S13 240sx Awd Conversion Kit: The Ultimate Grip Machine

So, you're thinking about turning your S13 240SX into an AWD monster? You've come to the right place. Let's dive deep into the world of AWD conversion kits for this iconic drift machine. This isn't a bolt-on affair; it's a serious undertaking, but the payoff – unparalleled grip and handling – can be well worth the effort. This article will cover the technical aspects of these kits, what to expect, and what you need to consider before taking the plunge.

Why AWD for an S13?

The 240SX is legendary for its rear-wheel-drive (RWD) configuration, making it a drift king. But RWD isn't always ideal. AWD offers superior traction in various conditions, leading to improved acceleration, cornering, and overall performance, especially in wet or snowy environments. An AWD conversion can transform your 240SX from a sideways specialist to a true all-weather performance machine. Think about it: launching off the line with minimal wheelspin, attacking corners with unwavering stability, and simply having more control in challenging driving conditions. That's the power of AWD.

Understanding the Conversion Kit Components

An AWD conversion kit for an S13 is more than just bolting on a few parts. It's a comprehensive system that fundamentally alters the car's drivetrain. Here's a breakdown of the key components you'll typically find in a quality kit:

Transfer Case

The transfer case is the heart of the AWD system. It splits the engine's power between the front and rear axles. Common donor vehicles for transfer cases in these conversions include Subaru WRX/STI, Nissan Skyline GT-R (R32/R33), and some Mitsubishi Evolution models. The choice of transfer case significantly impacts the overall strength and reliability of the system. Look for a transfer case known for its durability and availability of replacement parts.

Crucially, the transfer case dictates the front-to-rear torque split. Some offer a fixed split (e.g., 50/50), while others utilize more sophisticated electronically controlled systems that can vary the torque distribution based on driving conditions. Electronic systems offer greater adaptability, but require more complex wiring and potentially aftermarket controllers.

Front Differential

The front differential allows the front wheels to rotate at different speeds during cornering, preventing binding and ensuring smooth handling. It's typically sourced from the same donor vehicle as the transfer case (e.g., a WRX front differential to match a WRX transfer case). It is also where new front axles will connect to.

When selecting a front differential, consider its Limited-Slip Differential (LSD) type. Open differentials allow for maximum wheel spin, while LSDs (such as clutch-type, Torsen, or viscous) provide varying degrees of torque biasing, improving traction and reducing wheelspin. A well-chosen LSD can significantly enhance cornering performance.

Front Axles and Hubs

Custom front axles are a necessity, connecting the front differential to the front hubs. These axles need to be of the correct length and spline count to mate with both the differential and the hubs. Many kits use custom fabricated front knuckles and hubs, or modified factory 5-lug hubs. These allow for correct mounting and compatibility of the front wheel bearings and suspension components.

Axle strength is paramount. Choose axles made from high-quality materials like 4340 chromoly steel. Weak axles are a common failure point in AWD conversions, especially with increased horsepower.

Driveshafts

You'll need both a front and a rear driveshaft. The rear driveshaft will likely need to be custom-made or modified to connect the transfer case to the S13's existing rear differential. The front driveshaft will connect the transfer case to the front differential. These need to be properly balanced for smooth, vibration-free operation.

When dealing with custom driveshafts, pay close attention to the Universal Joints (U-joints) and slip yokes. Choose high-quality components that can handle the increased torque loads of the AWD system. Also, the driveshaft's critical speed should be far above what the car will actually reach. Failing to do so will cause catastrophic failure of the driveshaft.

Transmission Adapter

Depending on the chosen transfer case and the S13's engine (SR20DET, KA24DE, or other swaps), a transmission adapter might be necessary to mate the transfer case to the transmission. This adapter ensures proper alignment and secure mounting. Be sure to confirm which adapter is needed before committing to the conversion. Typically, the adapter will have the same bolt pattern on each side as the transmission and transfer case. It is important that they line up perfectly, or damage can occur to the transmission or transfer case.

Crossmember Modifications

Significant modifications to the front crossmember and potentially the transmission tunnel are usually required to accommodate the transfer case and front differential. This often involves cutting, welding, and reinforcing the chassis. This is where fabrication skills are essential. Failure to properly reinforce the chassis can lead to structural weakness and potential damage.

It's common to see custom-fabricated crossmembers designed to integrate the front differential mounting points. These crossmembers not only provide structural support but also optimize the suspension geometry and drivetrain alignment.

Suspension and Steering

The front suspension needs to be compatible with the new front hubs and axles. Some kits use modified S13 suspension components, while others require swapping to a different suspension system altogether. Clearance for the front axles is a major concern. Steering rack placement may also need to be altered to avoid interference with the drivetrain.

Consider upgrading to heavier-duty springs and dampers to handle the added weight and increased grip of the AWD system. Also, pay attention to the front Anti-Roll Bar (Sway Bar). The new AWD setup will likely necessitate a different sway bar to maintain proper handling balance.

ECU and Wiring

If the transfer case uses an electronically controlled torque split system, you'll need to integrate it with the car's ECU. This may require a standalone ECU or a piggyback controller to manage the AWD system. Proper wiring and calibration are crucial for optimal performance.

Also, ensure the ABS system is functioning correctly with the AWD setup. Incompatibility can lead to unpredictable braking behavior. It may be necessary to disable or recalibrate the ABS system to account for the different drivetrain configuration.

Choosing the Right Kit (or Going Custom)

Several companies offer AWD conversion kits for the S13. Research thoroughly and choose a kit from a reputable manufacturer with a proven track record. Consider the following factors:

Completeness: Does the kit include all necessary components, or will you need to source additional parts?
Quality: Are the components made from high-quality materials?
Support: Does the manufacturer offer technical support and documentation?
Donor Vehicle Compatibility: What donor vehicles are used for the transfer case and differential? Are these parts readily available?

Alternatively, you can opt for a completely custom solution. This route offers greater flexibility but requires extensive fabrication skills and engineering knowledge. A custom build is generally more expensive and time-consuming but allows for a tailored solution to meet specific performance goals.

Things to Consider Before You Start

An AWD conversion is a complex and time-consuming project. Before you begin, carefully consider the following:

Budget: AWD conversions can be expensive. Factor in the cost of the kit, donor parts, custom fabrication, and labor.
Skill Level: Do you have the necessary mechanical and fabrication skills? If not, consider hiring a professional.
Time Commitment: Be prepared to spend a significant amount of time on this project. It's not a weekend job.
Legality: Check your local laws and regulations regarding vehicle modifications. Some modifications may not be street legal.
Weight: An AWD system adds significant weight to the car. This can impact handling and fuel economy.
Horsepower Goals: Don't attempt to convert your 240SX to AWD until you have decided on a realistic target horsepower number. This target will help select the proper components that can handle the added power.

Conclusion

Converting your S13 240SX to AWD is a significant undertaking, but the rewards can be substantial. With proper planning, execution, and a healthy dose of patience, you can transform your drift machine into an ultimate grip machine that's ready to tackle any road condition. Just remember to do your research, choose the right kit (or plan your custom build carefully), and be prepared for the challenges ahead. The result? A 240SX that defies expectations and delivers an unparalleled driving experience.