BY ANTHONY TOIGO
The M1 BMW – It’s still that great. Jochen Neerpasch’s BMW Motorsports team was dead right about the potential of this iconic street-legal racer.
10. The M1 Team – BMW Motorsports Wanted More Wins After Their Impressive 3.0 CSL Long Winning Streak
What makes the M1 unusual is how racing design and know-how also made it into the street-legal version. BMW Motorsports gained extensive experience winning races from the late 1960s until the mid-1970s. The 3.0 CSL effort provided a solid foundation of experience and know-how under the skillful guidance of Jochen Neerpasch. He’d intended the M1 to be a race car first.
Neerpasch brought everything forward into the M1 design strategy and was committed to continuing the winning streak. To homologate the M1 using a silhouette car strategy, they had to build 400 sellable units. The remaining balance of cars – was 60 for racing and other purposes. The car is still an amazing ride – even after 47+ years. Whenever you see a BMW M1 for sale, the comments carry the same message, “it’s one of my all-time favorites”. Lucky are the few who have an M1 in their garage, or those who’ve driven one.
9. The M1 body concept in form came from an original idea in 1972
Paul Bracq was BMW’s chief designer while the BMW Motorsports division was winning big with the 3.0 CSL. Bracq came up with the idea to create something new and forward-thinking that wasn’t intended for racing. He conceived and drew up plans for the BMW Turbo, then built it into a working prototype in 72. The Platform used the body pan, and many components from the 2002 Turbo including the engine and transmission – mounted transversely and mid-ship behind the driver.
Bracq and his design team performed extensive wind tunnel testing on the new body while recording the impressive data from their innovation. The completed car was a hit and received much positive attention at the Paris Motor Show… it also performed well when driven – so much so that It was BMW’s best performer at the time. Neerpasch recognized the data’s value and knew Bracq had created a winning design that significantly reduced wind resistance. The body design was chosen as a baseline for the M1 in 1975.
8. The M1’s Fuel Delivery – Race Proven Kugelfischer Mechanical Injection
Part of the original 3.0 CSL racing effort employed the Kugelfischer fuel injection system. It could be mapped and dialed in very precisely for almost any circumstance. Originally designed for diesel applications, it adapted well to high-performance gas and racing engines. Before digital motor electronics (DME Motronics) technology came about in the early 1980s, Kugelfischer injection was the best of breed – mappable system. Ultra-fine fuel atomization precisely fed the M1’s thirst via this system for increased power well above any carburetor.
The BMW Turbo car with Kugelfischer injection produced a turbocharged – 280 horsepower in a 2- liter 4-cylinder engine with a single cam and 2 valves per cylinder. A new cylinder head design using twin cams and 4 valves per cylinder easily gave the M1 six cylinder street version its de-tuned 277 horsepower. BMW Procar tuned? Try 470 horsepower… and in 1981, the Schnitzer turbocharged M1… up to 1000 horsepower. Great engineering, right?
7. Effective Power To Weight – The M1 Can Drift, Just Ask – It Delivers
The Kugelfischer injected BMW 2002 Tii assisted the epitomized example of what a favorable power/weight ratio can do for performance. The Tii couldn’t disappoint. Neither does the M1 applying the same concept – sticking with the basic principle that proper power to weight makes for a king of performance. 277 horsepower in an aerospace tube frame chassis with fiberglass body kept the street-destined M1 light at 2866 Lbs.
Performance wise? The de-tuned street M1 can be easily coaxed into a drift on dry pavement. The overall experience – the car doesn’t surprise you in unwanted ways. It’s drivable, forgiving, and wants to be driven. The street version 0-60 @ 5.4 seconds – procar race version – 3.5 seconds.
Since the M1, M Series BMW cars can’t use the Kugelfischer system due to a lacking ability to meet emission standards – the same held true when the M1 was introduced. The full production M3, M5, and M6 introduced in the later 1980s, all utilized DME Motronic systems. The same BMW M1 M88 Engine was used in the M5 & M6. Today, we have the best of all things with engine management – direct high-pressure injection that’s precisely monitored and adjusted for optimal performance has been added to improve performance even further.
6. A Group 5 Vision With BMW Turbo Wind Tunnel Data – Add Turbocharging
The BMW Turbo produced up to 280 horsepower, but the decision was made to tone it down to a still respectable 200. The same powerplant was first used in the short-lived BMW 2002 Turbo. The 2002 Turbo was restricted to 170 horsepower. It didn’t disappoint. All the experience and recorded data during earlier development would become valuable for the moment when the decision was made to re-look at the BMW Turbo – now as a base platform for the M1.
The wind tunnel data suggested the wedge design would give the car a solid advantage on the racetrack via wind drag reduction. When Giorgio Giugiaro began to design the M1 body in 1975, the spec was set to stick with and improve on the original design of the BMW Turbo. The result produced a car that looked almost identical to the Turbo with only minor differences in wind drag.
5. Developing the BMW Turbo Concept Into A Race Car For The Street Was Decided, But to Homologate The M1 Proved Challenging
When the 3.0 CSL racing platform was reaching obsolescence – under Neerpasch, the idea was suggested to dust off the BMW Turbo plans and consider a redesign using an inline 6-cylinder 3.5- liter mid-engine and transaxle to propel the concept racecar. (Neerpasch knew of F1 cars proven mid-engine layout and wanted to employ the concept in the M1). BMW Motorsports contracted Lamborghini to build the cars.
Engaged successfully, but Lamborghini’s financial woes delayed the production of the M1 by over two years. Eventually, the delay would doom Neerpasch’s efforts when the M1 would become obsolete for racing and the corporate checkbook restricted. Regardless, the reality of what race fans wanted to see perform on the track was shifting back toward Prototypes. The delay and shift in spectator trends compounded against the BMW Motorsports division’s best efforts.
4. Lamborghini’s Troubles Launched A New Automotive Engineering Company To Finish the M1 Design
The delays caused by Lamborghini’s financial woes were costly but didn’t kill the effort. A group of engineers at Lamborghini that worked on the M1 project formed a new design company called Italengineering – then completed the plans. The steel frame was designed by Gianpaolo Dallara, the fiberglass body by Giorgio Giugaro. The engine design took place in-house at BMW headed by brilliant designer Paul Rosche.
Despite the best efforts employed by the Motorsports division, the delay was unavoidable. The first hand-built M1 was completed in 1978. The delay kept the effort back in Group 4 instead of the Group 5 target. They were gunning for Porsche’s 935 Group 5 effort by then but could only regroup and get the job done. All aspects guided by Neerpasch going into the design of the M1 were best of breed. The M1 was designed and built to win races. Opportunity would have to wait.
3. Let it Breathe – Preparation for The Turbo Charged Group 5 M1 Run
Paul Roche’s 3.5 liter M88 engine design was built in-house by BMW initially for the M1, then later the basis for the M5 & M6 up to 1989. The cylinder head design’s more recent applied concept can be traced back most notably to Cosworth F1 engines and Ford. The application of twin camshaft engines employing 4 valves per cylinder wasn’t a new idea though.
Peugeot is credited with the first 4 valve twin cam head in 1912 led by designer Ernest Henry. The principle – four smaller valves allow more area and volume flow than two larger valves for the given combustion chamber area. Simple and effective. Also, two camshafts allow for easier/greater tuning variations over a single cam. The four-valve head provided greater upside power potential, especially when adding turbocharging.
2. ZF vs Hewland Transaxles – Higher Power Input and Better Balance From The Hewland
The approximate 40 M1’s built to meet Procar specs, like their street-destined version were fitted with the standard ZF transaxle. The ZF was rated good to handle up to 470 horsepower. But, in order to avail the full potential from the M1, say like pumping 900+ turbocharged horsepower to the input shaft, you’d have to replace the ZF with a Hewland gearbox designed with dog ring selectors for racing… but no synchro mesh. The added benefit of using the Hewland would be better overall shifting control from the dog ring design.
If you were ever lucky enough to find an extremely rare Group 5 M1 with a Hewland gearbox, you’d have to employ heal–toe footwork for downshifting though, sorry, no synchros (they only get in the way anyway) or paddles. But, the learning curve makes it well worth the effort because the technique helps keep the car better balanced on corner entry while helping lower lap times. Heel- toe downshifting is an art form kinda like modern-day multi-tasking on steroids – when done correctly, just makes the car even faster. Need a Hewland or similar for best results.
1. Putting it all together – Germany 1981 – Was The M1 Was Past Its Prime?
Everybody thought the M1 was outdated – So, Schnitzer prepped an M1 to be driven by Hans-Joachim Stuck that proved it was a winner all along – the design was still relevant. The Schnitzer team thought the M1 would be the perfect platform to transition their program to. BMW and Neerpasch didn’t make any missteps during the design and strategy process while putting the M1 program together. Rule changes and unforeseen delays in outsourcing with Lamborghini were beyond the team’s control. All that would unfortunately doom the M1 from having more deserved moments on the podium.
Despite all the complications, when Schnitzer applied their turbocharging magic that the M1 engine was designed to work with – the results were as hoped and expected. Driver Hans-Joachim Stuck put the car on the podium on the second outing at Salzburgring. Their third try at Norisring – the M1 showed what it was built to do with first place against Porsche’s 935 and Ford’s winning Capri. It would seem mission accomplished, right? Just under the wire before rule changes would render Group 5 Obsolete.
A month after I published this article, I came across this youtube video that provides additional/different perspective. Enjoy!