The road version of the famous rally car is expected to sell for around $1 million
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A rare 1985 Lancia Delta S4 Stradale is expected to fetch around AU$1 million when it goes under the hammer next week.

Due to be auctioned by Bonhams on February 6, this example has only driven 3300 kilometres since new, and still has its original Alcantara seats and steering wheel – along with its original Italian documentation and books. The successful bidder will be the car’s third owner.

The S4 Stradale is the road-ready version of the famous Delta S4 rally car, of which Lancia had to make 200 to enter the World Rally Championship.

It is estimated fewer than 80 exist today, and even fewer in this standard original condition, as many owners have modified them to look like Corse rally cars.

The Stradale kept true to its rally cousin, using the same 1759cc engine and tubular space frame construction – although the engine was fitted with a smaller K26 turbocharger than the rally-ready racer.

The Abarth-designed engine was both supercharged and turbocharged to reduce turbo lag, which was groundbreaking for its time. It produced 186kW at 6750rpm and 292Nm at 4500rpm, was paired with a five-speed manual transmission, and the car weighed just 1200kg.

To make the Stradale more comfortable, sound deadening and air conditioning was installed, and to save money the body panels were made out of polyester resin.

But it had its fair share of problems. The supercharger compressor leaked oil frequently, it had a weak clutch which overheated, and the road car's chassis wasn’t reinforced as much as the racer's so it had issues with rigidity.

The last Delta S4 Stradale to be auctioned was auctioned featured the same Rosso red exterior paint and Alcantara interior as the vehicle you see here, along with 2200kms on the odometer... but the chassis numbers differ. It was sold in April 2019 at RM Sotheby’s for AU$2 million.

Raced for only 13 months in the mid-'80s, the Delta S4 is one of the most sought after Group B rally cars in the world.

Also on offer at the same Bonhams auction is another Lancia, albeit one of a different nature: the 2009/2019 MAT New Stratos.

In 2009, a prototype was completed using the Ferrari 430 Scuderia as its base but after its initial success Ferrari refused to supply parts and the project was canned.

In 2019, Manufattura Automobili Torino (MAT) started it up again by using customer-supplied Ferraris. Although it uses Ferrari's 4.3-litre V8 engine, the engine produces 27kW more power in the New Stratos, wand being 50kg lighter.

With only 3000kms on the clock, this example is Number 1 of 25 and is expected to fetch up to AUD$1.5 million.