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· Registered
16,301 Posts
I made a thread about this a while before the crash, Ive collected some info on it

a good article for those of you who know french

prototype vert

Heres some other rare 8 series stuff from different tuners

I had another really good article on the M8 in english but its lost in an unorganized picture folder somewhere on my HD

· Registered
9,045 Posts
it never sold though. bmw decided to keep it from the streets, so it remained a concept car and museum star and its engine went into the mclaren f1.
Actually the final portion of your comment is not factual. It gets somewhat confusing, but try to follow paying close attention to each engine's specific name in bold to make things more clear.

The standard 850i and 750i/iL BMW models used the M70 engine. It was a 5.0L V12 with one camshaft per cylinder bank and 24 valves that made around 300hp and was used from late 1989 until 1993. Later on in 1994 they would increase the displacement of the M70 to 5.4L creating the M73 which offered 326hp, at the same time changing the name of the car to the 850Ci. The M73 became the standard V12 engine until 1999 when 850 production finally ended.

From the original M70 BMW Motorsport developed the S70/1 in 1990 which they only built one of. It was close to 6.0L in displacement, had two cams per bank, with 48 valves total and reportedly made close to 550hp. This single engine was developed for the BMW M8 concept which never saw production.

In 1992 BMW also began offering the 850CSi which carried the S70 engine. It was essentially a single cam version of the S70/1, with 24 valves and a reduction from ~6.0L down to 5.6L. This engine was good for 380hp.

Backing up a little, the story goes that Gordon Murray's old friend Paul Rosche, chief engineer at BMW Motorsport, approached him in 1990 at the Hockenheim Grand Prix to inquire about the engine plans for McLaren's sports car project. At the time Murray still had not found a suitable powerplant for the F1 and he knew he was running out of time. Rosche offered up that his group could build the engine for the F1. It was at that time Rosche mentioned the 48V version of the 850's V12 (S70/1) that they had been developing which he thought would suit Murray's needs.

Quoting from "Driving Ambition":

On October 25th, 1990, Gordon visited Munich. The hopped up production V12 would not do: "Too big and heavy. Definitely not for us. Then Paul asked 'What do you really want?', so I told him: big displacement in the smallest possible package-size -- absolutley no more than 600mm long -- revving to around seven-five -- 550-plus bhp -- maximum weight 250kg -- rigid enough to work as a load-bearing structural member -- dry-sump lubrication to minimize overall height and avoid surge in high-G cornering.

And Paul simply said 'We'll do a new engine'."

Gordon had instructed the team of Motorsport engineers that power-to-weight was the bottom line and to consider that in everything that they did. "Never use a 10mm bolt when 9mm would do - consider weight as driving the design." He could see them obviously thinking 'who is this loony, telling us how to design engines?' but Paul Rosche backed him up.

The final engine that Motorsport developed out performed McLaren's 550hp target by 14 percent at 627hp. It met the 600mm length requirement, but with all necessary ancillaries, exhaust system and silencer it overshot the weight target by about 16kg. Gordon would forgive them that - 6.4 percent overweight was more than compensated for by 14 percent extra power of course. The first completed S70/2 V12 was delivered to McLaren for fitment to one of their test mules March 4th 1992.
The really exciting thing about seeing these M8 photos is that previously it had been rumored that BMW had crushed the M8 concept car. It is great to see that was not true and that it still exists. :cool:

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