The Datsun 240Z remains one of the most iconic Japanese sports cars ever built, celebrated for its timeless lines and engaging driving dynamics. But even the most well-preserved example can benefit from targeted suspension and handling upgrades. While the factory setup was impressive in its day, modern driving expectations and aftermarket engineering have unlocked levels of road performance and cornering stability that the original engineers could only dream of. This guide covers the essential modifications—from springs and dampers to bushings, tires, and alignment—that will transform your 240Z into a precise, confidence-inspiring machine whether you’re carving backroads or setting lap times.

Understanding the Datsun 240Z Suspension Architecture

Before selecting parts, it helps to know what you’re working with. The 240Z uses a MacPherson strut front suspension and a Chapman strut rear suspension (a variant of the MacPherson strut). This design was chosen for its simplicity and low cost, but it has inherent limitations in terms of camber control and bump steer. Key components include:

  • Front strut assembly: Consists of a shock absorber, spring, and upper mount. The strut acts as both a suspension member and a locating point for the steering knuckle.
  • Rear strut assembly: Similar to the front, but also serves as the upper link for the semi-trailing arm rear suspension geometry.
  • Lower control arms (front): A‑arm type that locates the lower end of the strut and attaches to the crossmember.
  • Semi-trailing arms (rear): Locate the rear wheel hub and control toe and camber changes during suspension travel.
  • Sway bars (anti-roll bars): Connect left and right sides through links and bushings to resist body roll during cornering.
  • Rubber bushings: Original compliant rubber allows flex and degrades over time, introducing slop.

Because of the strut design, any change to ride height alters camber and toe, making alignment critical after upgrades.

Key Upgrades for Improved Handling

Coilover Systems vs. Spring/Shock Combinations

The most dramatic improvement comes from replacing the tired factory dampers and springs. Two main paths exist:

  • Full coilover conversion: Coilovers replace the strut with a threaded body that carries the spring on the shock. This allows independent ride height and spring preload adjustment. High-end coilovers also offer adjustable damping (rebound and compression). Brands like Techno Toy Tuning and BC Racing produce Z‑specific kits that bolt in with minimal modification. Coilovers give the most flexibility for autocross, track days, or aggressive street driving.
  • Performance springs + gas shocks: For a street-focused car that doesn’t need ride height adjustability, pairing progressive‑rate lowering springs with high‑quality gas shocks (like Koni or KYB) is a proven, cost‑effective upgrade. Eibach and H&R make springs for the 240Z that drop the car about 1–1.5 inches while improving spring rates. The trade‑off is less tuning range and a fixed ride height.

For most drivers who want both performance and daily‑drivable comfort, a set of adjustable coilovers with a wide damping range is the best investment. Look for setups that include camber plates at the front to recover alignment after lowering.

Sway Bars and Their Impact

Increasing sway bar thickness dramatically reduces body roll without a harsh ride. Stock 240Z sway bars are thin (typically 20mm front, 16mm rear). Upgrading to a 22–24mm front bar and a 20–22mm rear bar, combined with polyurethane or spherical end links, sharpens turn‑in and keeps the tires flatter through corners. However, going too large on the rear can induce oversteer; balance the bars with spring rates and tire grip. A typical starting point is a 22mm front and 19mm rear adjustable bar set to the softest setting, then fine‑tune from there.

Polyurethane Bushings: Benefits and Installation

Original rubber bushings in the control arms, sway bar mounts, and steering rack allow excessive deflection and vague steering feel. Replacing them with polyurethane bushings (from Energy Suspension or SuperPro) firms up the chassis, reduces wheel hop, and improves steering response. Polyurethane is more durable than rubber and resists oil and heat degradation. Expect slightly increased NVH (noise, vibration, harshness) — a worthwhile trade‑off for precision. For the most extreme setups, spherical bearings (rod ends) in the control arms eliminate all bushing deflection but are noisy and transmit every road imperfection; they’re best reserved for dedicated track cars.

Wheel and Tire Considerations

Upgrading wheels and tires is perhaps the most visible and immediately felt change. The contact patch is where all the suspension work meets the road.

  • Width and offset: Stock 240Z wheels are 5.5–6 inches wide with a relatively high offset (+29mm). Widening to 7–8 inches front, 8–9 inches rear allows mounting 215–245 section width tires. Lower offset (e.g., +0 to +15mm) pushes the wheels outward, improving track width and cornering stability, but requires rolled fenders or flares. Careful fitment is necessary to avoid rubbing.
  • Tire compound: Ultra‑high performance summer tires (like the Michelin Pilot Sport 4S, Bridgestone Potenza RE‑71RS, or Yokohama Advan A052) offer enormous grip and progressive breakaway. All‑season tires are a compromise and mute much of the suspension upgrade’s benefit.
  • Unsprung weight: Reducing wheel weight (e.g., forged or flow‑formed alloys) lowers unsprung mass, allowing the suspension to follow road irregularities more faithfully, improving traction and ride quality. A set of Konig or Enkei wheels can save 8–12 lbs per corner versus steel wheels.

Don’t forget proper wheel studs and hub‑centric rings if the new wheels have a larger center bore. Torque all lug nuts to spec and recheck after a few miles.

Braking System Upgrades for Consistent Performance

Increased power and grip demand more braking capability. The stock 240Z brakes (single‑piston calipers with solid rotors) can be overwhelmed, especially on track or during spirited mountain driving.

  • Pad compound: Upgrade to a performance pad (e.g., Hawk HP+ or EBC Yellowstuff) for better initial bite and fade resistance. Pads with a higher operating temperature work best but may be noisy or dusty for street use.
  • Rotors: Slotted or drilled rotors improve gas venting and keep the pad surface clean. Drilled rotors are prone to cracking under hard use; slotted (or slotted and dimpled) are more durable. Cross‑drilled rotors are acceptable for street use if made from high‑quality cast iron.
  • Stainless steel brake lines: Replace the rubber hoses with stainless‑braided Teflon lines. This eliminates expansion under pressure, giving a firmer pedal and more consistent modulation.
  • Brake fluid: Flush with a high‑boiling‑point DOT 4 or DOT 5.1 fluid (e.g., Motul RBF 600 or Castrol SRF). Old fluid absorbs moisture and leads to pedal fade.

For serious track work, consider a big‑brake kit (such as Wilwood or Datsun Spirit) with multi‑piston calipers and larger rotors, but this usually requires 16” or larger wheels.

Precision Alignment and Setup

Even the best parts are wasted without proper alignment. The 240Z’s strut suspension means that lowering the car increases negative camber (especially in front), which can be beneficial for cornering but excessive camber leads to inner edge tire wear and reduced straight‑line braking stability. A good street‑performance alignment for a lowered 240Z is:

  • Front camber: −0.5° to −1.5°
  • Front caster: +3.0° to +5.5° (more caster improves straight‑line stability and steering return)
  • Front toe: 0 to 1/16” total toe‑in
  • Rear camber: −1.0° to −2.0°
  • Rear toe: 1/8” to 3/16” total toe‑in

Adjustable camber plates (front) and adjustable control arms (rear) are necessary to achieve these settings on a lowered car. Many coilover systems include camber plates. For the rear, aftermarket eccentric bushings or adjustable semi‑trailing arm brackets allow camber and toe adjustment.

After any suspension component change, corner weight the car if possible. Setting ride heights evenly side‑to‑side and cross‑weighting (diagonal weight) reduces the car’s tendency to understeer or oversteer unpredictably.

Additional Chassis Bracing and Structural Improvements

The 240Z chassis is unibody, and the strut towers can flex under load, especially after stiffer springs and sticky tires. Reducing flex improves suspension geometry consistency and driver confidence.

  • Front strut tower brace: A triangulated bar connecting the tops of the front strut towers prevents them from splaying apart. Bolted or welded designs are available; a welded brace offers more rigidity but is permanent.
  • Rear strut tower brace: Similarly, tying the rear strut towers together reduces chassis twist. Many aftermarket bars are available for the 240Z.
  • Subframe connectors / frame rails: The 240Z has relatively thin floorpan and frame rails that can flex. Installing “frame rail” reinforcements (like those from Bad Dog Parts) stiffens the center section drastically, improving steering response and reducing cowl shake.
  • Roll bar / cage: A bolt‑in roll bar (even a 4‑point) adds significant stiffness and safety. For a street car, a simple half‑cage behind the seats is a good compromise.

Chassis bracing should be installed before final alignment, as the structural changes can shift the suspension pick‑up points.

Conclusion

Transforming a Datsun 240Z from a vintage cruiser into a corner‑carving champion requires a systematic approach. Start with a solid foundation: refresh or replace the bushings, invest in quality coilovers or matched springs/shocks, and upgrade the sway bars. Then choose wheels and tires that suit your performance goals, pair them with a capable brake system, and set the alignment to match your driving style. Finally, tighten the chassis with braces to let the suspension do its job without fighting body flex.

With these upgrades, your 240Z will reward you with razor‑sharp turn‑in, flat cornering, and feedback that connects you to the road. Whether you’re attacking a canyon road or lapping a track, the upgraded suspension will make every drive an event. The classic looks remain, but the handling will feel modern—proving that a well‑sorted Datsun 240Z can still shame cars costing many times more.