Turner Custom Limited Slip Differentials - E60

A custom differential is one of the best upgrades to have done to your BMW. Not only can you get more performance but you can also get rid of the open diff in non M BMWs or M Variable limited slip diff. It's easy to forget about the rear axle when you're considering performance upgrades but changing the gearing is in the top 3 things to do to make the car faster. A custom diff is also a rebuilt unit with new seals, bearings, and limited slip unit.
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Turner Performance Differential - E60 525/528/530
Diffs by Turner - Corporate Logo
T#:391179
Part#: E606CYLDIFFKT
In Stock
Sale - Save 15% $4,718.00
$3,999.95
Sale - Save 15% $4,718.00
$3,999.95
This is a completely rebuilt and upgraded replacement for your factory differential. The rebuild starts with replacing all seals and bearings, then adding a Helical lsd unit and freshly REM polished ring and pinon. *Differentials ship without fluid and without a cover* *Cost includes $400 core charge*
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E60 545i/550i Differential Upgrade - Custom Options
Diffs by Turner - Corporate Logo
T#:338769
Part#: TMS21534
Direct Ship, Expected Ship Date: Oct 7, 2021
Starting at $1,999.00
Free Shipping
Starting at $1,999.00
Free Shipping
Changing the rear gearing on your E60 V8 is one of the best performance upgrades you can make. The shorter gearing will help accelerate the car quicker by placing the engine in a stronger part of the power band for any given speed. Being in that 'meatier' part of the power band means more torque is available at the wheels. And there is almost no downside!

The stock 545i or 550i with a manual transmission has a 2.81 final drive ratio. It's a relatively tall (numerically low) drive ratio because of the V8's torque output. But using a shorter gear (numerically higher) will take advantage of that torque output even more and give dramatically better acceleration. We rebuild the stock BMW diff with the new gear ratio, new bearings, and new seals. So not only do you get a performance improvement but also a rebuild of a potentially troublesome component. We can also add a limited-slip unit to get better traction.

By changing the gearing, you are changing the speed in relation to engine RPM. The 545i begins to make most of its torque by 2,500 RPM. With the original gear ratio, 25 MPH is 2nd gear at 2,250 RPM. With shorter 3.46 gearing at 25 MPH in 2nd you're now at 2,750 RPM - much deeper into the power band! At 70 MPH in 6th you are right at the start of the torque curve, which means you get much more thrust and maybe no need to downshift! Here are more examples of the gearing and speed differences -

2008 E60 550i, 6-speed manual, 275/30-19" rear tires
(click to expand)
Gear RatioGearSpeedRPM
40 MPH in 4th
2.814th40 MPH1,800 RPM
3.154th40 MPH2,000 RPM
3.464th41 MPH2,250 RPM
3.914th41 MPH2,500 RPM
70 MPH Cruise
2.816th70 MPH2,350 RPM
3.156th69 MPH2,500 RPM
3.466th69 MPH2,750 RPM
3.916th70 MPH3,150 RPM
5th Gear Speed at Redline
2.815th168 MPH6,500 RPM
3.155th157 MPH6,500 RPM
3.465th143 MPH6,500 RPM
3.915th126 MPH6,500 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 car will top out at.

Limited Slip Options The 545i/550i did not come from BMW with a limited-slip differential (posi-traction). Instead, they relied on the throttle electronics and/or brake application to limit wheelspin. The problem with this system is that as soon as it detects wheelspin the electronics cut engine power first. On later models with DSC the brakes will also be applied to the spinning wheel. And without limited-slip (an 'open' diff) it means that power is really only being directed to one wheel (not both rear wheels) - the infamous 'One Tire Fire'. Lifting the inside wheel in a corner can result in useless wheel spin, then engine power cutoff, which is futile when trying accelerate out of a corner. Instead, a limited slip differential (LSD) will transfer power from the inside to the outside wheel that has a lot more traction. We can also vary how much torque is transferred (the 'lock-up') so that you can still transfer torque and get some wheelspin at the same time (great for drifting/autocross!).

Core Charge. If we are building a diff from our own stock a refundable core charge will apply until we get your original diff back. You have a maximum of 30 days from the time you receive the diff to send it back us for a refund. Click here for more detail and explanation of the core charge.

FAQ: For a full FAQ on the custom diff process, click here.

This item fits the following BMWs:
2004-2010 E60 BMW 545i 550i manual transmission
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E60 M5, E63 M6 Differential Upgrade - Custom Options
Diffs by Turner - Corporate Logo
T#:338777
Part#: TMS21533
Direct Ship, Expected Ship Date: Oct 11, 2021
Starting at $1,999.00
Free Shipping
Starting at $1,999.00
Free Shipping
A custom differential is one of the best upgrades to have done to your E60 M5 and M6. Not only can you get more performance but you can also address the weak points in the M Variable limited slip diff. It's easy to forget about the rear axle when you're considering performance upgrades but changing the gearing is in the top 3 things to do to make the car faster. A custom diff is also a rebuilt unit with new seals, bearings, and limited slip unit.

Gearing The E60 M5 diff comes with a relatively short 3.62 gear ratio. They could use a shorter gear because the engine redline is so high - the car has a long power band and the gear spacing allows you to stay well within that range. There's always more acceleration to be had with a shorter gear set. BMW Motorsport supplies 3.91 or 4.10 options and there are other gear ratios to select in our custom builds. We sell a lot of 3.91 gear sets for the M5 because it works seamlessly with the SMG transmission. Other ratios may have issues with shifting, especially in full auto mode. Your speed vs RPM obviously changes with a different gear set. Use the chart below for examples of the differences.

2008 E60 M5, 7-speed SMG, 285/35-19" rear tires
(click to expand)
Gear RatioGearSpeedRPM
40 MPH In 4th
3.624th40 MPH2,500 RPM
3.914th40 MPH2,750 RPM
4.104th40 MPH2,800 RPM
70 MPH Cruise
3.627th70 MPH2,600 RPM
3.917th70 MPH2,875 RPM
4.107th70 MPH3,000 RPM
6th Gear Speed at Redline
3.626th182 MPH8,250 RPM
3.916th169 MPH8,250 RPM
4.106th161 MPH8,250 RPM
Why 6th? Because 7th does not have the mechanical advantage to get past wind resistance at these speeds - it is more of a cruise/overdrive gear. Using 6th 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 M5/M6 will top out at.

Limited Slip Options The M5's M Variable locking differential is genius when it's working properly. Unfortunately, as many M3/M5/M6 owners have come to find, the system only has a service life of 80,000 miles (sometimes less) and then the viscous unit inside starts to fail (is your's clunking?). We can rebuild the internals and bring it back to a perfectly-functioning viscous M Variable unit. Or you may choose to lose the variable lock in favor of a traditional clutch-type or helical diff with a set locking. We also build diffs with Quiafe, Kaaz, and OS Giken (favorite of the Turner racing team) limited slip units.

Core Charge. If we are building a diff from our own stock a refundable core charge will apply until we get your original diff back. You have a maximum of 30 days from the time you receive the diff to send it back us for a refund. Click here for more detail and explanation of the core charge.

FAQ: For a full FAQ on the custom diff process, click here.

This item fits the following BMWs:
2006-2010 E60 BMW M5
2006-2010 E63 E64 BMW M6
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