Harness unused potential. Drive with confidence. Engineered to maximize strength and cooling performance while utilizing the unused secondary factory differential mount for enhanced support and driveline stability.

Our Turner Motorsport Dual-Mount Differential Cover is purpose-built to reinforce one of the most critical components in the G8X M3/M4 drivetrain. From the factory, BMW includes a secondary bushing location in the rear subframe but leaves it unused. Our solution fully capitalizes on this overlooked feature, giving the differential a second point of support for improved rigidity, reduced movement, and enhanced driveline response under load.

This cover is more than just a mounting upgrade. It’s precision-machined from 6061-T6 billet aluminum for exceptional strength without unnecessary weight. An aggressive fin profile improves thermal efficiency, helping to lower fluid temperatures in high-stress environments. Inside, the cover features an embossed channel that mirrors the ring gear path, ensuring fluid stays in contact where it's needed most, improving cooling and lubrication in all conditions.

Whether you're carving corners on the street or pushing the limits on track, this differential cover is designed to keep your rear end cool, stable, and responsive.

Key Features and Benefits:

The dual-mount design utilizes the factory-provided secondary bushing location, adding critical support to reduce differential deflection, extend bushing life, and minimize wheel hop.
CNC-machined from 6061-T6 billet aluminum, offering high strength and a precise fit.
Built-in cooling fins increase surface area for improved heat dissipation and lower differential fluid temperatures.
Internally contoured to follow the ring gear profile, promoting consistent fluid coverage and effective lubrication.
Maintains a 1.1-liter fluid capacity, closely matching OEM specifications for ease of servicing.
Integrated -6 AN ports support the addition of an external differential cooler for increased fluid volume and extended service intervals.
Compatible with the factory differential fluid temperature sensor and includes provisions for 1/4” NPT aftermarket sensors.
Product Development:

Like all Turner Motorsport performance solutions, this differential cover was developed in-house by our dedicated Research and Development team. Designed, engineered, tested, and quality-inspected using advanced tools including FARO laser scanning for reverse engineering, SolidWorks 3D CAD modeling, in-house rapid prototyping, and extensive long-term testing, you can trust that this part meets the highest standards of fit, function, and durability.

From spirited street driving to full-throttle track days, the Turner Motorsport Dual-Mount Differential Cover ensures your G8X delivers the response, strength, and cooling capacity it needs when it matters most.

Single piece 6061 construction, optimized cooling, provisions for temp sensor, and external cooler with removable air duct.

Built to last, made from a single piece of 6061 billet aluminum with a rugged and good-looking hard-coat anodizing our diff cover can handle anything you throw at it. Not only is it an absolute masterpiece to look at but the billet diff cover checks all the boxes for features needed. Reinforced mounting ears for strength and stability, never again will you break an ear off your diff cover like the factory units are known to do. Each ear is not only unified with the one-piece billet cover but also feature added material for the highest durability possible. This diff cover is cool, literally, the entire construction was designed with optimized cooling in mind. External fins are strategically placed on the rear face, bottom, and between the mounting ears of the cover, serving as effective heat sinks for optimal heat dissipation. This ensures stable temperatures, promoting longevity for both the fluid and your differential. Additionally, the internal design ensures continuous oiling and lubrication to the ring gear, maintaining its stability and preventing fatigue by controlling heat more effectively. An internal baffle at the cover's corner helps maintain proper pressure and prevents cavitation.

All of the OEM features were retained along with the upgrades. The mounting surface was designed to be compatible with both the OEM gasket or RTV of your choosing, some people don't trust the gaskets and we get it. You can transfer your speed sensor directly to your upgraded billet cover and it even features a provision for the sensor wire mounting. Factory bushing geometry allows you to use any E36 diff busing including rubber, poly, and even solid mounts. The drain and fill plugs on the diff cover are upgraded to -6AN using the provided high-pressure fittings with replaceable o-rings. The drain and fill plugs can now also be used for expanding to an external oil cooler allowing you to further expand the fluid capacity for optimized cooling and service intervals. To keep an eye on things from the driver seat is 1/8 NPT provision for temp sensors, this product from Turner has you covered at every turn.

Why the upgrade?

If you're new to differential covers used in earlier generations like the E30, you'll find significant improvements in the OEM E36 cover. Unlike the E30's single mount design, the E36 features a dual mount design, which was introduced to address common issues such as broken mounts due to worn-out bushings and aggressive driving. This upgrade significantly enhanced durability and reliability.

While the factory E36 differential cover was a significant improvement with its dual mounts compared to the previous generation, there are still some shortcomings that the original cover doesn't address. Most factory differential covers, including those on the E36, are cast from aluminum. However, due to the porous nature of cast aluminum, the mounting ears on these covers cannot withstand the intense shocks typical in motorsport or in vehicles with significantly increased power.

Upgrading to our Reinforced Billet Differential cover gives you the strength you need to push your car to its limits without worrying about snapping a diff mount from clutch kicking or other shocks to the drivetrain. In addition to its enhanced strength, this differential cover includes numerous other upgrades and conveniences. These include improved cooling and lubrication for the ring gear, upgraded fill and drain plugs, and the option to expand an external oil cooler for extreme motorsport usage. Designed to complement both upgraded daily drivers and extensively modified track cars, it also boasts a visually appealing design.

Key Benefits:

Reinforced mounting ears for strength and stability - never again will you break an ear off during an aggressive drive or track event
External fins on the back side, bottom, and mounting ears on the casing for maximum cooling and consistent fluid temps
Removeable air duct to direct air across the cooling fins for even more temperature control
Optimized internal design to keep fluid consistently on the ring gear
Integrated breather to prevent cavitation by venting the appropriate amount of pressure being built up in the diff housing
-6AN ports to incorporate the use of a differential cooler - this increases capacity and lowers temps allowing for extended fluid change intervals
1/8 NPT fitting for the use of a temp sensor to monitor fluid temperature
Design:

Single piece 6061 Billet aluminum construction
T6 Black hard coat anodizing for superior corrosion resistance and aesthetics
Compatible with most differential coolers(-6AN) and temp sensors(1/8 NPT)
Designed to accommodate oversized rear sway bars
Retains OEM mounting features including the use of the OEM gasket
Factory geometry bushing size for use with OEM and aftermarket poly bushings
Removeable air duct for easy access to sensors and drain/fill plug
Retains OEM speed sensor and wire mount location
Product development:

Our Reinforced Billet Diff Cover was designed, engineered, tested, and quality inspected by our Research and Development team at Turner. Nothing but 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 modeling, rapid prototyping utilizing our in-house 3D printer, and rigorous long-term product testing.

Single piece 6061 construction, optimized cooling, provisions for temp sensor, and external cooler with removable air duct.

Built to last, made from a single piece of 6061 billet aluminum with a rugged and good-looking hard-coat anodizing the Turner diff cover can handle anything you throw at it. Not only is it an absolute masterpiece, but this billet diff cover checks all the boxes for features needed. Reinforced mounting ear for strength and stability. The mounting ear is unified with the one-piece billet cover and features added material for the highest durability possible. This diff cover is cool, literally, the entire construction was designed with optimized cooling in mind. External fins are strategically placed on the rear face, bottom, and between the mounting ears of the cover, serving as effective heat sinks for optimal heat dissipation. This ensures stable temperatures, promoting longevity for both the fluid and your differential. Additionally, the internal design ensures continuous oiling and lubrication of the ring gear, maintaining its stability and preventing fatigue by controlling heat more effectively. An internal baffle at the cover's corner helps maintain proper pressure and prevents cavitation.

All of the OEM features were retained along with the upgrades. The drain and fill plugs on the diff cover are upgraded to -6AN using the provided high-pressure fittings with replaceable o-rings. The drain and fill plugs can now be used for an external oil cooler allowing you to further expand the fluid capacity for optimized cooling and service intervals. To keep an eye on things from the driver seat is 1/8 NPT provision for temp sensors, this product from Turner has you covered at every turn.

Upgrading to our Turner Billet Differential cover gives you the strength you need to push your car to its limits without worrying about snapping a diff mount from clutch kicking or other shocks to the drivetrain. In addition to its enhanced strength, this differential cover includes numerous other upgrades and conveniences. These include improved cooling and lubrication for the ring gear, upgraded fill and drain plugs, and the option to expand an external oil cooler for extreme motorsport usage. Designed to complement both upgraded daily drivers and extensively modified track cars, it also offers a visually appealing design.

Key Benefits:

Reinforced mounting ear for strength and stability 16% Increased fluid capacity External fins on the back side, bottom, and mounting ear on the casing for maximum cooling and consistent fluid temps Removeable air duct to direct air across the cooling fins for even more temperature control Optimized internal design to keep fluid consistently on the ring gear Integrated breather to prevent cavitation by venting the appropriate amount of pressure being built up in the diff housing -6AN ports to incorporate the use of a differential cooler - this increases capacity and lowers temps allowing for extended fluid change intervals 1/8 NPT fitting for the use of a temp sensor to monitor fluid temperature Design:

Fits manual transmission Large Case 215mm differentials Single piece 6061 Billet aluminum construction T6 Black hard coat anodizing for superior corrosion resistance and aesthetics Compatible with most differential coolers(-6AN) and temp sensors(1/8 NPT) Designed to accommodate oversized rear sway bars Retains OEM mounting features Factory geometry bushing size for use with OEM and aftermarket poly bushings Removeable air duct for easy access to sensors and drain/fill plug

Single piece 6061 construction, optimized cooling, provisions for temp sensor, and external cooler with removable air duct.

Built to last, made from a single piece of 6061 billet aluminum with a rugged and good-looking hard-coat anodizing the Turner diff cover can handle anything you throw at it. Not only is it an absolute masterpiece, but this billet diff cover checks all the boxes for features needed. Reinforced mounting ear for strength and stability. The mounting ear is unified with the one-piece billet cover and features added material for the highest durability possible. This diff cover is cool, literally, the entire construction was designed with optimized cooling in mind. External fins are strategically placed on the rear face, bottom, and between the mounting ears of the cover, serving as effective heat sinks for optimal heat dissipation. This ensures stable temperatures, promoting longevity for both the fluid and your differential. Additionally, the internal design ensures continuous oiling and lubrication of the ring gear, maintaining its stability and preventing fatigue by controlling heat more effectively. An internal baffle at the cover's corner helps maintain proper pressure and prevents cavitation.

All of the OEM features were retained along with the upgrades. The drain and fill plugs on the diff cover are upgraded to -6AN using the provided high-pressure fittings with replaceable o-rings. The drain and fill plugs can now be used for an external oil cooler allowing you to further expand the fluid capacity for optimized cooling and service intervals. To keep an eye on things from the driver seat is 1/8 NPT provision for temp sensors, this product from Turner has you covered at every turn.

Upgrading to our Turner Billet Differential cover gives you the strength you need to push your car to its limits without worrying about snapping a diff mount from clutch kicking or other shocks to the drivetrain. In addition to its enhanced strength, this differential cover includes numerous other upgrades and conveniences. These include improved cooling and lubrication for the ring gear, upgraded fill and drain plugs, and the option to expand an external oil cooler for extreme motorsport usage. Designed to complement both upgraded daily drivers and extensively modified track cars, it also offers a visually appealing design.

Key Benefits:

Reinforced mounting ear for strength and stability
16% Increased fluid capacity
External fins on the back side, bottom, and mounting ear on the casing for maximum cooling and consistent fluid temps
Removeable air duct to direct air across the cooling fins for even more temperature control
Optimized internal design to keep fluid consistently on the ring gear
Integrated breather to prevent cavitation by venting the appropriate amount of pressure being built up in the diff housing
-6AN ports to incorporate the use of a differential cooler - this increases capacity and lowers temps allowing for extended fluid change intervals
1/8 NPT fitting for the use of a temp sensor to monitor fluid temperature
Design:

Fits manual transmission Large Case 215mm differentials
Single piece 6061 Billet aluminum construction
T6 Black hard coat anodizing for superior corrosion resistance and aesthetics
Compatible with most differential coolers(-6AN) and temp sensors(1/8 NPT)
Designed to accommodate oversized rear sway bars
Retains OEM mounting features
Factory geometry bushing size for use with OEM and aftermarket poly bushings
Removeable air duct for easy access to sensors and drain/fill plug

Streamline the setup process for your Limited Slip Differential (LSD) with this mandatory back-lash setting tool. This custom-designed tool is instrumental in reducing installation time by a whopping 50%! It's important to note that this tool is not part of BMW's offerings. Should there be any defects or warranty-related matters, it's advisable to directly reach out to Team M Factory for prompt resolution.

Gain a significant competitive edge with the MFactory Helical Limited Slip Differential, available at Turner Motorsport. This Helical LSD delivers a smooth and consistent distribution of power to your BMW's wheels, optimizing traction on the street, strip, or track. It's an essential addition for any BMW enthusiast.

Curious about the LSD's role? Without it, your car effectively becomes a one-wheel-drive vehicle, supplying torque to the wheel with less grip. The Helical LSD changes the game by allowing both wheels to receive power while limiting the speed difference between them, in contrast to open differentials commonly found in most vehicles.

Key Features:

• 30-Day Feel the Torque™ Money Back Guarantee: An industry-first assurance that lets you experience the difference. Plus, it's backed by a Limited-Lifetime Warranty for your peace of mind.
• Forged and Cryo-Tempered: Engineered for extreme durability and longevity, ensuring it can withstand the rigors of competition-level drag racing.
• Advanced Shot Peening Technology: Enhances surface hardness, making it well-equipped to handle the shocks of competition-level drag racing.
• Maintenance-Free Gears: Bid farewell to special fluids or rebuilds associated with typical plate LSDs. It's designed for hassle-free ownership.
• Lock-Free Operation: Ensures there's no adverse impact on steering response.

Break-In Procedure: For optimal performance, it's recommended to change the fluid after the first 3-400 miles of use.

Please note that any defects or warranty claims should be directed to Team MFactory.

When it comes to gaining a significant advantage over your competitors, the MFactory Helical Limited Slip Differential (LSD) is your ultimate ally. This LSD offers a seamless and consistent distribution of power to your vehicle's wheels, allowing you to harness maximum traction and put the power firmly on the ground.

But what does an LSD do, you ask? Well, without an LSD, your car essentially operates as a "1-wheel drive," as it can't deliver torque to both wheels simultaneously. Instead, it directs torque to the wheel with less grip, highlighting the limitations of an open differential, which is standard in most vehicles.

An LSD, on the other hand, permits the wheels to spin at slightly different speeds by a limited amount, typically represented as a percentage difference. It's when the differential locks that both wheels receive power. It's important to note that LSDs function differently from locked differentials, such as those in off-road trucks, which supply equal torque and rotational speed to both rear wheels simultaneously, often causing handling issues.

Key Features:

• Crafted from imported Japanese SAE 4320 Steel
• Industry-first 30-day "Feel the Torque™" money-back guarantee, along with a Limited-Lifetime Warranty
• Forged, double tempered, and super sub-zero treated for unparalleled toughness
• Utilizes advanced Shot Peening technology to increase surface hardness
• Engineered to withstand the extreme shock loads of competition-level drag racing
• Advanced gear geometry designed using industry-leading software, delivering more power to the ground
• Exclusively uses the highest quality Brighton-Best Hardware
• Maintenance-free gears eliminate the need for special fluids and rebuilds associated with plate-type LSDs
• Ensures lock-free operation, preventing adverse effects on steering response
• Rated for up to ~1000 WHp

As part of the break-in procedure, we recommend changing the fluid after the first 3-400 miles of use.

Warranty:

MFactory Competition Products stands behind the quality of its Helical LSDs. A limited lifetime warranty is provided, ensuring that these LSDs are free of defects in materials and workmanship upon receipt of the product and professional installation. Any part returned must be determined by MFactory Competition Products to be defective before any warranty credit or replacement is issued.

MFactory Competition Products's obligation under the warranty is limited to repairing or replacing, at its discretion, any part proven defective. The customer is responsible for prepaying transportation charges.

It's important to note that the final determination of the suitability of the products for the intended use is the sole responsibility of the buyer. MFactory Competition Products shall not be liable for any special, direct, indirect, incidental, or consequential damages, including claims for delay, loss of profits, or labor that might be claimed as a result of the failure of any part.

Furthermore, MFactory Competition Products shall not be liable for any damage or injury to persons or property resulting from improper installation or misuse of any part covered by this warranty.

Please be aware that there are no other warranties, whether expressed or implied, extending beyond those set forth above.

Note: To ensure a proper fit, you'll need to reuse the old bearings or acquire new bearings and press them onto each end.

Upgrade your BMW's drivetrain with this comprehensive kit that includes a new pumpkin for a hassle-free bolt-in replacement. Plus, enjoy the added benefit of a $500 refundable core charge. For any defects or warranty claims, please directly reach out to Team M Factory.

The best way to gain a prominent advantage over the competition is to do it with the MFactory Helical Limited Slip Differential. The smooth consistent distribution of power to the wheels with the MFactory Helical LSD puts the power-to-the-ground and maximizes your vehicle's traction. A must for any car be it street, strip, or track.

What exactly does an LSD do you ask? Without an LSD your car is actually 1 wheel drive, in that it can't supply torque to both wheels at the same time and will only supply torque to the wheel with less grip, which is what the shortfall is to an open differential (what most vehicles have).

An LSD only lets the wheels spin at different speeds by a limited amount (typically this is a percentage difference) which is when the differential locks and both wheels get power. This is not how locked differentials work such as in off-road trucks which supply equal torque and rotational speed to both rear wheels at the same time, which can cause issues with handling.

Features:

An industry first, 30-day Feel the Torque™ money back guarantee and a Limited-Lifetime Warranty!
Forged and Cryo-tempered
Advanced Shot Peening technology for increased surface hardness
Designed to withstand the extreme shock loads of competition-level drag racing
Maintenance-free gears eliminate the need for special fluid or rebuilds associated with typical plate LSDs.
Lock-free operation ensures no adverse steering response.
**As a break-in procedure, we recommend changing the fluid after the first 3-400 miles of use.**

Includes $500 core charge to be refunded when we receive your rebuildable core.

The Powerflex Rear Diff Mount Bushing for the BMW E21 offers a robust solution to support and stabilize the differential, replacing the standard rubber bushings with durable polyurethane. This upgrade minimizes unwanted differential movement, enhancing driving dynamics and responsiveness.

Key Benefits:

1. Enhanced Stability: By minimizing differential movement, Powerflex bushings ensure consistent alignment, giving better rear-end stability.
2. Improved Longevity: Unlike rubber, polyurethane is resistant to aging and degradation from elements like oil and road debris.
3. Responsive Handling: With reduced play in the differential mount, power transfer becomes more direct, allowing for sharper throttle response.
4. Vibration Dampening Options: Powerflex offers options like the Black Series for motorsport applications and the standard Purple for everyday performance with minimal increase in vibration.

These bushings are popular among E21 owners who want a durable, performance-oriented solution that balances comfort and handling precision. Ideal for both spirited driving and daily use.