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      02-03-2017, 02:09 AM   #1
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The M10: BMW's most successful engine.

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A little write-up From yours truly with sources from different articles. Last few paragraphs of the M12 coming from GT Spirit, and the S70/2 part from Wikipedia.: http://gtspirit.com/2014/05/31/the-m...l-f1-car-ever/.


The most powerful engine ever used in Formula one was the legendary BMW M12/13 1.5 litre turbo inline-4 developing upwards of 1,400 hp (no it's not a typo!) in qualifying specs. The engine was then detuned to around 850 hp for the race. This engine allowed Nelson Piquet to win the 1983 Formula One World Championship in his beautiful Brabram BT52. It is the only Formula One world championship that BMW won as an engine supplier, the company never won the title as a manufacturer (BMW Sauber Team).

But, did you know that Formula one's mightiest engine ever has its block from a humble 1960's "Neue Klasse" sedan?? This engine, codenamed M10, was probably BMW's most important power plant ever because it was produced in its different configurations, until 1988, an incredible lifespan of 27 years! It was also the basis for the famous "S" 4 and 6 cylinder engines of the M cars from the E26 M1 to the E46 M3!


Genesis of the M10 engine:
The M10 (named in its first iteration M115, where the 15 meant 1.5 litres) started its life as an was an iron block 1,5 litre SOHC 8-valve designed for BMW by Baron Alex von Falkenhausen and was conceived to be an engine that suited a large variety of applications carrying with it a very long shelf life. Fitted in the humble BMW 1500 and packing all of 72hp (then 80hp) at 5,700 rpm. The M10 then had more than 3.5 million units produced making it one of the longest serving engine blocks ever created. Some of its iteration were legendary, such as the M31 of 1973-74, enlarged to 1.9 litres with a turbocharger and developing 168hp @ 5,800 rpm and 181 lb ft. @ 4,000 rpm. That engine equipped the famous 2002 Turbo, BMW's first ever production turbocharged car.

M10 Engine
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The ingenuity behind the block was that, from a starting capacity of 1499cc, it was cast within tolerances that allowed it to be bored out to capacities of up to 1990cc thus making it a very flexible unit, useful in a wide variety of chassis including a large array of specifications for the 1500, 1600, 2002, 3 series and 5 series BMW’s of the 60’s, 70’s and 80’s. The M10 made it all the way from the BMW 1500 of 1961 to the 318i E30 of 1985-88 before being discontinued (codename: M10B18).

M31 version of the M10, 2002 Turbo engine:
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The M12/13 Formula One engine:
Now, let's talk about what's probably the most amazingly insane version of the M10 engine: the incredible turbocharged 1.9 litre inline-4 M12/13 that won them their only Formula One world championship. Turbocharged engines in Formula One were pioneered by Renault in 1977, and eventually the French proved this was the way to go in F1 as they created superior power and torque than their normally aspirated competition. Although Renault didn't win either the manufacturer's or driver's world championships, their cars proved to be so quick that other teams decided to follow the turbocharging way. Ferrari launched their turbo engine in 1981, followed by Brabram (with the famous BMW engine in 1982, Alfa Romeo in 1983 and Honda, Porsche (under the TAG-banner), Ford-Cosworth followed suit in 1984. Eventually all teams had turbocharged engines and, over the years, their power grew and grew — up to the point of insanity for the pure joy of formula one fans.

Going back to BMW, in August of 1980, they decided to embark on an audacious all-out attack for the 1981 Formula 1 World Championship. How did it happen? Bernie Ecclestone, wasn't the guru of Formula One then, but was the owner of struggling team Brabram. He, however had an ace in his cards: the talented engineer/designer Gordon Murray (the father of the future McLaren F1). Also, relationships were started at BMW as early as 1979 when Niki Lauda was still driving for Brabram and they were unhappy about the performance of their Alfa Romeo engines. Eventually Lauda left for McLaren, but Bernie Ecclestone saw the great potential of turbocharged engines and convinced BMW to supply them with such an engine.

Not that the Bavarians needed much convincing because they were already racing and winning in the lower spheres of single-seaters. After returning with great success to touring car racing and with the creation of the Motorsport division, BMW was thinking more and more of competing with the big boys: Formula racing. Baron von Falkenhausen, the designer of the M10 and Paul Rosche, the future engine guru, were behind this push for motorsport. With new regulations in Formula 2 allowing for 1.6 litre displacement, BMW had a perfect engine for the series: the M10, a radial four-valve cylinder head designed by Ludwig Apfelbeck to make it produce 200hp, and subsequent versions followed afterwards. BMW eventually supplied engines to the championship-winning drivers in 1973, 1974, 1975, 1978, 1979, and 1982. Talk about total domination in F2!

Radial Valve Version of the M10 racing engine:
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M12 DOHC 2 16 valve liter version of the M10 engine for F2
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Paul Rosche eventually became the Technical Head of BMW Motorsport in 1975 and he was instrumental with Bernie Ecclestone and BMW new Sporting Director Dieter Stappert to convince the board to take the plunge into Formula One.

Enter the M12/13 engine, a turbocharged 1.5-liter inline four-cylinder engine fitted with KKK turbocharger and a Bosch digital electronic management system. Its block of course came from the now well-proven M10 already used and winning in various racing series and cars like the BMW 2002 and the 3 Series.

M12/13 1.5 Liter Turbo Formula One engine:
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Instead of casting new blocks for their turbocharged F1 project, BMW only used old ones to that had done more than 100.000 kilometres. The idea was that all the stresses of the casting process would have been sorted out: if an engine block would break, it would have done so already. Or as Paul Rosche, who was in charge of BMW’s racing engine department, said about these blocks: “They are like well-hung meat.”

Even more remarkable was the process to strengthen the block’s composition. Not only were the blocks kept out in the cold and rain, but it’s also rumoured that they were peed on by the engineers. As strange as it may seem, urine has a nitriding effect as it contains compounds which form hard crystals on the surface of metal. Sword makers in the Middle Ages discovered that steel blades quenched in urine were harder than those that weren’t.



Formula One most powerful engine ever!

BMW’s turbocharged M12/13 engine made its F1 debut with the Brabham team in 1982. The four-cylinder engine provided 850 horsepower in qualifying trim, but was detuned to around 640 horses for the races in order to save fuel. BMW’s debut as engine supplier wasn’t an initial success. There were some issues with the reliability and Brabham-driver Nelson Piquet even failed to qualify for the American Grand Prix in Detroit. But the next race in Montreal, with its long straights and high speeds, the BMW engine proved itself and Piquet was victorious. Eventually more success came and in 1983 Piquet became the first World Champion with a turbocharged car. BMW had made history at the top echelon of racing!

World Championship winning Brabram BT52 Formula One
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The following two years two other teams (ATS and Arrows) were powered by BMW as well, but none of the three teams were successful in beating the strong Porsche-powered McLarens. In fact, the partnership with ATS was abandoned within a year as the team proved to be quite a failure. For the 1986 season BMW started to supply engines for the new Benetton team, in addition to Brabham and Arrows. The Benetton B186 driven by Teo Fabi and Gerhard Berger would prove to be the most successful BMW-powered team as Arrows remained uncompetitive and Brabham’s radical BT55 failed to live up the expectations.

The amount of power provided by the BMW engine almost doubled since its debut. In 1986, the thirsty BMW M12/13 engine was in during the race limited to 850 horsepower, but in qualifying trim the turbo boost was maximized as far as possible. Everything was tried to get more power from the engine. For instance, the waste gate was sealed shut and within three laps the engine was gone. The exact amount of power delivered by the Bavarian four-cylinder was unknown, but according to Rosche: “It must have been around 1,400 horsepower; we don’t know for sure because the dyno didn’t go beyond 1,280 horsepower.”

Insanity is perhaps the best word to describe the F1 cars of 1986, when the race for more power peaked. Naturally aspirated engines were banned while the turbocharged engines were unrestricted. There were no rules regarding the amount of power or number of engines used. The only rule that put some limitations on performance was that the amount of usable fuel was limited at 195 litres. But since this only applied for the race, and not for qualifying, the result was as predictable as insane.

For qualifying, the BMW engine ran with 5.5 bars of boost. The power unit was paired with an equally short-lived gearbox that could withstand the engine’s tremendous power and tires that would also last only a few of laps, just enough to qualify. In those days, a F1 driver had only one lap to set a time, before his engine was turned into a molten lump of metal, or the gearbox disintegrated, or the tires burst — durability was clearly not an issue. In an interview with Atlas F1 Gerhard Berger told about the insanity of qualifying:

"THEN ON TOP OF IT YOU HAD THE QUALIFYING. YOU HAVE TO REMEMBER BACK THEN, YOU HAD A QUALIFYING LAP, WITH QUALIFYING TURBO, WITH QUALIFYING TIRES. YOU WOULD COME TO THE MORNING TO PRACTICE, BUT ALL YOU COULD PRACTICE WITH WAS A CERTAIN AMOUNT OF BOOST, YOU WOULD HAVE ABOUT 900 OR 1,000 HORSEPOWER, BUT IN THE AFTERNOON YOU WOULD HAVE AROUND 1,400 HORSEPOWER. SO IN THE AFTERNOON YOU HAD A DIFFERENT GEARBOX, BECAUSE OVER LUNCHTIME THEY WOULD CHANGE THE GEARS, AND THEN YOU WOULD PUT ON ONE OF THOSE ONE LAP SPECIAL TIRES AND YOU WOULD GO OUT WITH ALL THAT EXTRA POWER AND THEN THE WHOLE LAP WAS A COMPLETE COMPROMISE, BECAUSE ALL YOUR BRAKING POINTS WERE AT DIFFERENT POINTS BECAUSE OF THE EXTRA POWER AND SPEED. AND OF COURSE OFTEN THEY WOULD CHANGE THE BRAKES AS WELL, SO YOU JUST HAD TO REACT ALL THE TIME TO THE CHANGING SITUATION. AT THE END, WHOEVER DID THE BEST COMPROMISE WAS AHEAD. BUT IT WAS A VERY SPECIAL ERA AND VERY VERY EXCITING FOR THE DRIVER AND FOR SURE YOU NEEDED BIG BALLS."

The turbo engines of those days came with very poor power delivery characteristics. Especially the BMW suffered from poor throttle response and subsequent turbo lag. In an interview with the Autosport magazine, Berger said:

"THE CAR WAS LIKE A BOMB AT CIRCUITS LIKE SPA, AUSTRIA AND MONZA. AND THE POWER WAS UNBELIEVABLE — EVEN IF THE TURBO DELAY WAS TERRIBLE. YOU’D OPEN THE THROTTLE AT THE ENTRY TO THE CORNER ONLY TO GET THE POWER AT THE EXIT. AND IF YOU MISSED IT BY FIVE OR 10 METRES, THERE WAS NOTHING YOU COULD DO — YOU JUST SPUN IT. THE LAG WAS ABOUT ONE OR TWO SECONDS. AT ZELTWEG, DOWN THE LONG STRAIGHT TO THE BOSCH KURVE, THE CAR WAS THROWING OUT 1400 HORSEPOWER AND JUST KEPT ON PUSHING — YOU FELT LIKE YOU WERE SITTING ON A ROCKET."

Gehrard Berger Benneton B186 Formula One
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And what a rocket the Benetton-BMW was! Teo Fabi drove his Benetton at Zeltweg in Austria to pole position with an average speed of 256.03 km/h. At Monza in Italy Gerhard Berger was clocked with a top speed of 352.22 km/h, while Fabi passed the straight with 349.85 km/h. The five fastest cars through the speed trap were all powered by BMW. At the Mexican GP, Berger reported wheel spin in 6th gear at 345 km/h. The race in Mexico was the first win for Berger and the first win for the Benetton team, but it also was the last win for a turbocharged BMW engine. At the company’s headquarters in Munich the men in suits had decided to pull the plug on the F1 project.

The era of unlimited turbo power came to an end. Normally aspirated engines returned to F1 in 1987, while turbo engines were restricted by tighter fuel limits and boost restrictions, before they were banned altogether at the end of 1988. One of the reasons why the turbos were banned from F1 was that the cars were getting too fast!


Link between the M10 and BMW's famous "S" series engines of their M cars:

There is a direct link between the M10 and the S series engines of M cars. The S14 engine equipping the E30 M3 in fact used the M10 block and the E26 M1's M88 inline 6 cylinder head design. The M88 itself can be considered as the 1st generation of M engine and it had several evolutions: M88/3 equipped the E28 M5 and E24 M635 Csi. The S38 engine is the development of the M88 and was fitted to various M cars until 1996. Going back to the M88, it was itself based on the M49 motorsport engine of the E9 3.0 CSL. That M49 engine is based on the M20/M30 inline-6 that were using the same design principle as the... M10! Both engines has a 30-degree cam to the right for a lower profile, a crossflow head and a gas flow head in later models design, and a chain-driven single overhead cam with rocker arm valve actuation. Further similarities include a cast-iron block with an aluminium head and a forged crankshaft. Now that's what we call going full circle!

The S14 engine used in the 1st generation M3:
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The amazing dry sump M88 engine of the E26 M1
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The engine that symbolises BMW: the M20/30 inline 6
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A Nice chart from EVO about the M10 and its derivatives
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Great videos on the history of the M10 and M12/3 F1 Turbo engine




Dyno run of the M12/3 F1 Turbo engine and incredible glowing headers



Fantastic BMW video of the assembly of the M12/13 engine and Brabram BT52 F1 car (with Paul Rosche)



Qualifying lap of the Benetton B186 driven by Gehrard Berger




Side Note: The BMW S70/2 V12 engine of the 1991-98 McLaren F1
- From Wikipedia. I can assume that if not for the M10 engine, the S70/2 engine would never have seen light of day!

The incredible 6.1 litre S70/2 V12 engine of the McLaren F1
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Gordon Murray, who had previously worked with Paul Rosche during their time at Brabham in the early 1980s, met him again after the 1990 German Grand Prix. When his plans to develop an engine with Honda fell through, Murray turned to Rosche and BMW Motorsport for their services. Paul Rosche then designed and built Murray a 6.1 L (6,064 cc) 60-degree V12 engine called the BMW S70/2.[13] At 627 PS (461 kW; 618 hp) and 266 kg (586 lb) the BMW engine ended up 14% more powerful and 16 kg (35 lb) heavier than Gordon Murray's original specifications, with the same block length. It has an aluminium alloy block and heads, with 86 mm (3.4 in) x 87 mm (3.4 in) bore/stroke, quad overhead camshafts with VANOS variable valve-timing (a relatively new and unproven technology for the time) for maximum flexibility of control over the four valves per cylinder, and a chain drive for the camshafts for maximum reliability. The engine uses a dry sump oil lubrication system. The carbon fibre body panels and monocoque required significant heat insulation in the engine compartment, so Murray's solution was to line the engine bay with a highly efficient heat-reflector: gold foil. Approximately 16 g (0.8 ounce) of gold was used in each car. The road version used a compression ratio of 11:1 to produce 627 hp (468 kW; 636 PS) at 7400 rpm and torque output of 480 lb·ft (651 N·m) at 5600 rpm. The engine has a redline rev limiter set at 7500 rpm. In contrast to raw engine power, a car's power-to-weight ratio is a better method of quantifying acceleration performance than the peak output of the vehicle's powerplant. The standard F1 achieves 550 hp/ton (403 kW/tonne), or just 3.6 lb/hp. The cam carriers, covers, oil sump, dry sump, and housings for the camshaft control are made of magnesium castings. The intake control features twelve individual butterfly valves and the exhaust system has four Inconel catalysts with individual Lambda-Sondion controls. The camshafts are continuously variable for increased performance, using a system very closely based on BMW's VANOS variable timing system for the BMW M3; it is a hydraulically actuated phasing mechanism which retards the inlet cam relative to the exhaust cam at low revs, which reduces the valve overlap and provides for increased idle stability and increased low-speed torque. At higher rpm the valve overlap is increased by computer control to 42 degrees (compare 25 degrees on the M3) for increased airflow into the cylinders and thus increased performance. To allow the fuel to atomise fully, the engine uses two Lucas injectors per cylinder, with the first injector located close to the inlet valve – operating at low engine rpm – while the second is located higher up the inlet tract – operating at higher rpm. The dynamic transition between the two devices is controlled by the engine computer. Each cylinder has its own miniature ignition coil. The closed-loop fuel injection is sequential. The engine has no knock sensor as the predicted combustion conditions would not cause this to be a problem. The pistons are forged in aluminium. Every cylinder bore has a nikasil coating giving it a high degree of wear resistance. From 1998 to 2000, the Le Mans–winning BMW V12 LMR sports car used a similar S70/2 engine. The engine was given a short development time, causing the BMW design team to use only trusted technology from prior design and implementation experience. The engine does not use titanium valves or connecting rods. Variable intake geometry was considered but rejected on grounds of unnecessary complication. As for fuel consumption, the engine achieves on average 15.2 mpg (15 L/100 km), at worst 9.3 mpg (25 L/100 km) and at best 23.4 mpg (10 L/100 km).
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