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- Differential and Gearing Upgrades
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This product was last offered at the strikethrough price on
06-14-2026
This product was last offered at the strikethrough price on
06-14-2026
This product was last offered at the strikethrough price on
05-03-2026
This product was last offered at the strikethrough price on
05-03-2026
This product was last offered at the strikethrough price on
05-03-2026
This product was last offered at the strikethrough price on
05-03-2026
TMS E90/E92/E82 (NON M) solid differential mounts are designed around current Grand Am Cup regulations, derived from, and currently used in TMS racecars. Thick Delrin casings are used as the non-metallic solid bushing. Replacing your differentials rubber mounts with this kit will result in a snappier feel when cornering and better suspension performance. You save money by never having to replace the stock rubber mounts that fail due to old age and fatigue. These bushings are CNC machined in the USA and made with high-grade materials.
This product was last offered at the strikethrough price on
06-14-2026
This product was last offered at the strikethrough price on
06-14-2026
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
This product was last offered at the strikethrough price on
06-14-2026
This product was last offered at the strikethrough price on
06-14-2026
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
This product was last offered at the strikethrough price on
06-13-2026
This product was last offered at the strikethrough price on
06-13-2026
This product was last offered at the strikethrough price on
06-14-2026
This product was last offered at the strikethrough price on
06-14-2026
This product was last offered at the strikethrough price on
06-14-2026
This product was last offered at the strikethrough price on
06-14-2026
This product was last offered at the strikethrough price on
06-14-2026
This product was last offered at the strikethrough price on
06-14-2026
Convert your open differential to a locked differential without the costly expense of an LSD replacement.
Get your car ready for aggressive track driving or drifting without purchasing or replacing your differential. The weld-in plates strengthen your diff and allow both wheels to engage simultaneously giving you a more predictable and capable track car.
An open differential allows the wheels to spin at different speeds and sends power to the wheel with the least amount of traction. This may be a good feature for your regular everyday driver but limits you on the track. The weld-in plates simulate a driving experience similar to a limited-slip differential allowing you to put power to both wheels in a low traction area or initiate drifts.
Features and benefits:
Added strength to your differential gears
Converts from open differential
Fabricated to fit in the spider gears for an easier weld and increased confidence
Made from 7 gauge mild steel, formed to fit
This product was last offered at the strikethrough price on
05-03-2026
This product was last offered at the strikethrough price on
05-03-2026
This product was last offered at the strikethrough price on
05-03-2026
This product was last offered at the strikethrough price on
05-03-2026
This product was last offered at the strikethrough price on
05-03-2026
This product was last offered at the strikethrough price on
05-03-2026
This product was last offered at the strikethrough price on
05-03-2026
This product was last offered at the strikethrough price on
05-03-2026
This is a complete differential to change the gearing of a manual transmission E90/E92 325i, 328i, or 330i (not for xi models) to a 3.64 ratio final drive. The standard gearing on the manual transmission cars is 3.15 or 3.23, making this E90 diff significantly shorter. This diff is from a 330i automatic where the gear ratio has to be shorter to make up for the transmission gearing differences and extra weight. This will dramatically improve acceleration on any 325i, 328i or 330i INSTANTLY! If you are looking for better off-the-line or rolling acceleration, and are willing to sacrifice a little top-speed (some of us don't get up to 150mph), this is one of the best ways to achieve it with almost no downside. There are few things that can improve your 0-to-60 and 0-to-100 times as much as shorter gearing, and this differential is clearly a best "bang-for-buck" solution for dramatically better acceleration. Since this is an Original BMW part it carries the same BMW two year warranty as any other new part. So there's no need to take a chance on a used part from a private seller. (former BMW part number 33107519944)
Changing gear ratio changes the RPM range for any given speed. Use the chart below for examples of speed vs RPM changes for the 3.64 diff.
2006 330i, 6-speed manual, stock 3.15 gears, 255/35-18" rear tires
Gear RatioGearSpeedRPM
40 MPH in 4th
3.154th40 MPH2,100 RPM
3.644th40 MPH2,400 RPM
70 MPH Cruise
3.156th70 MPH2,500 RPM
3.646th70 MPH2,900 RPM
5th Gear Speed @ 6,000 RPM
3.155th142 MPH6,000 RPM
3.645th123 MPH6,000 RPM
Why 5th? Because 6th does not have the mechanical advantage to get past wind resistance at these speeds - it is more of a cruise/overdrive gear. Using 5th for comparison purposes is much more relevant than having to take into account wind direction, resistance, grade, elevation, tire sizing, etc. These numbers are for comparisons among gear ratios only, not to determine what your E90 will top out at.2006-2011 325i or 328i, 6-speed manual, stock 3.23 gears, 255/35-18" rear tires
(click to expand)
Gear RatioGearSpeedRPM
40 MPH in 4th
3.234th40 MPH2,150 RPM
3.644th40 MPH2,400 RPM
70 MPH Cruise
3.236th70 MPH2,600 RPM
3.646th70 MPH2,900 RPM
5th Gear Speed @ 6,000 RPM
3.235th138 MPH6,000 RPM
3.645th123 MPH6,000 RPM
Speed in 5th gear at 6,000 RPM is for theoretical and comparison purposes only. It doesn't mean that these speeds are actually reachable.
A $100 refundable core charge must be added at the time of order. This core charge can be refunded when you ship your original diff back to us.
This item fits the following BMWs with manual transmission only:
2006-2011 E90 BMW 325i 328i 330i - Sedan
2006-2012 E91 BMW 325i 328i - Wagon
2007-2013 E92 BMW 328i - Coupe
2007-2013 E93 BMW 328i - Convertible