BMW E30 Heavy Duty Dual Mount Differential Cover

Designed for track drivers, drift enthusiasts, and drag racers alike, this all-in-one driveline upgrade eliminates the factory weak points and reinforces your drivetrain for high-performance abuse. Whether you're laying down 500HP, clutch-kicking through corners, or launching hard at the strip, this cover keeps your differential secure, cool, and ready for battle.

The stock E30 differential cover features a single mounting provision—fine for a stock M20, but guaranteed to fail on your boosted high-horsepower M5X build. After years of broken covers, mounting tabs, and dreams, our team of E30 enthusiasts engineered the ultimate fix.

Unlike the brittle OEM cast aluminum cover, our upgraded differential cover is CNC-machined from 6061-T6 billet aluminum, offering a 30% increase in material strength alone. More importantly, a secondary mounting ear has been integrated into the design for added support, drastically improving stability and driveline shock absorption. The secondary mount is tied into the chassis using a reinforced sheet metal bracket and a billet aluminum plate, allowing for bolt-on installation or welding for ultimate rigidity.

Another major flaw of the factory E30 differential cover is its lack of any cooling provisions, leading to overheated fluid and premature wear. Our engineers solved this issue by incorporating advanced cooling features into the design. Large external fins have been added to the cover, and are optimized using CFD (Computational Fluid Dynamics) analysis to efficiently dissipate heat, reducing overall fluid temperatures. By maintaining a more stable differential temperature, this cover ensures consistent performance and extends the lifespan of your differential fluid. A built-in air duct assists in cooling by increasing airflow around the differential, further preventing heat-related failures. Our cover features optional -6AN fittings, allowing for easy integration of an external fluid cooler if desired. Finally, a 1/8 NPT port is included with the kit to ensure compatibility with fluid temperature monitoring systems.

Precision-machined from 6061-T6 billet aluminum and finished with a black hard coat anodizing, this cover is built to withstand hard use. Despite its robust construction and superior durability, this differential cover retains factory mounting features. This means any E30 188mm differential cover bushing can be installed, allowing you to tailor our upgraded cover to your build. The cover also accommodates large rear sway bars, ensuring fitment on cars with upgraded suspension. Our proprietary removable air duct provides easy access to sensor bungs, fill plugs, and drain plugs, making differential service a breeze.

FEATURES

Unmatched Strength & Durability - Heavily reinforced mounting locations are designed to withstand extreme horsepower, torque, and shock load. Secondary Differential Mount - A built-in secondary mount, integral sheet metal bracket, and billet adapter plate make this the strongest E30 differential cover on the market. Bolt-On or Weld-On Installation - The secondary mount is designed for easy bolt-in installation or can be welded to the chassis for ultimate rigidity. Optimized Cooling - Large external fins, designed using CFD analysis, dissipate heat efficiently, reducing overall differential fluid temperatures. Integrated Breather System - An integrated breather system reduces internal cavitation by properly venting built-up pressure. Enhanced Fluid Management - Includes a 1/8 NPT sensor port for real-time fluid temperature monitoring, and optional -6AN fittings for adding an external fluid cooler. Aerodynamic Air Duct - The included aerodynamic air duct further reduces fluid temperatures, increasing fluid service life and reliability. KIT CONTENTS

Dual Mount Differential Cover Assembly Includes the cover, sheet metal mounting bracket, billet aluminum mounting plate, and aerodynamic air duct. Installation Hardware Kit Includes everything you need to install this masterpiece on your E30! Differential Gasket Choose between a Genuine BMW paper gasket or make your own gasket with Loctite 5970. Optional -6AN fittings (2) for adding an external fluid cooler. Differential Cover Bushings Choose between Powerflex, OE MOOG, and Genuine BMW, or add your own (two E30 188mm differential cover bushings required for installation). Gear Oil Choose between Liqui Moly, Redline, and Genuine BMW, or supply your own fluid for reassembly.

Lightweight single mass flywheel paired with the Sachs clutch kit, perfect for naturally aspirated M20's! Fits early and late model cars.

A perfect upgrade and refreshment for your M20! Free up lost horsepower with the lightened single mass flywheel and get back the life in your clutch pedal. This kit is put together with the idea of an OEM+ upgrade, perfect for people looking to refresh the driving experience of their M20 and get back the full potential of this tried and true motor.

This kit includes everything you need to do the clutch and flywheel service on your M20. While you're in there it is a good idea also to purchase the common transmission seals, fluid, and mounting hardware which are listed below.

Clutch Kit:

Sachs OE replacement clutch disc - 21211223097
Sachs pressure plate - 21211223026
Sachs 323 throw-out bearing (taller bell housing/ETA models) - 21511204525
Pilot bearing - 11211720310
Turner Single-Mass Flywheel:

Lightweight flywheel for quicker, effortless revs that improve throttle response and free up lost horsepower. Tested and approved by the engineering team at Turner Motorsport, tested in early, late, ETA and IS model E30s for confirmed fitment.
Fits shallow and deep bell housing transmissions
Ring gear suited for both starters (P# 12411726504 + 12411361874)
Heavier than other lightweight flywheels, and lighter than OEM, it's like the Goldie Locks of flywheels - it's just right
Reference pin for bell housing crank sensor
Strong Single-Piece 4140 HT Steel construction
Designed to be used with factory and OE clutches
Weight savings between 5-14lbs depending on your OE flywheel

Components strongly suggested while your transmission is out of the car.:

Transmission Seals Kit - T#29898446
Fluid - 75-90 or preferred fluid type (approximately 1.25 liters)
Transmission Mounting hardware - T#30197962

The ULTIMATE shifter upgrade for your BMW! Experience more precise throws, less shift lever travel, and an all-around transformation in your shifting experience.

For dozens of years, enthusiasts have critiqued the imprecise and vague feeling of BMW manual transmissions. Plagued with long throws, fore and aft play in gear, and a generally loose feeling, your OEM BMW shifter leaves much to be desired. While most standard carrier-mount short throw shifter kits will aid in reducing throw length and eliminating side-to-side play in gear, some enthusiasts long for a hardcore, race-inspired shifter that completely removes play and excessive throw length. At Turner Motorsport we share the same desire and set out to offer the ULTIMATE upgrade with this Performance Chassis Mount Short Shifter.

WHY UPGRADE?

Factory BMW shifter assemblies are complex by nature. The main component of this assembly is the shift carrier, a cast aluminum piece positioned inside the transmission tunnel that incorporates bushings at both ends for mounting. Like most factory parts, these bushings are designed to reduce NVH (noise, vibration, and harshness) transmission to the cabin. To the spirited driver, however, these bushings translate to flex and vagueness in the shift lever. Moreover, because this carrier is mounted to both the transmission and the body, the entire shifter assembly will "float" with the driveline, further increasing the vague and imprecise feeling of your shifter.

Our Performance Chassis Mount Short Shifter removes the shift carrier assembly entirely—removing any prospect of flex caused by bushings or driveline movement. By contrast, this chassis mount shifter offers a drastic reduction in shift lever travel, vagueness, and side-to-side play. An elevated base allows for moving the fulcrum point upwards, resulting in a much shorter and more precise throw. Shift times are further reduced by a tall, "rally style" shift lever, used to aid in leverage while also bringing the lever closer to the steering wheel. Our design incorporates a proprietary centering spring design, which is adjustable for increasing or decreasing self-centering force. In short, this design eliminates all the drawbacks of your factory BMW shifter, translating to more control, greater precision, shorter throws, and faster shift times.

FEATURES & BENEFITS

Reduced Throw: Modified shifter geometry and heightened fulcrum point translate to a shorter shift lever throw
Improved Shifter Feel: Eliminating the shift carrier and associated bushings drastically reduces "slop" and side-to-side play in the shift lever
Increased Precision: Mounting the shifter to the chassis allows for little to no variation in gear selection
Universal Fitment: Fits many BMW chassis with the provided base plate and hardware (see "Fits These Cars" for exact fitment information)
DESIGN

6061 aluminum, 4130 steel, and 316 stainless steel construction
A type-II black anodized finish
Adjustable self-centering spring
"Rally Style" shift lever
Spherical bearing pivot with maintenance-free brass insert
Product Development:

Our Chassis Mount Shifters are 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.

Vague or slopping shifter feel even after installing a short shifter or new OE shifter linkage bushings?  Looking for a more precise shifter feel in your classic BMW?  Consider replacing your old, worn rubber rear shifter bushing with new Turner poly to get the best shifting experience possible!  The Turner engineering team wasn’t satisfied with the other options on the market, so we set out to design the best solution for ease of installation and performance.

The competition requires the installer to cut or burn the rubber bushing out of the stock housing to be able to install their poly bushing, requiring reuse of an old worn out housing, or buying a new costly bushing assembly.  We decided this was cumbersome and unnecessary, so we designed a complete upgrade replacement bracket with a 70A polyurethane bushing preinstalled for a quick bolt-in installation.  Our bracket is precision formed with a CNC machined and TIG welded bushing cup to perfectly match the OEM bracket, and is made from 304 stainless steel for exceptional corrosion resistance.  The result is a complete design solution that creates much crisper shifting with nearly zero added NVH for a more engaging and enjoyable driving experience.

Note: Some shifter arms have a mushroom-shaped end. Use extra care installing our bushing on these arms. Filing this mushroom down makes installation easier, however simply applying sufficient pressure to the back side of the bushing during installation will allow this bushing to install smoothly.

This is the last bushing you will ever want or need for your E28, E30, or E34!

Product Features:

• Pre-installed bushing, NO cutting or burning for installation
• Corrosion resistant 304 stainless steel mounting bracket
• 70A durometer poly bushing for reduced NVH
• Ready to install out of the box
• Replaces Genuine BMW part number 25111220707
• Made in America

Have a newer BMW? Click here.

This fits the following BMWs:        

1987-1991 E30 BMW 318i 318is 318ic 325e 325es 325i 325ic 325is 325ix M3
1987-1988 E28 BMW 528e 533i 535is M5
1987-1989 E24 BMW M6
1993-1995 E34 BMW 525i 530i 535i
1991-1993 E34 BMW M5