines. This system was developed to keep oil in the sump and eliminate the starvation problem. After several iterations, further testing and data acquisition in the Touring Cars showed that this system eliminates the problem of oil starvation. This is a less expensive alternative to replacing the stock oil pan with the factory BMW M3 Lightweight oil pan, while still achieving the similar results.

*Requires Professional Welding

Installation instructions (E36/Z3 Oil Pan Baffle for M50, M52, S50, S52 engines)

This item fits the following BMWs:
1992-1999 E36 BMW 323is 323ic 325i 325is 325ic 328i 328is 328ic M3
1992-1995 E34 BMW 525i
1997-1998 E39 BMW 528i
1997-1998 Z3 BMW Z3 2.8
1998-2000 Z3 BMW Z3 M Coupe M Roadster S52

BMW E46 M3 Race Alternator Pulley Turner Motorsport

Enhance the performance of your BMW E46 M3 with the BMW E46 M3 Race Alternator Pulley from Turner Motorsport. Engineered for racing enthusiasts, this alternator pulley reduces rotational mass for improved engine response and horsepower gains. Crafted from high-quality materials, it ensures durability and reliability on the track. Upgrade your BMW E46 M3's performance with this premium race alternator pulley.

• Reduces rotational mass for improved engine response
• Increases horsepower gains
• High-quality materials ensure durability and reliability
• Designed for racing enthusiasts

The factory VANOS exhaust hub on the S54 engine is known to develop excessive play where the drive tabs interface with the oil pump disk. Over time, this imprecise fitment causes a back-and-forth rattling motion that can result in the tabs shearing off inside the engine, risking catastrophic damage or complete engine failure. Unlike other aftermarket solutions that require full VANOS disassembly, retiming, or replacement of the oil pump disk, the Turner Motorsport S54 VANOS Hub Upgrade offers a smarter approach. Our bolt-on fix eliminates the common failure point without opening the VANOS unit or disturbing engine timing.

Our solution involves removing the worn tabs from your stock exhaust hub and installing our precision-fit replacement, which is precision-machined from 4340 steel and hardened to meet OEM specifications. Designed using 3D scanning and CAD modeling, the Turner Motorsport VANOS Exhaust Hub Upgrade provides a tight, interference-free fit into the oil pump disc, completely resolving the issue without unnecessary labor.

Features & Benefits:

Direct bolt-on solution for S54 VANOS oil pump drive tab failure, preventing potentially catastrophic damage to engine internals Precision-machined from high-strength 4340 steel and heat-treated to match OEM specifications Designed using 3D scanning and CAD modeling to ensure precise fitment within the OEM oil pump disc Engineered to eliminate the play that exists between the exhaust hub and oil pump disc from factory Backed by extensive real-world testing and our lifetime replacement program!

All vehicles will lose some degree of performance due to heat soak under the right operating conditions.  Engine management systems constantly monitor operating conditions and modifying parameters based on sensor inputs. BMW integrated the intake air temp sensor in the MAF housing on models such as the E39 M5, and, being sandwiched behind a hot radiator and in some applications next to an even hotter valve cover, this is less than ideal for performance applications. Absorbing excess heat from its surroundings, the MAF can’t shed it fast enough, and the ECU reads an inaccurately high intake air temperature. Compensating for this false hot air measurement, the ECU pulls timing and runs a richer fuel mixture, resulting in a significant loss of torque.

What can you do?  Locate an intake air temp sensor in a location where it can properly measure incoming air temps and where it's less prone to heat soak. Mounting the sensor further away from the heat source and isolating it from the MAF housing, it can both resist the effects of heat soak longer and respond to temperature changes more quickly.  The result is you’ll experience reduced torque loss and more consistent power output when you’re pushing your engine hard. 

The Turner engineering team was initially skeptical of the claimed performance benefits of this modification. They first set out validate the functionality and performance benefit of a temp sensor relocation. Replicating stop-and-go traffic heat soak in a 2001 540i was a simple task in a controlled environment - their dynometer. First the car was heat soaked to simulate being stuck in traffic or moving at low speeds by running the car four times on the dyno with the dyno's cooling fans disabled. The fans were then turned on for three more runs to observe the recovery rate once air flow was reintroduced. The test: following this procedure once with a stock IAT, and once with their relocation kit in place. 

The result? Turner recovered 11lb-ft torque at 2500rpm through use of their relocation kit, with even greater recovery to be found for M5 owners. Here are the heat soak-related torque losses Turner experienced:

Stock IAT location:
18rwtq at 2500rpm
10rwtq at 3000rpm
9rwtq at 3700rpm

Turner IAT Relocation:
7rwtq at 2500rpm
5rwtq at 3000rpm
5rwtq at 3700rpm

**Click here for installation instructions**

The Turner engineering team designed a complete plug and play kit (unlike all other options on the market) that makes for quick, easy, and reversible installation. Weather-sealed connectors keep out the elements, while sheathed wiring offers a clean appearance underhood. With a harness nearly 3 feet long - the Turner IAT relocation kit offers flexibility in positioning, but not too long that you're left with unsightly excess wiring. Turner recommends positioning the sensor in a location away from engine heat, but still within the intake ducting to achieve accurate intake temp readings - such as the far side of the base of the airbox. Vehicles with cold air intakes with cone-style filters can even position the sensor in the end of the filter. Simply drill a hole in your (cool) location of choice and plug in the harness. More information including installation instructions and some good examples of sensor mounting locations can be found in our DIY PDF. 

We include everything you need to relocate your IAT, just select your desired sensor brand below - Genuine BMW or original equipment Beru.

Also the perfect plug-n-play option for anyone looking to upgrade their intake to utilize an Alpha-N tune!

Note for vehicles with M62 engine: applicable to 1999 and up

Our B Series ignition coils are designed with performance and efficiency in mind. An engine needs 3 main components to run (Air, Fuel, Spark.) Ignition coils are responsible for 1/3 the operation your engine and it would be smart to weigh the options when shopping. Turner B Series ignition coils are modified to increase energy output; more energy output results in a faster, more efficient and consistent burn to make sure your fuel is being utilized to its maximum potential. Our signature Turner ignition coils feature a blue housing that give your engine the performance and aesthetic your looking for.

Ignition coils should be changed every 40,000 - 60,000 miles and are an important maintenance item due to the essential role they play in your engines health, performance and efficiency. Choose Turner Ignition Coils to keep your engine running strong and healthy.

Features and Benefits:

Increased performance
Direct fitment
Signature Turner Blue finish

When we designed this catch we wanted to have the most function options available, the best separation method, and the easiest to service. The Turner engineered catch cans offer a pre-setup design based ion desired flow direction, however this does not limit you to this flow. The inner baffle orientation can be easily adjusted to flow in both directions in case you decide to move this catch can to a different vehicle. A 4 chamber system  baffle system inside the catch can was engineered to create multiple changes in the direction of airflow within the separator to cause oil droplets to fall out of suspension before exiting the catch can. Having a closed / recirculated design reduces oil ingestion and promotes cleaner emissions and odor-less operation.

Our catch can was also designed with the idea that the cans fill level can easily be checked with a top mounted dipstick and an optional use bottom drain hole. The drain system comes complete with a valve and hose to be mounted at a lower area of the vehicle so when you're doing an oil change you can drain the catch can.

Features:

• 6061-T6 billet machined body, anodized black for lasting protection and appearance
• Strategically positioned 4 chamber baffle system maximizes oil / air separation 
• Knurled and black anodized oil dipstick makes inspecting oil volume of reservoir clean and simple
• Sealed with a pre-installed viton O-Ring
• Includes 2.5mm allen key to remove baffle plates for cleaning
• Engineered to create multiple changes in the direction of airflow within the separator to cause oil droplets to fall out of suspension before exiting the catch can
• Closed / recirculated design reduces oil ingestion and promotes cleaner emissions and odor-less operation
• Optional use drain hole - drain kit included!
• Universal mounting kit

A combination of billet fittings and AN lines for an upgraded and serviceable crankcase vent hose. Attaches between the oil separator and the CSL air box.

The factory rubber/plastic hoses become brittle and crack over time. Brittle and cracked hoses can cause multiple vacuum leaks that are impossible to repair without hose replacement. Vacuum leaks can cause many problems including rough running, missing, stalling at idle, and even a no-start condition. The factory hoses offered through BMW are plastic and will yield the same results of becoming brittle and damaged over time.

We have created a full motorsport style solution with our CSL Crankcase made from machined 6061 billet aluminum with AN style fittings and nylon fiber braided lines. This is a fully serviceable replacement that will outlast every one of the OEM replacements. Our AN crankcase line can be used to replace the factory brittle hose to ensure your S54 is free from vacuum leaks and performing properly.

OEM CSL Vent Hose (11157833649) - Direct Replacement

Key benefits:

Lifetime replacement of the brittle OEM plastic crankcase breather hose
Fully Serviceable
Motorsport Aesthetic to compliment your CSL Intake Plenum
Design:

Fittings are made from billet 6061-T6 aluminum and finished in Type II black anodizing
Pre-anodized machined Turner branding
Nylon fiber braided lines
Fittings are a direct replacement for the plastic OEM fittings

Our B Series ignition coils are designed with performance and efficiency in mind. An engine needs 3 main components to run (Air, Fuel, Spark.) Ignition coils are responsible for 1/3 the operation your engine and it would be smart to weigh the options when shopping. Turner B Series ignition coils are modified to increase energy output; more energy output results in a faster, more efficient and consistent burn to make sure your fuel is being utilized to its maximum potential. Our signature Turner ignition coils feature a blue housing that give your engine the performance and aesthetic your looking for.

Ignition coils should be changed every 40,000 - 60,000 miles and are an important maintenance item due to the essential role they play in your engines health, performance and efficiency. Choose Turner Ignition Coils to keep your engine running strong and healthy.

Features and Benefits:

Increased performance
Direct fitment
Signature Turner Blue finish

Due to weak plastic construction, the factory plastic crankcase ventilation breather hose is known to fail. After years of exposure to piping-hot engine bay temperatures and chemical-laden oil vapors, the corrugated plastic tubing can crack, crumble, or fail altogether.

We set out to bulletproof your N52 CCV system with a durable silicone breather hose, designed to provide a comprehensive upgrade and permanent replacement for the factory plastic hose. By replacing the flimsy, heat-hardened OEM plastic hose with a four-ply fluorosilicone hose, you'll experience peace of mind knowing your N52 is free from the inevitable return of oil leaks, vacuum leaks, and drivability concerns that would have been.

This breather hose is found at the front of the engine, and is used to connect the oil separator to the valve cover. It replaces OEM part number 11157522931.

Features:

Silicone construction ensures a durable replacement that is sure to outlast OE plastic
Designed as a direct replacement for the factory breather hose
Retains heating function and OE electrical connector
Design:

Four-ply wire-reinforced fluorosilicone hose is designed to resist degradation due to exposure to oil vapors
O-rings are pre-installed in OE connectors for a lasting seal
Includes pre-installed zinc-coated hose clamps for durability and corrosion resistance
Product Development:

Our Silicone CCV Hose Upgrade was designed, engineered, tested, and quality inspected by our Research and Development team in our Wadsworth, Ohio, facility. We strive for the highest level of precision and quality through leading-edge product development technology, including FARO laser scanning for reverse engineering and quality inspection, SolidWorks 3D CAD modelling, rapid prototyping utilizing our in-house 3D printer, and rigorous long-term product testing.

If you own an M57-equipped BMW, you already know this twin-turbo diesel powerplant is an absolute torque monster. What you might also know is that all that low-end grunt and high-compression diesel vibration wreaks absolute havoc on your accessory drive system.

From the factory, both the E90 335d and E70 X5 35d utilize a rigid alternator pulley. With each cylinder's fire, the crankshaft experiences a violent micro-acceleration. Because the alternator has a heavy internal rotor spinning at high speeds, it wants to keep spinning at a constant rate. When the engine suddenly slows down (even minutely between firing cycles), the alternator fights the belt. This constant tug-of-war results in extreme stress on your engine's belt-driven components. At best, it’s an annoying, unrefined chirp at idle; at worst, it’s a ticking time bomb for your expensive harmonic balancer.

To solve this issue, many enthusiasts choose to run a clutched alternator pulley (also called an overrunning alternator pulley). A clutched pulley allows the alternator to "freewheel" or coast when the engine slows down, completely isolating its rotational inertia from the belt drive to prevent component wear. While the N52's clutched pulley (12317560483) is a straight bolt-on, the offset is incorrect for the E90 335d's accessory drive. Thankfully, our engineers designed this zinc-coated spacer to provide the precise amount of spacing needed to perfectly align the new pulley with existing belt drive components.

If you own an M57-equipped BMW, you already know this twin-turbo diesel powerplant is an absolute torque monster. What you might also know is that all that low-end grunt and high-compression diesel vibration wreaks absolute havoc on your accessory drive system.

From the factory, both the E90 335d and E70 X5 35d utilize a rigid alternator pulley. With each cylinder's fire, the crankshaft experiences a violent micro-acceleration. Because the alternator has a heavy internal rotor spinning at high speeds, it wants to keep spinning at a constant rate. When the engine suddenly slows down (even minutely between firing cycles), the alternator fights the belt. This constant tug-of-war results in extreme stress on your engine's belt-driven components. At best, it’s an annoying, unrefined chirp at idle; at worst, it’s a ticking time bomb for your expensive harmonic balancer.

To solve this issue, many enthusiasts choose to run a clutched alternator pulley (also called an overrunning alternator pulley). A clutched pulley allows the alternator to "freewheel" or coast when the engine slows down, completely isolating its rotational inertia from the belt drive to prevent component wear. While the N52's clutched pulley (12317560483) is a straight bolt-on, the offset is incorrect for the E70 35d's accessory drive. Thankfully, our engineers designed this zinc-coated spacer to provide the precise amount of spacing needed to perfectly align the new pulley with existing belt drive components.