BMW M’s only mid-engined machine was designed first and foremost as a race car, but it was devastatingly effective on the road, too

BMW must have been a wonderful place to work in the mid-1970s. The near bankruptcy the company faced at the end of the 1950s was long forgotten and its new 5-series and 3-series models were selling well on the back of abundant critical acclaim. The soon to be announced 6- and 7-series models would further enhance the marque’s model line up.  

Then there was BMW’s recently formed Motorsport department headed up by Jochen Neerpasch that had seen the CSL ‘Batmobile’ coupes win titles around the globe and had an exciting road car program planned. But what Neerpasch really wanted was a full-on racer with which BMW Motorsport could take on arch-rival Porsche in Group 5 racing. Thus the M1 was born. 

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BMW didn’t have the production capacity to make the required number of cars in Munich in order to gain homologation so it commissioned Lamborghini to design the chassis and assemble the car. Neerpasch dictated that the car was to be mid-engined – a first for BMW – and its powerplant was to be a 3.5-litre straight-six. 

As you can read in the history section below, Lamborghini let the side down as far as producing the cars was concerned and by the time BMW could make alternative arrangements, the requirements for Group 5 homologation had changed. The road car finally saw the light of day in early 1979 and was universally acclaimed as a remarkable achievement. It was BMW’s first, and until the arrival of the i8, its only mid-engined machine. It was also the first BMW road car to feature a four-valve-per-cylinder layout and this engine went on to power two generations of M5 as well as the M635CSi coupe. 

History

Knowing that BMW Motorsport didn’t have the capacity to hand-build the 400 cars required for Group 5 homologation the then boss and driving force behind the M1, Jochen Neerpasch, commissioned Lamborghini to design and build the chassis and assemble the car. Lamborghini’s Gianpaolo Dallara might have done a superb job of designing the chassis, but it soon became clear that the company he worked for wasn’t going to be capable of producing the car in sufficient numbers. With rumours of impending financial collapse at Sant’Agata, BMW pulled the plug on Lamborghini’s involvement in the project. 

Thus the M1’s production turned into one of the most complex of all time. The glassfibre body was designed by Giorgetto Giugiaro of Ital design, and was produced by Trasformazione Italiana Resina, based just outside Modena. The Lamborghini-designed space-frame chassis was produced by another Italian firm, Marchesi, also in Modena, while Ital Design in Turin bonded the elegant panels to the space-frame, fitted the glass, painted the complete body/chassis units and fitted the dash and some interior and electrical parts. 

These part-completed M1s were then shipped to specialist manufacturer, Baur, in Germany for the installation of engines that were hand-built by BMW in Munich, transmissions from ZF, and all the remaining interior trim. The complete vehicles were then shipped to Munich so that BMW Motorsport could, in theory, give each car a final tune, wheel alignment check and road test before packing it off to the lucky customer. The reality was that a significant amount of work was required on the M1s once they rolled back into BMW’s Motorsport department as the build quality from Ital and Baur just wasn’t deemed acceptable.

The main upshot of this disastrous production process was that by the time production of the M1 got into its stride, the requirements for Group 5 homologation had changed and this left the M1 all dressed up with nowhere to go… which lead to the Procar series. This acted as support show to the F1 circus and pitched leading F1 drivers against endurance and touring car aces in 470bhp Group 4 M1s. Niki Lauda won the inaugural championship in 1979 with Nelson Piquet taking the title in 1980.

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The M1 also took to the track at endurance races such as the 24 Hours of Le Mans where it was campaigned from 1980 until 1986 with various rates of success, but in truth it was outdated and even when packing a turbocharged version of its straight-six pushing out 633kW in Group 5 guise it wasn’t wholly competitive.

Engine and Transmission

The M1’s raison d’être was to go racing so BMW wasn’t too concerned that it was going to lack a 12-cylinder engined favoured by contemporary supercar rivals. Its 3453cc M88/1 straight-six was the work of BMW’s engine guru, Paul Rosche, who also oversaw the company’s F2 successes in the 1970s as well as being responsible for the E30 M3’s S14 four-pot, BMW’s turbocharged F1 unit and the McLaren F1’s S70/3 V12. All told, not a bad resumé.

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