XYZ Racing Circuit Master Coilovers — Nissan 240/260/280 Z φ51 welding 1970-1978

The S30-generation 240/260/280 Z runs strut-type front suspension on inserts Nissan stopped supporting decades ago, and worn fifty-year-old strut tubes are why most restored Z cars ride softer than their chassis can use. XYZ Racing’s Circuit Master coilover in φ51 Welding spec fixes that at the root: a fresh 51mm strut tube is welded straight into the existing housing, giving the front end a rigid new mounting point instead of asking a bolt-in cartridge to work inside a housing it was never built for.

That matters because Circuit Master is built for sustained circuit lap-time work, not an occasional track day. On a car this light, with an inline six sitting well forward of the front axle, getting the strut mount solid again is what lets the kit’s adjustment range actually change how the car behaves, instead of being soaked up by decades-old metal.

What this coilover does for your 1970-1978 Nissan 240/260/280 Z Φ51 Welding

With the strut tube welded solid, the 9,720-way adjustment range built into Circuit Master’s valving has something firm to work against, so changes at the knob show up at the contact patch instead of being lost in old strut-tube flex. Three external adjustment knobs let you separate compression and rebound per corner, which on a long-nosed, front-heavy S30 means you can carry more front damping to control nose dive under braking without stiffening the rear enough to unsettle the semi-trailing-arm axle on corner exit. Ride height comes down through the threaded body rather than cut springs, so you can drop the car to a track-usable stance while keeping the front-to-rear rake historic Z racers rely on for weight transfer. On track, that means a front end that turns in on command and a rear that stays planted through direction changes instead of hopping over mid-corner bumps.

About the Circuit Master coilover

Circuit Master sits at the top of XYZ Racing’s line-up alongside the brand’s Drift Spec and Tarmac Rally dampers, and it’s the version XYZ’s own racing teams run and develop on circuits worldwide before it reaches a customer car. The headline figure is 9,720 distinct adjustment combinations across the kit’s three external knobs, giving compression and rebound enough range to be set for a specific circuit rather than a general-purpose compromise. That range comes from a deliberately small internal oil-hole design in the valving, which is what makes the fine adjustment possible – the trade-off is a faint clicking noise over sharp bumps, which is normal behaviour for this valving, not a fault. Every part of the kit assumes repeated hard laps rather than the occasional pothole, and the φ51 Welding front end applies that same thinking to a chassis like the S30 Z that never had a factory bolt-in coilover option.

Fitment for the Nissan 240/260/280 Z Φ51 Welding (1970-1978)

This kit is built for the Nissan 240Z, 260Z and 280Z (S30 chassis, chassis code NI01) across the full 1970-1978 production run, in φ51 Welding spec for cars retaining their original strut housings. Because the front end is a welded conversion rather than a bolt-in cartridge, confirm your strut housings are original and unmodified before ordering.

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Circuit Master in φ51 Welding spec is built to order for this exact S30 Z fitment – pick your spec below to get started.