What the car is and where it came from
The Lancia Delta S4 is a Group B rally car built by Lancia in 1985 and 1986. Abarth helped engineer its twincharged engine. It replaced the 037. It used a tubular space frame chassis.
How it works, in terms someone would actually use
The Delta S4 places its 1,759 cc inline-four engine midship. It drives all four wheels. The engine uses both a supercharger and a turbocharger at once. This twincharging reduces turbo lag at low rpm. The car’s layout prioritises traction on loose surfaces.
What it gets right
It solves for traction and throttle response on gravel and snow by combining midship weight distribution, all-wheel drive, and twincharging. It evolved directly from the 037 to meet Group B’s escalating demands.
What it does not
It does not offer verified power figures beyond the 325 hp (242 kW) supercharger-only output of the earlier 037 engine. It does not provide evidence of production numbers beyond 28 complete chassis and fewer than 100 Stradale road versions.
What it changed
It redefined forced-induction packaging in rallying. Its 1,759 cc capacity exploited the FIA’s 1.4x multiplier for forced induction engines, placing it in the under 2,500 cc class with a minimum weight of 890 kg.
Who it is for, and who it is not
It is for engineers, rally historians, and students of motorsport regulation. It is not for collectors seeking documented road-car provenance or drivers seeking usable dynamics data.
Is it worth your time
Yes — if you want to understand how Group B’s regulatory logic shaped extreme rally engineering. No — if you seek a drivable road car or verifiable performance data beyond what the sources state.
