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BMW Differential and Gearing Upgrades

Upgrading various parts of the differential can have tremendous benefits in your car's performance. It's easy to forget that the differential is a source for making your car faster and handle better so it's often overlooked. The engine is not the only place to make the car faster. Our differential options vary from gearing upgrades to limited slip conversions. You can purchase the ring & pinion gear sets on their own (professional installation required) or have us build a diff around your own specifcations. The options are almost endless! Every custom-built diff is fully rebuilt with seals and bearings. We also design and supply bushing options to reduce driveline wind-up, finned differential covers for better cooling, and more!

Ratio Changes - Changing the differential gearing is one of the best and most-effective upgrades you can make on any BMW (old or new). By using a shorter (numerically higher) final drive ratio you are increasing your RPM relative to road speed - this puts you in a more powerful RPM range than before! Since you're in a 'meatier' part of the power band you're now putting down more power/torque to the ground. If you can trade outright top speed for faster acceleration at daily speeds then this is the perfect upgrade for you.

Limited Slip Upgrades - Sadly, many BMWs today are not equipped with a limited slip (posi-traction) differential. BMW has tried to compensate by using traction control that cuts power at the engine or applies the brakes to retard wheel spin (or a combination of both). But nothing beats the function and feel of a a true LSD which may be why BMW continues to use them in M cars. Our LSD upgrades can be done a number of different ways - a factory-type limited slip unit with either 2 or 3 clutch packs, helical type, OS Giken unit, or something truly custom. We can also vary ramp angles and setup to change the limited-slip behavior under acceleration, deceleration, and cornering. Need a custom diff? Call or e-mail to have a quote.

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OS Giken - Corporate Logo
T#:200230
Part#: MN024-HA
In Stock
$ 1,650.00 USD
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$ 1,650.00 USD
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If your MINI is only for competition use - autocross, time trial, or racing - this OS Giken LSD may be a better option than the standard 1.5-way unit. This race-spec LSD was developed over several seasons of competitive autocross. It uses a new high pressure ring for quicker response time and faster lockup. This makes it ideal for quick transitions and rapid on/off throttle motions typically encountered on the track. It's a one-way lockup so the car stays predictable under braking and gives the driver more feedback. For street use we prefer the normal 1.5-way setup because it's more progressive during lockup.

The biggest shortcoming of any MINI is not the lack of power - it's being able to put all of its useable power to the ground! The Cooper S is basically a one-wheel drive car and sending 200+ hp through that one tire does not live up to its full potential. A limited-slip differential is essential to any highly-tuned FWD car. The OS Giken Super-Lock is one of the most advanced clutch-type differentials on the market, and a favorite of autocrossers and road racers. The OS LSD for the MINI features ten clutch discs for a smooth and progressive lockup. By putting all of your available power to the ground you're at an instant advantage over the stock open-type differential. You'll be able to power through corners and on rough surfaces instead of uselessly spinning a wheel. Understeer is reduced by giving more bite to the tire that has the most traction. With an LSD in your MINI Cooper S you'll wonder why it wasn't first on your list to begin with (or why MINI/BMW left it out in the first place...).

The MNI OS Giken LSD uses a special 80W250 fluid that must be purchased separately.

This item fits the following BMWs:
2002-2006 R53 MINI MINI Cooper S (6MT manual transmission only)
2007-2013 R56 MINI MINI Cooper S (6MT manual transmission only)
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OS Giken - Corporate Logo
T#:34382136
Part#: BM237HAKT
Ships in 2 Business Days
$ 2,100.00 USD
Free Shipping on orders $49 and up
Upgrade to a better performing LSD, includes tune.
OS Giken - Corporate Logo
T#:1387
Part#: BM237-HA
Ships in 2 Business Days
$ 1,950.00 USD
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$ 1,950.00 USD
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The M Dynamic limited slip unit on the M3 is designed to be a pure street car differential. It's simply not up to the rigors of professional or amateur racing. The OS Giken Super Lock LSD is giant step up in from a stock M3 lsd unit. It's ready for the extreme conditions of racing, offers 100% progressive locking capability, and is able to do this while operating smoothly and quietly. It's use of advanced technologies that make it perfect for both street cars AND pro race cars... and everything in between. We're excited to be carrying the OS Giken LSD unit in our performance catalog, as we've been using them in our own Championship winning M3 race cars.

OS Giken incorporated revolutionary new ideas when developing the their own limited slip diff, utilizing their accumulated racing knowledge and experience and over 4 years of development. Their design uses an unprecedented number of friction plates (up to 28 total!) for better locking force, better engagement/disengagement, and less generated heat. The end result of their efforts is the OS Giken's OS Super Lock LSD which offers incredible durability and reliability on street and track driven BMWs. The use of highest quality materials, precise machining, forged gears and sound engineering makes this LSD durable and reliable enough for road racing performance (which we can personally vouch for!). This is such a great design, in that it can be used in any situation -- whether it's for a street car, or a 100% Professional race car. Zero break-in required. Super smooth and quiet engagement, and 100% progressive locking capability. Professional installation is recommended.

This Limited Slip Differential Unit fits the following BMWs:
2001-2006 E46 M3 coupe & convertible
2008-2013 E9X M3 coupe & convertible
1991-1995 E34 M5 sedan
1999-2003 E39 M5 sedan
2006-2008 E85 Z4M Z4 M Coupe, Z4 M Roadster
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IRP - Individual Racing Parts - Corporate Logo
T#:587016
Part#: IRPDB-9XMAL
Special Order: No Guaranteed ETA
$ 133.99 USD
Free Shipping
$ 133.99 USD
Free Shipping
These aluminum mounts are a direct replacement for the stock rubber bushings and have been lightened to remove excess weight. Using aluminum instead of rubber eliminates the "wind up" inherent in rubber mounts, and this deflection slows suspension & drivetrain response. The tradeoff is an increase in NVH. Features: Stiffens chassis/Improves stability Less wear of other components Better durability Provides better control of chassis geometry Replaces OE: 33312284019, 33312283384 Recommended for racing use only Includes: 1 rear aluminum bushing 2 front aluminum bushings
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OS Giken - Corporate Logo
T#:34382134
Part#: LSD-TUNE
Ships in 2 Business Days
$ 150.00 USD
Free Shipping
$ 150.00 USD
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IRP - Individual Racing Parts - Corporate Logo
T#:587020
Part#: IRPDB-46MAL
Special Order: No Guaranteed ETA
$ 151.99 USD
Free Shipping
$ 151.99 USD
Free Shipping
These aluminum mounts are a direct replacement for the stock rubber bushings and have been lightened to remove excess weight. Using aluminum instead of rubber eliminates the "wind up" inherent in rubber mounts, and this deflection slows suspension & drivetrain response. The tradeoff is an increase in NVH. Features: Stiffens chassis/Improves stability Less wear of other components Better durability Provides better control of chassis geometry Replaces OE: 33172282484 Recommended for racing use only Includes: 2 rear aluminum bushing 1 front aluminum bushings
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Enthusiast Bundles - Corporate Logo
T#:37419758
Part#: 049424LAEBKT
Ships in 1-2 days
Sale - Save 17% $ 1,381.99

This product was last offered at the strikethrough price on
05-05-2026

$ 1,149.99 USD
Free Shipping on orders $49 and up
Sale - Save 17%
$ 1,381.99

This product was last offered at the strikethrough price on
05-05-2026

$ 1,149.99 USD
Free Shipping on orders $49 and up

E36 188mm Reinforced Billet Aluminum Differential Cover

Engineered from high-quality 6061 billet aluminum, this differential cover is built for resilience and designed for performance. Hard-coat anodized for a sleek finish and superior corrosion resistance, it not only looks great but also brings functional improvements in strength and cooling. Turner Motorsport has added reinforced mounting ears to withstand the toughest driving conditions—preventing the breakages common with OEM covers.

This cover doesn’t just endure—it performs. The cover features strategically placed external fins on the rear face, base, and mounting ears to efficiently dissipate heat, keeping temperatures stable for optimal fluid longevity and differential health. Inside, the design promotes consistent oiling of the ring gear, reducing wear by ensuring critical cooling and lubrication. An integrated baffle keeps pressure stable and minimizes cavitation.

Compatibility is at the core of the design: it’s compatible with OEM gaskets or RTV, and it retains the factory bushing geometry for easy integration with rubber, poly, and even solid mounts. The upgraded -6AN drain and fill plugs allow expansion for an external oil cooler, ideal for high-performance applications. Plus, a 1/8 NPT port allows for real-time monitoring of differential fluid temperatures.

Key Benefits:

Reinforced mounting ears for robust support—no more broken ears during aggressive driving or track days Optimized cooling with fins on rear face, base, and mounting ears Removable air duct to direct airflow across fins for maximum temperature control Improved internal design to maintain consistent lubrication on the ring gear -6AN ports for external cooler compatibility, increasing fluid capacity and extending change intervals 1/8 NPT port for temperature sensor integration to monitor fluid heat Design Highlights:

Precision-milled from 6061 billet aluminum with a T6 hard-coat anodized finish Fits E36 medium case 188mm differentials Compatible with differential coolers (-6AN) and temperature sensors (1/8 NPT) Works with OEM speed sensor, OEM gasket, and oversized sway bars Designed for easy maintenance with a removable air duct and accessible drain/fill plug ECS Tuning E36 Polyurethane Transmission Mount Set – Street

The ECS Polyurethane Transmission Mounts in this kit provide a solid connection between transmission and chassis, enhancing stability and reducing unwanted drivetrain movement. Built for durability, these mounts feature polyurethane with a 70A durometer for a perfect balance of comfort and performance. Compared to OEM rubber mounts, polyurethane provides less deflection, better power transfer, and much longer life under stress.

Polyurethane’s natural resistance to water, oil, and wear ensures these mounts maintain shape and performance even under heavy compression, making them ideal for spirited driving and track use. The mounts include a mechanical interlock for secure, reliable performance—even under high-torque, forced-induction scenarios. For those seeking a more aggressive setup, ECS also offers an 80A durometer Race mount.

Key Features:

Reduces transmission movement, minimizing mis-shifts and over-revs High-quality polyurethane bonded to 304 Stainless Steel Engaging driving experience with enhanced feedback and control Available in Street (70A) and Race (80A) applications for tailored performance Enjoy smoother shifts, firmer power delivery, and a more engaging drive with the ECS Polyurethane Transmission Mounts.

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