XYZ Racing Street Advanced Coilovers — Maserati BITURBO SI φ52 welding (PCD: 4X98) 1986-1991

The Biturbo SI’s twin-turbo layout put real power through a chassis that was never given suspension to match, and three decades on, tired factory dampers are the single biggest reason these cars still feel vague under load. The Street Advanced coilover corrects that without turning the car into a track special – spring rate and ride height that suit a road-and-occasional-track Biturbo, not a full race build.

For a 1986-1991 SI, that balance matters. This generation rides on a φ52 strut body with a 4×98 PCD, and the welding-fit design keeps the geometry the SI was built around rather than forcing a bolt-in compromise. It’s the right spec for owners who drive their Biturbo rather than trailer it.

What this coilover does for your 1986-1991 Maserati BITURBO SI φ52 WELDING (PCD: 4X98)

Ride height becomes adjustable rather than fixed by tired factory springs, so you can correct the sag and stance that thirty-plus-year-old dampers inevitably develop. The 720-way damping adjustment gives a genuinely usable spread between a compliant setting for cracked B-roads and a firmer one for a track day, rather than the two or three coarse steps you’d get from a cheaper unit. Because the kit is matched to the SI’s φ52 strut diameter and 4×98 PCD, the geometry stays correct instead of drifting under load the way a generic strut swap can. The result on the road is less turbo-lag-induced squat under boost and a front end that holds its line rather than pushing wide mid-corner. For a car this light on the front axle relative to its power, that composure is the difference between confidence and constant correction.

About the Street Advanced coilover

Street Advanced is XYZ’s core product, refined over years of development and validated in competition before being tuned down for road use. It’s built for exactly this brief: a car that sees normal road use with the occasional track day, rather than a dedicated circuit weapon. The 720-way damping adjustment is the headline spec, giving fine enough resolution to find a setting that suits your specific Biturbo rather than settling for "close enough." XYZ positions it as essential kit for drivers who want genuine control and pace without living with a stripped-out race ride every day. Construction follows XYZ’s usual coilover format, matched here to the SI’s φ52 strut body and welding-type fitment so the kit integrates with the car’s original suspension mounting rather than requiring modified brackets.

Fitment for the Maserati BITURBO SI φ52 WELDING (PCD: 4X98) (1986-1991)

This kit is built specifically for the Maserati Biturbo SI chassis produced between 1986 and 1991, matched to the φ52 strut diameter and 4×98 wheel PCD that this generation uses. The welding-type design fits the SI’s original strut mounting rather than a bolt-in adapter. Confirm your car sits within this year range and strut spec before ordering, as Biturbo suspension architecture changed across the model’s production run.

What buyers also search for

• Maserati Biturbo SI suspension upgrade for road and occasional track use
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• Biturbo SI φ52 strut replacement for 1986-1991 cars
• Maserati Biturbo Street Advanced coilover fitment and spec guide
• 4×98 PCD coilover options for classic Maserati Biturbo models

Spec your Street Advanced kit to your exact Biturbo SI below and configure yours to match how you actually drive it.