F22 M235i/M240i Custom Rear Differential

One of the best upgrades to be made is custom building a differential. There are a lot of options to make improvements to the diff including gear sizing changes, added limited slip units, and limited slip lock-up options. It's easy to overlook the differential when planning your car's upgrades but it's one of the best areas to get return from your modification spending. Using a shorter (numerically higher) gear ratio will give you better acceleration and the limited slip effect will help get that power to the pavement. Changing the limited slip lock-up will change how the car behaves in corners - low lock-up will introduce more wheel spin; a higher lock-up will give more grip to the rear wheels but may induce an understeer condition (too much power pushing the car straight); a variable lock-up will give you the optimum balance. Our experience in diff building, car prep, and racing will ensure we get you the correct custom build for your specific driving conditions.

Gearing Changes: All M235i differentials have welded internal pieces that require special machining and modification. Our diff builder has perfected the process and using a shorter ring and pinion is now no more difficult than any other car. But because of the extensive labor involved, a select number of ratios are offered at this time. Using a shorter gear ratio (numerically higher) will give you better acceleration but will reduce your top speed. The higher ratio puts you at a higher RPM point for any given speed. This puts you further up in the power band, giving you more torque to the ground. Refer to the chart below for examples on the difference.

 

2009 335i, 6-speed manual, 255/30-19" rear tires

(click to expand)

Gear RatioGearSpeedRPM

40 MPH in 4th

3.084th41 MPH2,000 RPM

3.464th40 MPH2,250 RPM

70 MPH Cruise

3.086th69 MPH2,500 RPM

3.466th70 MPH2,800 RPM

5th Gear Speed @ 6,000 RPM

3.085th145 MPH6,000 RPM

3.465th129 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.

 

Limited Slip Options: The M235i sadly did not come with a limited slip unit. Instead, BMW used DTC (Dynamic Traction Control) to cut engine power, apply the brake(s), or a combination of both. A limited slip operates independently from either of those systems. With the LSD installed the DTC system does not engage as often. The LSD transfers torque mechanically to the opposite wheel. It will then allow some wheelspin before the traction control kicks in. If you turn off traction control you still have the torque transfer of the LSD working and then wheel spin. So you can get traction in the corner and some wheelspin out of it to facilitate rotation without engine power being cut so soon. We offer several types of limited slip units for the M235i:

  • traditional 2 or 3-disc LSD (40-60% fixed lock-up)
  • 3-disc LSD with variable ramp angles (user-variable lock-up)
  • Quaife helical (no clutch discs)
  • OS Giken Superlock multi-plate LSD (0-100% lock-up)
  • OS Giken TractionControlDiff multi-plate LSD (0-100% lock-up) (smoother and quieter version of Superlock)

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:
2014+ F22 BMW M235i with manual transmission

2017+ F22 BMW M240i with manual transmission

T#: 390820 | Part#: F22-M235-DIFF
Starting at $1999.00
1999.00 $1999.00
Qty
Free Shipping
Direct Ship, Expected Ship Date: Aug 13, 2021

Select Options

No bearing polishing.
Yes, add REM bearing polishing to your diff build.
Diffs by Turner - Corporate Logo
T#: 343187
|
Part#: DIFFBRGPOLISH
In Stock
$299.00
No gear polishing.
Yes, add REM gear polishing to your diff build.
Diffs by Turner - Corporate Logo
T#: 343188
|
Part#: DIFFGEARPOLISH
In Stock
$199.00
3.08 (stock)
Diffs by Turner - Corporate Logo
T#: 343503
|
Part#: E9X335DIFF308
In Stock
$0.00
2.56
Diffs by Turner - Corporate Logo
T#: 343501
|
Part#: E9X335DIFF256
In Stock
$1000.00
2.81
Diffs by Turner - Corporate Logo
T#: 343502
|
Part#: E9X335DIFF281
In Stock
$1000.00
3.15
Diffs by Turner - Corporate Logo
T#: 587654
|
Part#: F22DIFF315
Expected Ship Date: 1-3 days
$1000.00
Qty: 1
3.23
Diffs by Turner - Corporate Logo
T#: 343504
|
Part#: E9X335DIFF323
In Stock
$1000.00
3.46
Diffs by Turner - Corporate Logo
T#: 343505
|
Part#: E9X335DIFF346
In Stock
$500.00
No limited slip. Keep it an open diff.
2 Clutch LSD
Diffs by Turner - Corporate Logo
T#: 386106
|
Part#: E9XNMDIFF2CLUTCH
Expected Ship Date: 1-3 days
$2100.00
Qty: 1
3 Clutch LSD
Diffs by Turner - Corporate Logo
T#: 386132
|
Part#: F3XDIFF3CLUTCH
Expected Ship Date: 1-3 days
$2300.00
Qty: 1
3 Clutch 30/90 Ramps
Diffs by Turner - Corporate Logo
T#: 587655
|
Part#: F22DIFF3C3090
Expected Ship Date: 1-3 days
$2700.00
Qty: 1
3 Clutch 35/60 Ramps
Diffs by Turner - Corporate Logo
T#: 587656
|
Part#: F22DIFF3C3560
Expected Ship Date: 1-3 days
$2700.00
Qty: 1
Quaife Helical
Diffs by Turner - Corporate Logo
T#: 385790
|
Part#: DIFFQUAIFE46
Expected Ship Date: 1-3 days
$1800.00
Qty: 1
WaveTrac Diff
Diffs by Turner - Corporate Logo
T#: 401298
|
Part#: WAVETRACDIFF
Expected Ship Date: 1-3 days
$1500.00
Qty: 1
F22 M235i Custom Differential
Diffs by Turner - Corporate Logo
T#: 390819
|
Part#: F22-M235-DIFF
Direct Ship, Expected Ship Date: Aug 13, 2021
$1399.00
Qty: 1
$600 Differential Core Charge - DO NOT RETURN TO TURNER, see core charge instructions in box
CoreCharge - Corporate Logo
T#: 390827
|
Part#: DIFF-CORE-60
Direct Ship, Expected Ship Date: Aug 13, 2021
$600.00
Qty: 1
F22 M235i/M240i Custom Rear Differential
$1999.00