1990, V12 (S70/1), about 6.0l displacement, 550 hp, prototype, number: 1
The BMW 850CSi is a detuned version of the M8 which has never been produced and remained a prototype only. The M8 should have been built in a consequently lightweight manner in order to be a 'Ferrari-Killer'. The specially developed 550 hp engine has never been used except in the prototype - of which only one exists. But with the support of McLaren the M8 engine was transformed into the power plant of the McLaren F1 super sports car. At the time of development of the M8 there was virtually no market for such a car, so the BMW manager cancelled the project.
The M8-Prototype is perhaps the best-kept secret of BMW. Absolutely no one must see it or can get information, by order from the general manager himself. Questions from motorsport magazines remain unanswered as well. The car is locked away in the so-called Giftschrank, which could be translated as 'poison-storage'. According to BMW it is hidden behind lots of boxes anyway and will be destroyed in the near future as the 8 series doesn't exist any more and neither a successor.
The Prototype has never been road safe (even the headlights were missing as you can see in the picture) and was only loosely patched together, which is the reason why it is not presented in their museum. It's not even good for that ...says BMW.
Yes, the papers of an 850CSi say, it's an M8, but that's not of much use if you know what it could have been. What the S70 engine is capable of speaks for itself. See the world record run of the McLaren F1. The guys at McLaren say they could get 1000 hp at 9500 or 10000 rpm from the engine.
The different versions of the S70 engine:
S70 5576 ccm 380 hp, 24V, 850CSi 1992
S70/1 about 6000 ccm 550 hp, 48V(?), M8 prototype 1990
S70/2 6064 ccm 627 hp, 48V, McLaren F1 1993
S70/3 6064 ccm 635 hp, 48V, McLaren F1 1996