Diffsonline Custom Performance Differential - M2 M3 M4 F80 F82 F83 F87

A great upgrade - and common maintenance item - for drivers looking for added acceleration and grip for their F87 M2, F80 M3, or F82/F83 M4! 

Application Notes:
 

• Vehicle production date, or last 7 digits of VIN required.
• Gear oil is sold separately. Red Line 75W110 recommended.
• Requires reuse of original differential bottom cover. 
• Drexler LSD option requires the use of 2 left rear axles

F8X M2/M3/M4 Limited Slip Options

There are a two limited-slip carrier upgrades for the F80/F82/F87 M cars - clutch and helical. 

For purely street use we would recommend a Wavetrac helical. Helical diffs offer advantages in wear resistance and performance over traditional clutches. Torque transfer happens instantly and it doesn't need to sense a spinning wheel first. Lock-up is quicker and smoother and it's less affected by heat than a clutch. The only downside is potentially higher gear whine (but not in all cases). 

For sport /racing duty, we recommend the Drexler 6-Clutch LSD. These diffs feature multiple clutch and spring discs - more clutches equal greater capacity for torque and heat management. 35/40 and 40/50 ramp angles are available. Note: When installing a Drexler LSD, the right rear output shaft must be removed and replaced with a left-side output shaft, part # 33212284615. See below for BimmerWorld recommended related items.

Please feel free to contact us by phone or email to discuss the best M2/M3/M4 differential upgrade that will meet your needs. 

 

REM Polishing

REM treatment is a multi-step light surface polish of the gears and/or bearings that removes small imperfections and high spots on the surface. BMW does some final detailing on their ring & pinion sets that removes most of these imperfections but there is still room for improvement. High spots create heat risers which raise the surface temp of the surrounding metal and leads to imperfections and wear. REM polishing reduces internal temps and friction, improving performance and efficiency. It also makes the ring & pinion quieter with smoother engagement. REM polishing is done on a as-ordered basis and may result in additional build time. REM is a registered trademark of REM Chemicals, Inc.

If you would like to add REM polishing to your custom build, please give us a call for pricing and to place your order.    

 

Core Charge

We're able to offer rebuilt and performance differentials at a reasonable cost due to the use of cores. A "core" is your original used differential that is returned to our diff builder to be recycled into a new, fully-rebuilt diff. If we did not have cores available, and had to buy new factory differentials from BMW, our performance diffs would be four times the price they are now. To keep this upgrade feasible for the entire enthusiast community we rely on having your good, reusable core returned to the diff builder (Diffsonline) within fourteen days of receipt of your new diff. In order to cover the cost of sourcing another used diff, a core charge is applied to your order at the time of processing. This core charge can be refunded when you send back your original diff. Only complete and reusable cores will be eligible for a refund (no blown out, abused, or modified cores please). You must return a diff equal in components and accessories to the one sent to you. 

The core charge on a F8X diff is $1000, which is not included in the price and will be charged separately at the time of processing. Click here for the core policy and instructions. You can also avoid the core charge altogether by sending in your original diff to be rebuilt. Note that this will mean downtime for your vehicle, so we recommended using the core service. 

 

Rebuild Process

While we take in used diffs as cores, what you get is a fully rebuilt and properly set up unit that is often better than what BMW can provide. There is a lot of specialty knowledge required in the diff building industry and Diffsonline has over 20 years of experience in BMW differentials. Nearly all of the major retailers of performance differentials use Diffsonline, even when sold under other brand names.

Rebuilding a diff is a very involved process -
 

• The used diff is disassembled and cleaned
• The outside case (carrier) is stripped of grease, grime, and rust
• The desired limited slip unit is prepped
• The specified gear set is assembled with the LSD
• Any machining of the carrier is done in-house
• New OEM bearings are fitted
• New OEM seals are fitted
• The entire internal assembly is aligned (crucial in avoiding gear whine later on)
• Final assembly and checks
• Carrier is given a fresh coat of black paint
• Shipment to your door in special heavy-duty packaging

The Diffsonline packaging can be reused to send back your core. 

Diffs are shipped without covers and with no fluid inside. 

Diffsonline recommends Red Line 75/110 fluid for this application.  We suggest ordering 3 quarts so that you have enough for a fluid change after break-in. 

Fluid Tip: before installing the diff, stand the diff on its nose and add the correct amount of fluid before installing the cover. This ensures the fluid reaches internal areas that don't get fluid when pumped through the fill hole in the cover.

See below for BimmerWorld recommended related items.

BimmerWorld offers FREE GROUND SHIPPING on all diffs.

Upgrading the differential in your BMW is one of the best ways to improve handling, acceleration, and all-around performance. If you're looking to add limited-slip functionality to get all that power to the ground in the turns, we've got the knowledge to guide you in the right direction. Should you have any questions on BMW diff upgrades or the process, please call or email one of our knowledgeable sales reps.