F3X 335i/435i Manual Limited Slip and Gearing Differential Upgrade

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 335i/435i differentials have welded internal pieces that require special machining and modification. Our diff builder has perfected the process and using a shorter 3.46 ring and pinion is now no more difficult than any other car. But because of the extensive labor involved, the 3.46 is currently the only gear option offered at this time but it's perfect for keeping the N55 engines on the boost. 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.

2014 335i, 6-speed manual, 255/30-19" rear tires(click to expand) Gear Ratio Gear Speed RPM
40 MPH in 4th3.23 4th 40 MPH 2,047 RPM3.46 4th 40 MPH 2,192 RPM70 MPH Cruise3.23 6th 70 MPH 2,570 RPM3.46 6th 70 MPH 2,752 RPM5th Gear Speed @ 6,000 RPM3.23 5th 138 MPH 6,000 RPM3.46 5th 129 MPH 6,000 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 335i/435i 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 F30/F32 limited slip units:
  • traditional 2 or 3-disc LSD (40-60% fixed lock-up - more than the factory M Performance)
  • 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:
    2012+ F30 BMW 335i - Sedan
    2014+ F32 BMW 435i - Coupe
    2014+ F33 BMW 435i - Convertible
    2014+ F36 BMW 435i - Gran Coupe
    T#: 340310 | Part#: TMS216177
    Starting at $2399.00
    2399.00 $2399.00
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    Direct Ship, Expected Ship Date: Aug 13, 2021

    Select Options

    No REM Bearing Polish.
    Yes, Add REM Bearing Polishing.
    Diffs by Turner - Corporate Logo
    T#: 343187
    |
    Part#: DIFFBRGPOLISH
    In Stock
    $299.00
    No REM Gear Polish.
    Yes, Add REM Gear Polishing.
    Diffs by Turner - Corporate Logo
    T#: 343188
    |
    Part#: DIFFGEARPOLISH
    In Stock
    $199.00
    No Limited Slip Upgrade, Keep The Open Diff.
    2 Clutch
    Diffs by Turner - Corporate Logo
    T#: 394195
    |
    Part#: F30DIFF2CLUTCH
    Expected Ship Date: 1-3 days
    $2400.00
    Qty: 1
    3 Clutch
    Diffs by Turner - Corporate Logo
    T#: 394196
    |
    Part#: F30DIFF3CLUTCH
    Expected Ship Date: 1-3 days
    $2700.00
    Qty: 1
    3 Clutch 30/90 Ramps
    Diffs by Turner - Corporate Logo
    T#: 386133
    |
    Part#: F3XDIFF3CLUTCHVR
    Expected Ship Date: 1-3 days
    $3100.00
    Qty: 1
    3 Clutch 35/60 Ramps
    Diffs by Turner - Corporate Logo
    T#: 587898
    |
    Part#: F3X335DIFF3C3560
    Expected Ship Date: 1-3 days
    $2000.00
    Qty: 1
    Quaife Helical
    Diffs by Turner - Corporate Logo
    T#: 394207
    |
    Part#: DIFFQUAIFEF30
    Expected Ship Date: 1-3 days
    $1700.00
    Qty: 1
    OS Giken
    Diffs by Turner - Corporate Logo
    T#: 343320
    |
    Part#: DIFFOSGIKENTRAC
    In Stock
    $2000.00
    3.23 (stock)
    Diffs by Turner - Corporate Logo
    T#: 343545
    |
    Part#: F3XN55DIFF323
    In Stock
    $0.00
    2.56
    Diffs by Turner - Corporate Logo
    T#: 390869
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    Part#: F3XN55DIFF256
    Expected Ship Date: 1-3 days
    $1000.00
    Qty: 1
    2.81
    Diffs by Turner - Corporate Logo
    T#: 390870
    |
    Part#: F3XN55DIFF281
    Expected Ship Date: 1-3 days
    $1000.00
    Qty: 1
    3.08
    Diffs by Turner - Corporate Logo
    T#: 343503
    |
    Part#: E9X335DIFF308
    In Stock
    $0.00
    3.46
    Diffs by Turner - Corporate Logo
    T#: 343546
    |
    Part#: F3XN55DIFF346
    In Stock
    $500.00
    F3X 335i/435i Manual Limited Slip And Gearing Differential Upgrade
    Diffs by Turner - Corporate Logo
    T#: 386130
    |
    Part#: F3X-335-435MTDIF
    Expected Ship Date: 1-3 days
    $1399.00
    Qty: 1
    $1000 Core Charge (Refundable)
    CoreCharge - Corporate Logo
    T#: 343543
    |
    Part#: F3XN55DIFF
    Direct Ship, Expected Ship Date: Aug 13, 2021
    $1000.00
    Qty: 1
    F3X 335i/435i Manual Limited Slip and Gearing Differential Upgrade
    $2399.00