GM is certainly no stranger to V8 engines, but interestingly, The General chose to shelve Saab’s little-known V8 engineering project after GM acquired a 50 percent stake in the company in 1989.
As reported by The Autopianthe story begins with the Saab 9000 in the early 1980s as part of the Type Four platform collaboration between Saab, Fiat, Lancia and Alfa Romeo. With the shared architecture as a starting point, Saab undertook extensive re-engineering of the vehicle to meet its own standards, particularly with regard to structural rigidity and US safety compliance. The company also adapted its traditional engineering approach to accommodate a transverse engine layout.
As development progressed, company leaders in the US proposed adding a V8 engine to strengthen the car’s appeal in the American market. Although the core engineering team remained committed to turbocharged four-cylinder engines, a small group in Finland started a secret project in 1988 to explore the V8 idea further.
Dubbed the “Twin Four,” this engine combines two Saab inline-four engines into one 4.0L V8 arranged at a 90-degree angle. Engineers reused as many existing components as possible, creating a naturally aspirated unit that produces around 230 horsepower. The engine was paired with a five-speed manual transmission and was installed on the Saab 9000 CD prototype in 1989.
Testing was extensive, with the vehicle covering approximately 65,000 kilometers in various conditions. Internal evaluations indicated that the concept was feasible for production and could support meaningful volumes, but this was not the case.
Around the same time, Saab underwent major corporate changes, forming Saab Automobile AB with GM acquiring a 50 percent stake. When the V8-powered prototype was introduced, GM expressed interest in expanding engine offerings but ultimately preferred to use its own V6 engine rather than adopt the new in-house V8.
As a result, the Twin Four project was never approved for production, and although several prototype machines were built, only one complete vehicle was assembled, which can now be found in the Uusikaupunki factory museum in Finland, amazingly still in running condition.
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