Are you a BMW enthusiast or a racer looking to unlock the full potential of your car’s transmission? Look no further! In this comprehensive guide, we’ll delve deep into the world of BMW’s 5-speed gearbox. Whether you’re interested in its specifications, power handling capabilities, or are seeking a high-performance solution, we’ve got you covered.

BMW’s 5-Speed Gearbox: A Closer Look

Before we explore the racing solutions, let’s get to know the BMW 5-speed gearbox. This transmission has been a staple in various BMW models, providing a balance of performance and efficiency. Here’s what you need to know:

BMW ZF Transmission 5-Speed: A Perfect Match

BMW and ZF have had a long-standing partnership when it comes to transmissions. The ZF 5-speed gearbox is no exception. It complements BMW’s engineering prowess, delivering power to the wheels with precision and efficiency. Whether you have a classic BMW or a modern one, the ZF 5-speed transmission can enhance your driving pleasure.

While these transmissions are known for their reliability, there’s a common issue that has affected many of them: the detents. In earlier models, a proper detent channel liner was lacking, which could lead to sticking detents. The consequences of this issue included the shift knob leaning towards 5th gear, difficulty engaging 5th gear and reverse, and overall frustration for drivers.

Applications

The ZF 5-speed gearbox has found its home in various BMW models, including the E36 M3 and 328i, E46 328i and 330i, as well as the Z3 2.8 and M Roadster/Coupe. Its reputation for robustness and precision has made it a popular choice for BMW owners looking to enhance their driving experience.

Additionally, the ZF 5-speed transmission can be retrofitted to many race applications, making it a versatile option for motorsport enthusiasts.This transmission is known for its durability, making it a favorite among racers. It weighs approximately 77 lbs, striking a balance between strength and weight savings. The ZF 5-speed gearbox’s capability to harness additional power ensures that you spend more time accelerating, thanks to faster shifts and reduced driveline losses.

The ZF 5-speed transmission has gained popularity for example in the Miata community. With adapter packages available, you can pair this transmission with Mazda BP and Honda K series engines for a potent combination. These packages offer bolt-in solutions for NA and NB Miata chassis, allowing for custom RWD K series projects.

ZF S5D 320 Z and ZF S5D 310 Z Transmissions: BMW Designation

The ZF S5-31 transmission, known by various names, including “S5D 310Z” by BMW, is a product of ZF Friedrichshafen’s engineering excellence. Designed for use in longitudinal engine applications, this transmission has earned a reputation for its precision and performance. Rated for a formidable 310 Nm (229 lbf·ft) of torque, it’s a powerhouse in the world of manual transmissions.

However, it’s worth noting that transmissions made from September 1995 onward were manufactured with a reinforced design and carry the name “S5D 320Z.” The S5D 320Z is rated for an increased 320 Nm of torque.

BMW’s transmission designation system provides insights into various aspects of the transmission:

S: Transmission type – “S” denotes a manual transmission.

5: Number of forward gears.

D: Type of top gear – “D” stands for Direct gear.

310: Maximum input torque rating in Newton-meters (Nm).

Z: Code letter of the manufacturer – “Z” indicates ZF, the manufacturer of the transmission.

Difference Between ZF S5D 320 Z and ZF S5D 310 Z:

While there are two different ZF part numbers, ZF S5D 320 Z and ZF S5D 310 Z, they are essentially identical in most aspects. Both versions are used across various BMW models and share the same gear ratios and torque ratings. The primary difference lies in the shifter coupling to the selector rod. If you’re buying a used unit, consider replacing the coupling with an upgraded one, bringing it to 96 M3 specification.

In summary, both ZF S5D 320 Z and ZF S5D 310 Z transmissions are excellent choices, but ensure that the unit you select matches your specific BMW model and year.

Gear Ratios: The Heart of Performance

One of the key elements that define a manual transmission’s performance is its gear ratios. The ZF S5-31 excels in this aspect, offering a carefully crafted set of gear ratios that cater to both power and efficiency. Here are the gear ratios for the ZF S5-31:

These gear ratios ensure that the ZF S5-31 can deliver power smoothly across a wide range of driving conditions. From quick acceleration in first gear to efficient highway cruising in fifth gear, this gearbox strikes a balance between performance and fuel economy.

ZF S5D 320 Z Transmission (Part 23001434485):

When searching for a ZF S5D 320 Z or ZF S5D 310 Z transmission, it’s essential to know which cars they were originally installed in. These transmissions are known for their reliability and find homes in various BMW models.

This transmission can be found in the following BMW vehicles:

Please note: The earlier E36 transmissions (e.g., 95 M3, 325i) are not the same as the 96-99 E36 transmissions.

Maintaining and Enhancing Your ZF 5-Speed Gearbox

Proper maintenance is crucial to keep your ZF 5-speed gearbox in peak condition. Consider using automatic transmission fluid (ATF) such as Redline D4 ATF, a preferred choice among BMW racers.

Additionally, it’s essential to address common issues like worn detents. New upgraded liners with reduced friction materials, detents, springs, caps, and snap rings are available to enhance the performance of gears 1-5 and reverse.

When installing the transmission, keep in mind that some components may require special drift installation tools.

Power Handling

Now, the big question – how much power can a ZF 5-speed handle? While the exact power capacity may vary depending on factors such as maintenance, usage, and specific model variations, the ZF 5-speed gearbox is generally considered robust. It can comfortably handle power outputs of up to 300-350 horsepower.

However, it’s essential to keep in mind that pushing a transmission to its limits without proper maintenance or upgrades can lead to premature wear and potential issues. If you’re planning to modify your BMW for higher power levels, it’s advisable to consult with experienced mechanics and consider reinforcing or upgrading the transmission components as needed.

So in its stock form, it’s no slouch, but for high-power applications exceeding 500hp, there are better heavy-duty options available. With minor alterations, cars equipped with this transmission have shown a remarkable 2-3% reduction in driveline losses. In practical terms, this equates to an increase of 6-10 horsepower on an average M3 Prepared-class engine.

When equipped with special Gear sets with upgraded counter and input shafts, this gearbox have been tested up to a whopping 1100hp/1100Nm in drag and drift racing.

GearMotive Dogbox: Your Racing Solution

Now, if you’re serious about taking your BMW to the racing circuit and need a high-performance solution, GearMotive has you covered. The BMW ZF S5D dogbox gearset is designed to fit M3, 325, and other compatible car models. Here’s what sets it apart:

• Shifter Mechanisms: GearMotive’s dogbox gearset comes with completely rebuilt shifter mechanisms. This ensures maximum robustness and rigidity, essential for racing applications.
• Clutch Shaft: The clutch shaft in this gearset is not only stronger than the original but can also be customized for other splines. This flexibility makes it suitable for a wide range of racing setups.
• High-Power Options: For vehicles pushing over 500hp, GearMotive offers heavy-duty models with counter and input shafts that have been rigorously tested to handle extreme power levels.
• Easy Installation: Installing GearMotive’s dogbox gearset is straightforward and doesn’t require extensive modifications.
• Additional Options: GearMotive provides various options, including HD input shafts with different splines, prop adapters and adapters for replacing ZF GS5-39 or Getrag gearboxes.
• Performance short shifter: It’s constructed using premium high-grade materials, with precise CNC milling and anodization for added durability  and adjustability to block reverse gear or 4-5th gears.
• Engine Adaptability: GearMotive can assist you in fitting any engine type to your ZF S5D dogbox with the right adapter kit, ensuring compatibility with your racing setup.
• Bell Housing Welding: If you require bell housing welding fitments, GearMotive can either provide these services or recommend partners who can assist you.

While this transmission is designed for specific BMW models, it can also be retrofitted to most race applications, including other M50-based engines with the proper gear linkage and driveshaft.

Suitable models for dogbox build

Number in Bellhousing:

In conclusion, the BMW 5-speed gearbox, particularly the ZF S5D, is a robust and versatile transmission that can handle a wide range of power levels. However, for those seeking maximum performance on the racetrack, GearMotive’s dogbox gearset is the ultimate solution. With its enhanced features and adaptability, it’s the key to unlocking your BMW’s racing potential. Don’t wait; take your racing game to the next level with GearMotive’s dogbox gearset and leave the competition in the dust!