Powerflex BMW Differential and Gearing Upgrades for BMW 3 Series E46 (1999-2005)

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Upgrading various parts of the differential can have tremendous benefits in your car's performance. It's easy to forget that the differential is a source for making your car faster and handle better so it's often overlooked. The engine is not the only place to make the car faster. Our differential options vary from gearing upgrades to limited slip conversions. You can purchase the ring & pinion gear sets on their own (professional installation required) or have us build a diff around your own specifcations. The options are almost endless! Every custom-built diff is fully rebuilt with seals and bearings. We also design and supply bushing options to reduce driveline wind-up, finned differential covers for better cooling, and more!

Ratio Changes - Changing the differential gearing is one of the best and most-effective upgrades you can make on any BMW (old or new). By using a shorter (numerically higher) final drive ratio you are increasing your RPM relative to road speed - this puts you in a more powerful RPM range than before! Since you're in a 'meatier' part of the power band you're now putting down more power/torque to the ground. If you can trade outright top speed for faster acceleration at daily speeds then this is the perfect upgrade for you.

Limited Slip Upgrades - Sadly, many BMWs today are not equipped with a limited slip (posi-traction) differential. BMW has tried to compensate by using traction control that cuts power at the engine or applies the brakes to retard wheel spin (or a combination of both). But nothing beats the function and feel of a a true LSD which may be why BMW continues to use them in M cars. Our LSD upgrades can be done a number of different ways - a factory-type limited slip unit with either 2 or 3 clutch packs, helical type, OS Giken unit, or something truly custom. We can also vary ramp angles and setup to change the limited-slip behavior under acceleration, deceleration, and cornering. Need a custom diff? Call or e-mail to have a quote.
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Powerflex Polyurethane Rear Differential Front Position Bushing - E46...
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Powerflex - Corporate Logo
T#:362735
Part#: PFR5-4621
In Stock
$ 42.99 USD
Free Shipping on orders $49 and up

Differential bushings are responsible for keeping the differential in solid alignment while dampening drivetrain vibration. While OE rubber bushings are fine when they are new from the factory, aged and worn out rubber bushings create a multitude of issues that can range from annoying to dangerous. As a factory bushing ages, it begins to harden and become brittle. When this happens the bushing will actually shrink and allow for movement at the differential mounting point. At this point, the differential is free to shift under load causing a noticeable clunking noise under acceleration and deceleration and massively increasing the stress on the driveshaft and axles. Manual transmissions suffer the worst from this as it can make shifting difficult since the differential will shift when the clutch is engaged and disengaged.

By replacing these bushings with full polyurethane, the movement is eliminated since the mounting point is supported by a much stiffer material that will not harden or shrink over time. This means less stress on the driveshaft and axles and greater longevity of supporting components. 

Powerflex Black Series bushings are the ultimate in track and race bushings. Featuring 95A durometer polyurethane, Black Series bushings are 25% stiffer than street bushings. Engineered to perform, Powerflex performance polyurethane control arm bushings offer a supreme level of control, while still providing enough comfort for the street, with advanced polyurethane that reduces NVH that often accompanies lesser bushings. Expect improved acceleration response, more direct shifting feel and overall improved drivetrain composure with Powerflex performance polyurethane bushings.

Poweflex is a leading manufacturer of aftermarket suspension bushings. Using state of the art design and manufacturing, all replacement bushings are engineered to out-perform and out-last the ones that came in the car. Each line of bushings is meticulously tested and then re-tested to ensure perfect fitment and enduring quality through the life of the vehicle. A full lifetime warranty backs every one of their products and demonstrates the level of confidence and commitment Powerflex has to their customers. 

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Powerflex BMW E46 - Z4 Rear Diff Front Mount
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Powerflex - Corporate Logo
T#:33913480
Part#: PFR5-4621H
In Stock
$ 42.99 USD
Free Shipping on orders $49 and up

The Powerflex Rear Diff Front Mount Bushing for the BMW E46 3 Series and Z4 is a premium upgrade designed to enhance the stability and performance of the drivetrain. Here’s an alternative description:

  • High-Performance Polyurethane: Powerflex bushings are made from advanced polyurethane, which is significantly more durable than standard rubber. This material resists wear, deformation, and the effects of heat, oil, and contaminants, making it a long-lasting solution for high-performance applications.

  • Purpose: The rear differential front mount is subjected to high levels of stress during acceleration and cornering. Over time, the stock rubber bushing can degrade, causing excessive movement in the differential. The Powerflex bushing eliminates this movement, allowing for improved drivetrain control and reducing unwanted flex.

  • Key Features:

    • Enhanced Rigidity: By replacing the softer OEM rubber with Powerflex’s stiffer polyurethane, this bushing minimizes differential movement under load, resulting in improved throttle response and sharper handling.
    • Improved Longevity: Unlike the factory rubber mounts, which can crack and wear out over time, the polyurethane construction ensures long-lasting performance and reliability.
    • Performance-Oriented Design: Powerflex’s bushing is engineered to handle the increased demands of spirited driving and track use, offering better control without sacrificing comfort.
  • Benefits:

    1. Improved Power Transfer: Reducing differential movement helps direct more power to the wheels, improving acceleration and delivering a more connected driving feel.
    2. Better Handling and Stability: With less flex in the differential, the car becomes more stable, particularly during cornering and high-speed driving, enhancing overall handling precision.
    3. Durable and Maintenance-Free: Polyurethane bushings are resistant to common automotive chemicals, heat, and road debris, providing a set-and-forget solution that lasts longer than rubber components.
  • Fitment: This bushing is designed as a direct replacement for the front mount of the rear differential in BMW E46 3 Series and Z4 models. It installs easily, without requiring modifications, and offers an immediate improvement in drivetrain response.

In summary, the Powerflex Rear Diff Front Mount Bushing is an essential upgrade for BMW E46 and Z4 drivers who want to improve drivetrain rigidity, reduce flex, and enhance overall performance. This bushing provides a durable, long-lasting solution that’s perfect for both street and track use, delivering better power transfer and handling.

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Powerflex BMW E46 M3 Rear Diff Rear Mount
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Powerflex - Corporate Logo
T#:34080712
Part#: PFR5-4620H
In Stock
$ 147.99 USD
Free Shipping on orders $49 and up

The Powerflex Heritage Rear Differential Mount for the BMW E46 M3, available through outlets like Turner Motorsport, is an ideal upgrade for enthusiasts seeking to enhance the performance and durability of their car's rear differential while preserving its classic appearance. The Heritage Series is tailored for those who prefer a more subtle aesthetic than the brightly colored bushings typical of Powerflex's standard line.

Key features:

  • Heritage Polyurethane Composition: The bushings are made from high-performance polyurethane, providing superior resistance to wear, cracking, and degradation compared to the original rubber mounts. This helps improve handling without compromising ride comfort.
  • Classic Appearance: Unlike the regular Powerflex bushings, which come in bright colors (yellow or purple), the Heritage Series bushings are finished in a muted dark green/black, allowing them to blend seamlessly into the undercarriage of the vehicle, ideal for those who prefer a more OEM look.
  • Enhanced Handling and Stability: The rear diff mount works to reduce the unwanted movement of the differential, which translates to improved traction, better throttle response, and more consistent handling in high-load scenarios like hard cornering or acceleration. This significantly reduces wheel hop and enhances rear-end stability.
  • Direct Fitment: These mounts are designed to be a direct replacement for the factory bushings, requiring no additional modifications. This makes them an excellent choice for both DIY and professional installs.
  • Perfect for Street and Track Use: Combining durability and flexibility, this mount is suitable for E46 M3s that see a mix of daily driving and occasional track use, offering the best of both worlds by improving responsiveness while maintaining comfort.

Turner Motorsport often emphasizes the balance of performance and OEM-like comfort with these mounts, making them an excellent choice for those wanting to upgrade their rear differential mounting without detracting from the car's original feel.

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Powerflex Performance Polyurethane Differential Bushings - E46, E83, ...
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Powerflex - Corporate Logo
T#:378993
Part#: PFR5-4625X2
In Stock
$ 94.99 USD
Free Shipping
$ 94.99 USD
Free Shipping

Differential bushings are responsible for keeping the differential in solid alignment while dampening drivetrain vibration. While OE rubber bushings are fine when they are new from the factory, aged and worn out rubber bushings create a multitude of issues that can range from annoying to dangerous. As a factory bushing ages, it begins to harden and become brittle. When this happens the bushing will actually shrink and allow for movement at the differential mounting point. At this point, the differential is free to shift under load causing a noticeable clunking noise under acceleration and deceleration and massively increasing the stress on the driveshaft and axles. Manual transmissions suffer the worst from this as it can make shifting difficult since the differential will shift when the clutch is engaged and disengaged.

By replacing these bushings with full polyurethane, the movement is eliminated since the mounting point is supported by a much stiffer material that will not harden or shrink over time. This means less stress on the driveshaft and axles and greater longevity of supporting components. 

Powerflex street bushings are ideal for street driven vehicles and those that see occasional autocross or track time. Need bushings for a dedicated track car? Powerflex Black Series bushings are the ultimate in track and race bushings. Featuring 95A durometer polyurethane, Black Series bushings are 25% stiffer than street bushings. Engineered to perform, Powerflex performance polyurethane control arm bushings offer a supreme level of control, while still providing enough comfort for the street, with advanced polyurethane that reduces NVH that often accompanies lesser bushings. Expect improved steering feel, turn in, more responsive handling and overall improved chassis composure with Powerflex performance polyurethane control arm bushings.

Poweflex is a leading manufacturer of aftermarket suspension bushings. Using state of the art design and manufacturing, all replacement bushings are engineered to out-perform and out-last the ones that came in the car. Each line of bushings is meticulously tested and then re-tested to ensure perfect fitment and enduring quality through the life of the vehicle. A full lifetime warranty backs every one of their products and demonstrates the level of confidence and commitment Powerflex has to their customers. 

Show More Show Less