Function And Form Coilovers 240sx

Alright, so you're looking into Function and Form (F&F) coilovers for your 240SX. Good choice! They're a popular option for a reason. This article will break down everything you need to know, from the technical specs to installation considerations, helping you make an informed decision and potentially tackle the project yourself. We'll assume you've already got some basic wrenching experience.

Understanding the Function and Form Philosophy

Function and Form, often abbreviated as F&F, aims to strike a balance between performance and affordability. They're not the cheapest coilovers on the market, but they're also not the most expensive. Their focus is on providing a noticeable improvement in handling without breaking the bank. For the 240SX, this translates to a more responsive and predictable ride, ideal for street use with occasional track days.

Before diving into the specifics of the 240SX kit, let's clarify some common coilover terms:

Coilover: A suspension assembly combining the coil spring and shock absorber (damper) into a single unit. This allows for adjustable ride height and, in some cases, damping (shock stiffness).
Spring Rate: Measured in pounds per inch (lbs/in) or kilograms per millimeter (kg/mm), it describes how much force is required to compress the spring one inch or millimeter. Higher spring rates mean stiffer springs.
Damping (Rebound and Compression): Damping refers to the shock absorber's ability to control the movement of the spring. Rebound damping controls how quickly the shock extends after being compressed. Compression damping controls how much resistance the shock offers when being compressed. Adjustable damping coilovers allow you to fine-tune these characteristics.
Ride Height: The distance between the ground and a specific point on the car's chassis. Coilovers allow you to adjust this, lowering or raising the car as desired.
Preload: The amount of compression already applied to the spring when the suspension is at rest. Adjusting preload can affect ride quality and handling, but it's not the primary way to adjust ride height on most coilovers.

F&F Type 1 vs. Type 2 Coilovers for 240SX

Function and Form typically offers two main lines of coilovers that may be applicable to the 240SX:

Type 1: These are usually their entry-level coilovers. They offer fixed damping (non-adjustable) but still provide adjustable ride height. They're a good option for those primarily concerned with lowering their car and improving handling slightly without the complexity of damping adjustment.
Type 2: The Type 2 coilovers feature adjustable damping, allowing you to fine-tune the suspension to your driving style and road conditions. This added adjustability comes at a higher price point.

Which one is right for you? If you're primarily interested in aesthetics and a small handling improvement, the Type 1 might suffice. However, if you plan on doing track days, spirited driving, or want the ability to tailor the suspension's feel, the Type 2 is the better choice. Always verify model availability and specific features for the 240sx with the vendor before purchase.

Spring Rates and Damping

The specific spring rates and damping curves used in F&F coilovers are proprietary, meaning F&F doesn't publicly release this detailed information. However, you can generally expect them to be a noticeable step up from the factory springs. For a 240SX, typical spring rates might be in the range of 6-8 kg/mm (336-448 lbs/in) in the front and 5-7 kg/mm (280-392 lbs/in) in the rear. These are just estimates; always check the product specifications for the exact values.

For Type 2 coilovers, the damping adjustment range usually covers a spectrum from fairly soft to quite firm. This allows you to dial in a comfortable ride for daily driving and then stiffen things up for better control on the track.

Installation Considerations for Your 240SX

Installing coilovers on a 240SX is a moderately challenging task that can be tackled by experienced DIYers. Here's a breakdown of the process and potential pitfalls:

Preparation is Key: Gather all necessary tools, including a jack, jack stands, socket set, wrenches, spring compressors (if you're removing the old springs from the factory struts), penetrating oil, and potentially a breaker bar. A torque wrench is essential for tightening fasteners to the correct specifications.
Safety First: Always use jack stands to support the car. Never work under a vehicle supported only by a jack. Disconnect the negative battery terminal to prevent accidental electrical shorts.
Removing the Old Suspension: This involves disconnecting the sway bar end links, brake lines (be careful with brake fluid!), and any other components attached to the struts. Use penetrating oil liberally to loosen stubborn bolts. Pay attention to the order in which you remove things; it will help with reassembly.
Installing the Coilovers: Follow the manufacturer's instructions carefully. Adjust the ride height to your desired level *before* tightening all the bolts. Make sure the springs are properly seated in their perches. Ensure proper orientation of the shock body.
Torque to Spec: Use a torque wrench to tighten all bolts to the manufacturer's specified torque values. Over-tightening can damage the threads or components. Under-tightening can lead to loose suspension parts.
Brake Lines: Ensure the brake lines have enough slack and aren't being stretched or pinched by the new suspension setup. You might need to slightly bend the hard lines or use extended brake lines for lower ride heights.
Sway Bar End Links: After lowering the car, check the angle of the sway bar end links. If they are at a severe angle, consider using adjustable end links to restore proper sway bar function.
Alignment: This is the most crucial step. After installing coilovers, you *must* get a professional wheel alignment. Lowering the car significantly alters the suspension geometry, and driving without a proper alignment will lead to uneven tire wear and poor handling.

Potential Challenges

Rust: 240SXs are getting old, and rust is a common problem. Be prepared for rusty bolts that may break or be difficult to remove. Penetrating oil and patience are your friends.
Stripped Threads: Exercise caution when tightening bolts. Stripping threads can be a major headache. If you encounter stripped threads, you may need to use a thread repair kit (e.g., Heli-Coil) or replace the affected component.
Incorrect Ride Height Adjustment: Properly adjusting ride height requires measuring from a consistent point on the chassis to the ground. Measure on level ground. Make sure both sides are as equal as possible.
Knocking Sounds: These can be caused by various issues, such as loose bolts, improperly installed sway bar end links, or worn-out bushings. Double-check all connections and components.

Fine-Tuning Your Suspension

Once the coilovers are installed and the car is aligned, you can start fine-tuning the suspension. If you have Type 2 coilovers with adjustable damping, experiment with different settings to find what works best for you. Start with a relatively soft setting and gradually increase the damping until you achieve the desired level of control and comfort.

Remember, suspension tuning is a subjective process. What feels good to one driver may not feel good to another. The best way to find the optimal settings is to experiment and pay attention to how the car responds. Take notes of your settings so you can revert back if needed.

Conclusion

Function and Form coilovers offer a good balance of performance and affordability for the 240SX. They're a popular choice for street cars with occasional track use. Understanding the different types of coilovers, spring rates, damping, and installation considerations will help you make an informed decision and ensure a successful installation. Remember to prioritize safety, use the correct tools, and get a professional wheel alignment after installation. With a little patience and effort, you can significantly improve the handling and appearance of your 240SX with F&F coilovers.