A Guide To Aftermarket Adjustable Suspension Arms For The Nissan 240sx
The Nissan 240SX, known as the Silvia in other markets, remains a beloved platform for drifting, track days, and spirited street driving. Its lightweight chassis, rear-wheel drive configuration, and responsive engine make it a potent and engaging car. However, like any car, its factory suspension has limitations, especially when pushed beyond its original design parameters. One of the most impactful modifications you can make to improve the 240SX's handling is upgrading to aftermarket adjustable suspension arms. But what exactly do these arms do, and how do they contribute to better performance?
Understanding the Role of Suspension Arms
Suspension arms, also known as control arms, are the link between the chassis and the wheel hubs. They control the wheel's movement in relation to the car's body. The factory suspension arms on the 240SX are generally made of stamped steel with rubber bushings. While adequate for normal road use, these components can flex under high loads, leading to unpredictable handling and reduced precision.
Here's a breakdown of the key suspension arms typically addressed in aftermarket upgrades:
Front Lower Control Arms (FLCA)
The FLCAs control the lower portion of the front wheel hub. Adjustable FLCAs allow for adjustments to camber and caster. Camber refers to the angle of the wheel relative to the vertical axis. Negative camber (where the top of the wheel leans inward) is generally desirable for improved cornering grip, as it helps to keep the tire contact patch flat on the road during turns. Caster refers to the angle of the steering axis relative to the vertical axis. Increasing caster generally improves straight-line stability and steering feel. Adjustable FLCAs allow you to dial in the ideal camber and caster settings for your specific driving style and track conditions.
Front Upper Control Arms (FUCA)
The FUCAs control the upper portion of the front wheel hub. Like FLCAs, adjustable FUCAs primarily allow for camber adjustments. In some cases, they may also allow for minor caster adjustments. Replacing FUCAs is often necessary when lowering the car significantly, as the factory arms may not provide enough camber adjustment to compensate for the change in suspension geometry. Furthermore, aftermarket FUCAs often offer improved ball joint articulation, allowing for greater suspension travel without binding.
Rear Lower Control Arms (RLCA)
The RLCAs control the lower portion of the rear wheel hub. Adjustable RLCAs primarily allow for camber adjustments at the rear. Adjusting rear camber can be crucial for balancing the car's handling and maximizing rear grip, particularly in drifting applications. Additionally, adjustable RLCAs can sometimes allow for minor wheelbase adjustments, which can fine-tune the car's handling characteristics.
Rear Upper Control Arms (RUCA)
Similar to RLCAs, RUCAs control the upper portion of the rear wheel hub and primarily adjust camber. They work in conjunction with the RLCAs to achieve the desired camber setting. Replacing RUCAs is often necessary when lowering the car significantly, as the factory arms may not provide enough camber adjustment. They also typically offer improved ball joint articulation.
Tension Rods (or Compression Rods)
These rods, located in the front suspension, control the caster angle. Adjustable tension rods allow for precise adjustments to caster, which can significantly impact steering feel and straight-line stability. They also contribute to reducing deflection under braking.
Toe Arms
Toe arms, located in the rear suspension, control the toe angle of the rear wheels. Toe refers to the angle of the wheel relative to the direction of travel. Rear toe adjustments are critical for controlling oversteer and understeer. Adjustable toe arms allow for precise adjustments to rear toe, which can be used to fine-tune the car's handling characteristics and improve stability.
Benefits of Aftermarket Adjustable Suspension Arms
The advantages of upgrading to aftermarket adjustable suspension arms are numerous:
- Improved Handling: Adjustable arms allow you to optimize the suspension geometry for your specific driving needs. This translates to improved cornering grip, reduced body roll, and more predictable handling.
- Increased Adjustability: The primary benefit is the ability to precisely adjust camber, caster, and toe angles. This allows you to fine-tune the car's handling characteristics to suit your driving style and track conditions.
- Correction of Lowering Effects: When lowering a 240SX, the suspension geometry is altered, often resulting in excessive negative camber. Adjustable arms allow you to correct this geometry, restoring proper handling and preventing uneven tire wear.
- Increased Strength and Durability: Aftermarket suspension arms are typically made from stronger materials, such as high-strength steel or aluminum. This improves their resistance to bending and flexing under high loads, enhancing durability and performance.
- Improved Bushings: Many aftermarket arms feature upgraded bushings, such as polyurethane or spherical bearings. These bushings reduce deflection and improve responsiveness, leading to more precise handling.
Material Considerations
Aftermarket suspension arms are typically constructed from two primary materials:
- Steel: Steel arms are generally more affordable and offer excellent strength and durability. They are a good choice for street cars and those who prioritize reliability over weight savings. However, they are heavier than aluminum arms.
- Aluminum: Aluminum arms are lighter than steel arms, which can improve overall vehicle performance. They also offer good strength, but they may be more susceptible to damage in extreme conditions. Aluminum arms are a good choice for track cars and those who prioritize weight savings.
Bushing Selection
The type of bushing used in the suspension arms also plays a significant role in their performance:
- Rubber Bushings: These are the standard bushings found in most factory suspension arms. They provide good vibration damping and noise reduction, but they are also the softest and most prone to deflection.
- Polyurethane Bushings: Polyurethane bushings are stiffer than rubber bushings, which reduces deflection and improves responsiveness. However, they can also transmit more noise and vibration into the cabin. They are a good compromise between performance and comfort.
- Spherical Bearings: Spherical bearings offer the least amount of deflection and provide the most precise handling. However, they also transmit the most noise and vibration into the cabin. They are typically used in high-performance applications where maximum responsiveness is desired. Spherical bearings can also require more frequent maintenance.
Installation and Alignment
Installing aftermarket suspension arms is a relatively straightforward process, but it is essential to follow the manufacturer's instructions carefully. It is also crucial to have the car professionally aligned after installing adjustable suspension arms. A proper alignment is essential for achieving the desired handling characteristics and preventing uneven tire wear. You will need the car aligned to ensure that all suspension parts work together in harmony. An alignment without prior planning and understanding is useless.
Conclusion
Upgrading to aftermarket adjustable suspension arms is a highly effective way to improve the handling and performance of your Nissan 240SX. By allowing for precise adjustments to camber, caster, and toe angles, these arms enable you to optimize the suspension geometry for your specific driving needs. Careful consideration should be given to the materials used in the arms and the type of bushings they employ, as these factors will significantly impact their performance and durability. Remember to have the car professionally aligned after installation to ensure optimal handling and tire wear. With the right setup, adjustable suspension arms can transform your 240SX into a more capable and enjoyable machine.
Choosing the right suspension arm is a critical decision that should be made considering your budget and what you will do with your car. Suspension technology is very advanced and it is worth it to educate yourself and make an informed decision.