Upgrading the suspension on your Nissan 240SX is one of the most rewarding modifications you can undertake. Coilover systems provide adjustable damping, ride height, and spring preload, giving you control over the car's cornering, stability, and comfort. Whether you drive an S13, S14, or S15, the installation process shares common steps but requires attention to specific details for each chassis. This guide covers the entire process from preparation to final adjustments, along with trusted brand recommendations to ensure you select a quality kit.

Tools and Materials Needed

Having the right tools on hand before you start saves time and frustration. Beyond the coilover kit itself, gather the following:

  • Jack and jack stands (rated for at least 2 tons)
  • Socket set (metric, 10mm to 19mm) and wrenches
  • Torque wrench (ft-lb and in-lb ranges)
  • Spring compressor (for disassembling stock struts)
  • Breaker bar or impact gun (optional but helpful for stubborn bolts)
  • Pry bar or pickle fork (for separating suspension components)
  • Penetrating oil (like WD-40 or PB Blaster)
  • Anti-seize compound
  • Safety goggles and gloves
  • Jack stands (never rely on the jack alone)
  • Alignment tools (or plan for a professional alignment later)

Many coilover kits come with wrenches for adjusting the lower lock ring, but having a dedicated spanner wrench can make height adjustments easier. If you are working on a 240SX with significant rust, prepare for seized bolts by having a torch available, but use extreme caution near fuel lines and brake components.

Preparing Your 240SX for Installation

Proper preparation ensures a smooth installation and prevents damage to new components. Follow these steps before lifting the car:

  • Park on a level concrete surface and chock the rear wheels (or front, depending on which end you start with).
  • Loosen the lug nuts on all four wheels while the car is still on the ground. This prevents the wheels from spinning when you attempt to break them loose.
  • Clean the strut tower areas and control arm mounting points. Dirt and debris can interfere with measurements and cause binding.
  • Spray penetrating oil on all suspension bolts you plan to remove, especially the lower strut bolts, sway bar end links, and top mount nuts. Let it soak for at least 10 minutes.
  • Have a notebook or phone handy to record ride height settings before disassembly if you plan to match the factory height initially.

For S13 and early S14 models, the factory top mounts are separate from the strut bearing unit, which may need replacement if worn. Inspect your stock top hats for cracking or bearing play while you have them off. Many coilover kits include pillowball top mounts that require periodic maintenance, so check the manufacturer's instructions.

Removing the Factory Suspension

Removing the stock strut assemblies is the most time-consuming part of the job. Work on one corner at a time to avoid confusion with hardware, and keep bolts organized in labeled bags.

Front Suspension Removal

  • Lift the front of the car and place jack stands under the frame rails or pinch welds. Verify stability before proceeding.
  • Remove the front wheels.
  • Unclip the brake line from the strut body. Do not disconnect the brake line; just free it so it does not stretch when the strut drops.
  • Remove the sway bar end link from the strut body. This bolt can be tight; use a hex key or vice grips on the ball joint stud if it spins.
  • Unbolt the brake caliper and hang it from the coil spring with a zip tie or wire to avoid stressing the brake hose.
  • Remove the two lower strut bolts that connect the strut to the steering knuckle. These are typically 17mm or 19mm. You may need to use a pry bar to separate the strut from the knuckle if they are corroded.
  • From inside the engine bay, remove the three or four bolts holding the top mount to the strut tower. Support the strut assembly with one hand while loosening the last bolt.
  • Carefully maneuver the strut assembly out of the wheel well. You may need to rotate it to clear the lower control arm.

If you are reusing the stock top mounts, disassemble the strut with a spring compressor to remove the spring cup and bearing. This is not necessary if your coilover kit includes new top mounts.

Rear Suspension Removal

The rear suspension on the 240SX is a multi-link setup, which means the shock absorber is separate from the spring. To remove the rear shock:

  • Lift the rear of the car and place jack stands under the rear subframe or specified lift points.
  • Remove the rear wheels.
  • Access the top mount of the rear shock in the trunk or cargo area. On a hatchback, you may need to remove interior trim panels. The top mount is secured by two or three nuts, depending on the year.
  • Remove the lower shock bolt that attaches the shock to the rear knuckle or lower control arm. This bolt often requires a ratchet from the underside.
  • Compress the shock by hand or with a pry bar to free it from the lower mount, then remove it from the top.
  • If your coilover kit replaces both the shock and spring, you may also need to remove the rear spring. To do this, lower the rear control arm using a jack, then pull the spring out. Be careful not to let the arm drop unsupported.

Keep all hardware, especially the rubber isolators and bushings, as you may reuse them with certain coilover kits.

Installing the Coilover Kit

With the stock suspension removed, you can now install the new coilovers. Follow the manufacturer’s instructions for assembly, but these general steps apply to most kits.

Front Coilover Installation

  • Assemble the coilover by sliding the spring over the damper body. If the spring is preloaded from the factory, you only need to tighten the lower perch to the recommended setting. Many kits ship with a pre-set spring preload for a standard ride height.
  • Apply anti-seize to the threads of the height adjustment collar to prevent seizing from road salt and moisture.
  • Install the top mount onto the damper shaft. Use the supplied nut and tighten it to the manufacturer’s torque specification. Do not overtighten, as this can damage the damper shaft or bearing.
  • Insert the assembled coilover into the strut tower from the wheel well. Guide the top mount bolts through the holes in the strut tower.
  • Hand-tighten the top mount nuts, then torque them to the specified value (usually 25-35 ft-lb for S13/S14).
  • Align the lower bracket of the coilover with the steering knuckle. Insert the two lower bolts but do not fully tighten them yet—allow some movement for alignment.
  • Reattach the brake caliper and the sway bar end link. Torque all hardware to factory specifications.
  • Check that the brake line is routed securely and is not bound or pinched.
  • Repeat on the opposite side, ensuring both front coilovers are set to the same height measurement before tightening the lower bolts.

Rear Coilover Installation

  • Assemble the rear coilover using the same method as the front. Rear coilovers typically have a separate spring that sits on a lower perch.
  • Install the rear coilover by inserting the top mount through the shock tower from inside the trunk or cargo area. Secure the top mount nuts and torque them.
  • From underneath, align the lower eyelet of the coilover with the lower shock mount on the knuckle or control arm. Insert the bolt and tighten it loosely at first.
  • If your kit includes a separate rear spring (a true coilover design for the rear), install the spring in its cup and seat it properly. Most kits replace the entire assembly.
  • Lower the car onto its wheels before final tightening of the control arm and knuckle bolts to avoid preloading the bushings in a static position. A full tightening should be done with the suspension loaded at ride height.

Torque specifications for suspension bolts are critical. Under-torquing leads to loosening and noise, while over-torquing can break bolts or strip threads. Always use a torque wrench, especially on the steering knuckle bolts.

Adjusting Ride Height and Damping

Coilovers offer two primary adjustments: ride height and damping force. Properly setting these adjustments affects handling, tire wear, and comfort.

Setting Preload and Ride Height

Most coilover kits use a two-piece adjustment system: a lower spring perch for ride height and a lock ring to secure it. Adjust the ride height by turning the lower perch. Do not confuse ride height adjustment with spring preload—changing the lower perch changes the car’s height without altering the spring’s compressed length. Some kits also allow preload adjustment by an upper lock ring. For street use, set the coilovers so the car sits at a height that maintains proper suspension geometry, typically close to the manufacturer’s recommended height. Lowering too much can cause bump steer, reduce travel, and damage oil pans or exhausts on bumps.

To set a consistent height on both sides of the car, measure from the center of the wheel hub to the fender lip. Adjust each corner until the measurements match. On the 240SX, a common street height drops the car 1 to 2 inches from stock. For track use, you may go lower, but ensure adequate suspension travel to prevent bottoming out.

Adjusting Damping Settings

Coilovers have adjustable damping via a knob on the top of the damper (for front) or at the bottom (for rear). Most brands offer 24 to 32 clicks of adjustment. As a starting point, set the damping to the middle of the range. Drive the car on your typical roads and adjust in 4-click increments toward stiffer or softer based on feel. Stiffer settings reduce body roll but transmit more road imperfections. Softer settings improve ride quality but may allow excessive body lean. For daily driving with occasional spirited corners, a setting around 10-12 clicks from full stiff works well on many 240SX setups.

Corner Balancing (Optional)

For track-oriented use, corner balancing ensures each wheel carries equal weight distribution. After setting ride height and damping, take the car to a shop with scales. They will adjust individual corner heights to achieve a cross-weight balance. This step is not necessary for street use unless you notice uneven tire wear or handling issues.

Testing and Alignment

After installing and adjusting the coilovers, you must test the installation and get a professional alignment. Driving with misaligned suspension is dangerous and wears tires quickly.

Initial Test Drive

Lower the car completely and tighten all fasteners to the final torque specifications. Bounce each corner of the car to settle the suspension. Steering: turn the wheel lock-to-lock to ensure the coilovers do not bind or contact anything. Then drive slowly around a parking lot, listening for clunking, rubbing, or excessive noise. If you hear noises, identify the source immediately. Common issues include loose top mount nuts, improperly torqued lower bolts, or coil spring binding.

Professional Alignment

Take the car to a shop familiar with 240SX alignment. A coilover installation almost always affects camber, caster, and toe. The front suspension on S13 and S14 uses adjustable camber on the strut top mounts (if equipped with camber plates) or through offset bushings. The rear has slight adjustability through the multi-link system, but many owners install adjustable arms for fine-tuning. Specify your alignment goals: street driving typically uses 0 to -1 degree front camber, 0 to -0.5 degrees rear camber, and minimal toe. Track setups use more negative camber. After alignment, mark the adjustment positions for future reference.

Brand Recommendations

The market offers many coilover brands for the 240SX, ranging from budget-friendly to race-grade. Here are five reputable brands known for quality, support, and tuning potential. Always verify that the kit is designed for your specific chassis (S13, S14, or S15) to avoid fitment issues.

BC Racing

BC Racing is a popular choice for enthusiasts on a budget. Their BR-series coilovers offer adjustable damping and ride height with a durable build. They are known for good customer support and a wide range of spring rates. BC Racing also offers a custom spring rate option for specific needs. Visit BC Racing for product details.

Fortune Auto

Fortune Auto provides high-quality coilovers with digressive valving for improved response and comfort. Their 500-series and 510-series are well-regarded for street and track use. They also offer adjustable camber plates on front kits. Fortune Auto’s customer service and rebuild program are highly rated. Learn more about Fortune Auto coilovers.

Tein

Tein is a Japanese brand with a strong following in the drifting and performance scene. Their Street Basis and Super Street coilovers offer reliable performance for daily drivers, while the Flex Z and Mono Sport models provide advanced features like EDFC (electronic damping control). Tein coilovers are known for their durability and precise manufacturing. Explore Tein suspension options.

KW Suspensions

KW Suspensions builds premium coilovers made in Germany. Their Variant 1 and Variant 3 systems offer exceptional build quality, stainless steel bodies, and long-term durability. KW coilovers are expensive but provide excellent ride quality and performance. They are often used in competitive motorsport. Check out KW Suspensions.

Stance Suspension

Stance Suspension focuses on daily-driven street cars with a sporty edge. Their GR+ and XR+ coilovers feature adjustable damping and ride height with a comfort-oriented tuning. Stance also offers singles and travel support for lowering extremes. They are a solid mid-range option for enthusiasts who want a balance of performance and comfort.

When choosing a brand, consider your primary use for the car. For occasional street driving, BC Racing or Tein are cost-effective. For aggressive track use, Fortune Auto or KW offer superior control. Always read reviews specific to the 240SX chassis, as spring rate recommendations vary widely.

Maintenance and Longevity

Coilovers require periodic maintenance to perform consistently. Every 10,000 miles or once a year, inspect the dampers for oil leaks, check all fasteners for tightness, and clean the adjustment threads. Apply anti-seize to the height collars to prevent corrosion. If you drive in winter conditions with road salt, wash the suspension thoroughly to prevent rust. Many quality coilovers are rebuildable—send them back to the manufacturer or a specialist when they lose damping or develop leaks. Rebuilding typically costs less than buying new units and restores performance to factory specifications.

Conclusion

Installing coilovers on your Nissan 240SX transforms the car's handling and appearance. By following the steps in this guide—removing the factory suspension, installing the new coilovers, adjusting ride height and damping, and performing a thorough test and alignment—you can achieve a professional-level result in your garage. Choose a coilover brand that matches your driving style and budget, and maintain the system properly to enjoy years of improved performance. Whether you are daily driving, drifting, or road racing, a well-installed coilover setup makes the 240SX even more rewarding to drive.