Flywheels

The factory BMW S55 dual-mass flywheel is engineered with comfort in mind, catering to the luxury-oriented expectations of the brand’s driving experience. Its design focuses on dampening drivetrain vibrations, smoothing out gear transitions, and minimizing harshness during operation. However, this refinement costs valuable performance. The dual-mass flywheel adds a substantial 26.5 lbs of rotational mass to the drivetrain, which significantly hinders throttle response and makes rev-matching feel sluggish and disconnected. Moreover, dual-mass flywheels are notorious for being a weak link in modified or high-performance builds and can prove costly to replace when they inevitably fail.

Our Single-Mass Lightweight Flywheel Conversion addresses all of these shortcomings with a purpose-built, lightweight, single-mass design that prioritizes performance. Weighing in at only 18.5 lbs., this design significantly reduces rotational mass, allowing your S55 to achieve its true motorsport potential!

Features & Benefits:

Precision machined from 4140 HT heat-treated chromoly steel for exceptional toughness, even wear properties, and increased durability.
Material quality promotes even wear across the entire friction surface, prolonging component lifespan.
Heat treated to HRC 28-32, tempered to relieve stress and improve dimensional stability.
Hardness improves component wear characteristics.
Black oxide coated for corrosion resistance on non-friction surfaces.
Precision balanced to exceed OEM specification (G16 spec to 175g-mm).
SFI 1.1 certified to ensure safe operation under extreme operating conditions.
Specifically designed to work with S55 OE-architecture clutches.
Optimized step height maximizes clutch clamp load and offers a prolonged service life.
Performance:

10 lbs. lighter than the factory BMW flywheel!
OEM Dual-Mass: 26.5 lbs.
Turner Motorsport Single-Mass: 18.5 lbs.
Faster revs
Improved throttle response and acceleration
Allows for a more engaging driving experience and delivers a feeling of direct connection
Installation:

Flywheel Hardware: For added peace of mind, apply Blue or Orange Loctite when installing factory flywheel bolts that do not come with pre-applied threadlocker.

Engineered in-house, we designed this lightweight, single-mass flywheel to provide more than 10 pounds of weight savings over the factory flywheel. While some ultra-lightweight performance flywheels are manufactured from aluminum, our designers opted for a more driveable experience with steel. The mass provided by steel helps dampen vibrations and noise, delivering near-factory refinement with most of the benefits of a lightweight flywheel: quicker throttle response, improved durability (and longevity), and more effective transfer of power to the wheels.

Modern flywheels are built with additional components that are designed to dampen and minimize vibrations from the engine and transmission. Weight has increased and reliability has decreased. With additional weight more energy is required for it to move. A lightweight flywheel does away with the dual mass design and its additional mass so more energy can be diverted to where it counts most - moving the car. The flywheel and clutch is one of the first areas that engine builders address when making the rotating assembly lighter for race engines. The dampening effect is just not needed on cars that are focused on performance. And with a single-mass flywheel the unreliable DMF design is eliminated.

When it comes to selecting a clutch to pair with a lightweight flywheel, consider the driving you’ll be doing. As a single mass flywheel eliminates the dual-mass dampening of the factory flywheel, to retain the lowest noise, lowest harshness driving experience possible, select a clutch with a dampened disc such as the ACT Heavy Duty. For dedicated track cars, a solid clutch hub is appropriate.

Our recommendations:

Street: ACT Heavy Duty
Track: ACT Xtreme for high torque cars or OE 335is LuK (with 440lbs-ft or less)
Features:

Precision machined from 4140 HT heat treated chromoly steel for exceptional toughness, even wear properties, and durability.
Material quality promotes even wear across the entire friction surface
Heat treated to HRC 28-32, tempered to relieve stress and improve dimensional stability and elevated temperatures
Hardness improves wear characteristics
Black oxide coated for corrosion resistance on non-friction surfaces.
8620 steel pilot bearing pin, case hardened and Precision ground for maximum wear resistance.
Precision balanced to exceed OEM specification (G16 spec to 175g-mm).
SFI 1.1 tested and certified to ensure safe operation under extreme operating conditions
SFI 1.1 specifies minimum material properties and requires a 3rd party lab certification test, spinning the flywheel to 1.5x redline for 1 hour to ensure the flywheel will not burst.
Specifically designed to work with N54 architecture clutches
Step height designed to optimize clamp load and maximize the usable range of clutch wear for a long service life
Performance:

Turner Flywheel 18.6 lbs
10 lbs lighter than the factory BMW flywheel (Stock Flywheel 28.9 lbs)
Faster revs
Improved throttle response
Improved acceleration
Sportier driving experience
Stock flywheel weight - 28.9lbs
Turner single mass flywheel weight = 18.55lbs

Single Mass Flywheel Conversion:

Audible chatter from the transmission after installation is considered normal. As with most single mass flywheels, there is less dampening in the flywheel to reduce "gear noise." This chatter noise may be more present when the transmission fluid temperatures are hotter and may be intensified by other modifications. Most gearboxes will experience some chatter noise at hotter temperatures. Please be advised that this noise will disappear once the clutch pedal is depressed. This symptom may be lessened by adjusting transmission fluid weight, turning off electrical/driveline consumers (A/C, High Beams, ETC.), and by raising the RPM slightly.

Installation:

Flywheel Hardware: For added peace of mind, apply Blue or Orange Loctite when installing factory flywheel bolts that do not come with pre-applied threadlocker.

This item fits the following BMWs with 8 bolt flywheel and build date up to 01/2009 or earlier:
2008-01/2009 E82 BMW 135i 135is 1M
2007-01/2009 E90 BMW 335i 335xi 335i xDrive - Sedan
2007-01/2009 E92 BMW 335i 335xi 335i xDrive - Coupe
2007-01/2009 E93 BMW 335i - Convertible
2008-01/2009 E60 BMW 535i 535xi 535i xDrive

ARP Flywheel Bolts are a premium grade 8740 alloy that is rated far superior to "aircraft" quality. Each stud is heat-treated, ensuring complete heat penetration, to increase the clamping load up to 200,000 psi. ARP studs are threaded after heat-treat, which gives them 1000% (that's ten times!) better fatigue strength than studs threaded prior to heat-treat. Threading the studs after heat-treating is more difficult and costly (as it's harder on tooling) but the results are well worth the effort. These simply are the best bolts we've found and we highly recommend them in any and all applications. 

ARP is a company that prides itself on performance and durability, no matter the application. Offering the finest engine hardware money can buy is the driving initiative at ARP and this is evidenced by the staggering amount of satisfied customers and race teams the world over.

This item fits the following BMW Engines: 
S14 2.3L