The BMW M78 is a straight-six OHV piston engine. It is the first straight-six automobile engine produced by BMW. The engine initially had the same bore and stroke as the four cylinder engine from the BMW 3/20; the bore spacing was increased to allow for further increases in bore and to provide for more crankshaft bearings. The engine was designed by Fritz Fiedler.

Manufacturer	BMW
Production	1933 – 1950
Predecessor	none
Successor	BMW M337
Configuration	straight-6

Models

Model	Displacement	Power	Torque	Redline	Year
303 version	1,182 cc	22 kW (30 PS; 30 hp)	68 Nm (50 lbft)		1933-1934
315 version	1,389 cc	25 kW (34 PS; 34 hp)			1934-1937
315/1 version	1,389 cc	30 kW (41 PS; 40 hp)			1934-1937
319 version	1,911 cc	34 kW (46 PS; 46 hp)			1935-1937
319/1 version	1,911 cc	41 kW (56 PS; 55 hp)			1935-1937
326 version	1,971 cc	37 kW (50 PS; 50 hp)			1936-1950
320 version	1,971 cc	34 kW (46 PS; 46 hp)			1937-1938
327 version	1,971 cc	41 kW (56 PS; 55 hp)			1937-1953

M78 (303 version)

This first version of the M78 used a bore of 56 mm (2.2 in) and a stroke of 80 mm (3.1 in), with a compression ratio of 5.6:1. It produced 22 kW (30 PS; 30 hp) at 4000 rpm and 68 Nm (at unknown rpm).
Applications:

• 1933-1934 303

M78 (315 version)

A development of the 303 version, where the bore was increased from 56 mm (2.2 in) to 58 mm (2.3 in) and the stroke was increased from 80 mm (3.1 in) to 94 mm (3.7 in). The compression ratio remained at 5.6:1. This engine produced 25 kW (34 PS; 34 hp) at 4000 rpm.
Applications:

• 1934-1937 315

M78 (315/1 version)

An upgraded version of the 315 engine with the compression ratio increased to 6.8:1 and using three Solex carburetors. This version produces 30 kW (41 PS; 40 hp) at 4000 rpm.
Applications

• 1934-1937 315/1

M78 (319 version)

The 315 engine was enlarged to 1911 cc for the 319. This was a result of increasing the bore to 65 mm (2.6 in) and the stroke to 96 mm (3.8 in). This engine produced 45 bhp (34 kW) at 3750 rpm.
Applications:

• 1935-1937 319
• 1937 329

M78 (319/1 version)

The 315/1 engine was enlarged to 1911 cc for the 319/1. This was a result of increasing the bore to 65 mm (2.6 in) and the stroke to 96 mm (3.8 in). This engine produced 55 bhp (41 kW) at 4000 rpm.
Applications:

• 1935-1937 319/1

M78 (326 version)

The 319 engine was enlarged to 1971 cc for the 326 by increasing the bore by one millimetre to 66 mm (2.6 in). Twin 26 mm Solex carburetors were used. The compression ratio was raised to 6.0:1. This engine produced 50 PS (37 kW) at 3750 rpm.
Applications:

• 1936-1946 326
• 1938-1950 321

M78 (320 version)

The 326 engine was detuned (by using a single carburetor) for the 320 and 321. This engine produces 34 kW (46 PS; 46 hp) at 3750 rpm.
Applications:

• 1937-1938 320
• 1938-1941 321

M78 (327 version)

The 327 used a version of the 326 engine with a new cylinder head, yielding a 6.3:1 compression ratio and a slight power increase to 55 bhp (41 kW; 56 PS) at 4500 rpm.
Applications:

• 1937-1955 327
• 1949-1953 340

M337

Main article: BMW M337
The post-war BMW 501 was powered by an updated version of the M78. Redesignated the M337, the updated engine had a revised cylinder head, a completely new inlet manifold, and a reinforced crankshaft with bigger, more modern bearings.

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Last updated on 10 March 2013 at 09:59.

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The BMW M337 is a straight-6 OHV piston engine which replaced the BMW M78 and was produced from 1952-1958.
Built to power BMW's first new car after the Second World War, the M337 engine was a significant update of the M78. The cylinder head was revised, the inlet manifold was a new design, and a reinforced crankshaft with bigger, more modern bearings was used.

Manufacturer	BMW
Production	1952 - 1958
Predecessor	BMW M78
Successor	BMW OHV V8 engine
Configuration	straight-6

Models

Model	Displacement	Power	Torque	Year
337/1	1,971 cc	48 kW (65 PS; 64 hp)	129 Nm (95 lbft)	1952-1954
337/2	1,971 cc	54 kW (73 PS; 72 hp)	130 Nm (96 lbft)	1954-1955
337/3	2,077 cc	54 kW (73 PS; 72 hp)	135 Nm (100 lbft)	1955-1958

M337/1

The first version of the M337 engine has a displacement of 1971 cc. It produces 48 kW (65 PS; 64 hp) at 4400 rpm and 129 N·m (95 lb·ft) at 2000 rpm.
Applications:

• 1952-1954 501

M337/2

In 1954, a revised engine producing 54 kW (73 PS; 72 hp) at 4400 rpm and 130 N·m (96 lb·ft) at 2500 rpm was released. The compression ratio for this engine is 6.8:1.
Applications:

• 1954-1955 501A
• 1954-1955 501B

M337/3

This version was bored out by 2 mm (0.1 in) , which increased displacement to 2077 cc. Despite the increase in displacement and an increased in compression ratio of 7.0:1, the engine produced no more power than the previous version. However torque increased 135 Nm (100 lbft) at 2500 rpm.
Applications:

• 1955-1958 501/3

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Last updated on 15 August 2012 at 00:09.

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The BMW M328 is a straight-6 OHV piston engine which was produced alongside the M78 from 1936 to 1940. It was a high-performance development of the M78 engine, and was made for use in the BMW 328 sports car. An aluminium cylinder head with a hemispherical cross-flow combustion chamber was developed for this engine.
The M328 had an unusual valvetrain design. While the camshaft was located in the block (as per OHV engines), the exhaust valves were controlled by a transverse pushrod from the intake valves. This meant the valve layout is similar to a DOHC engine. With a bore of 66 mm (2.6 in) and a stroke of 96 mm (3.8 in), the displacement was 1971 cc, the same as M78 engine used in the BMW 326. Three Solex "30 JF downdraft" carburetors were used on the M328.

Models

Model	Displacement	Power	Torque	Year
M328	1,971 cc	51 kW (69 PS; 68 hp)		1936-1940

M328

The M328 engine has a compression ratio of 7.5:1 and produces 80 PS (59 kW) at 5000 rpm.
Applications:

• 1936-1940 328
• 1937-1940 327/28

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Last uodated on 20 August 2012 at 10:12.

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The BMW M88 is a straight-6 DOHC piston engine produced from 1978 to 1989. It is based on the M49 engine motorsport, que was used in the BMW 3.0CSi.

Design

BMW engineers used a 4-valve head and a single-row timing chain. Kugelfischer fuel injection was used with single throttle valves and the distinctive six inlet pipes.

Models

Engine	Disp	Power	Torque	Bore	Stroke	Year	Application
M88/1	3,453 cc (211 cu in)	203 kW (272 hp) @ 6500 rpm	330 Nm (243 lbft) @ 5000 rpm	93.4 mm (3.7 in)	84 mm (3.3 in)	1978–1981	BMW M1
M88/2		670 kW (898 hp)					Group 5 racing cars
M88/3		210 kW (282 hp) @ 6500 rpm	340 Nm (251 lbft) @ 4500 rpm			1983–1989	BMW E28 M5, BMW M635CSi
M90		160 kW (215 hp) at 5,200 rpm	304 Nm (224 lbft) at 4,000 rpm			1978–1982	E24 635CSi, E12 M535i, E23 735i

M88/1

The M88/1 was the first iteration of the M88 and was fitted to the BMW M1  Between It produced 277 hp (207 kW) @ 6500rpm and 239 lbft (324 Nm) @ 5500rpm.

M88/2

For Group 5 racing, the M88 engine was turbocharged and Became Known as the M88 / 2. This race engine produced up to 900 hp (670 kW).

M88/3

The M88/1 engine was modified for use in the M635CSi and E28 M5, This engine was Known as the M88/3. The Kugelfisher fuel injection was Replaced with Bosch Motronic and the engine produced 286 hp (213 kW). It has a compression ratio of 10.5:1.
The M88/3 was Also fitted to the South African 745i, due to packaging problems with the turbocharged engine M102 Which was used in other markets.

M90

The M90 engine is a SOHC Engine That lower performance was based on the M88/1. It uses TO the same block from the M88 and Maintains the same bore and stroke, but uses Both Bosch Motronic fuel injection and Bosch L-Jetronic. Typically Identified by a white L painted on the block behind the oil filter housing.

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Last updated on 14 May 2013 at 11:02.

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BMW M12/M13 engine

The BMW M12/13 turbo 1500 cc 4-cylinder turbocharged Formula One engine, based on the standard BMW M10 engine introduced in 1961, powered the F1 cars of Brabham, Arrows and Benetton and won the world championship in 1983.
As BMW M12, the engine design since the 1960s became one of the most successful engines in racing. Starting with the European Touring Car Championship, it was also used in Formula 2, expanded to two litre and fitted with four-valve heads, producing over 300 hp (224 kW). In the Deutsche Rennsport Meisterschaft, a 1400 cc variant (with a 1.4 handicap factor equal to 2000cc) was turbocharged by Paul Rosche according to FIA Group 5rules. At well over 350 hp (261 kW) from the beginning, it rendered the normally aspirated engines in the two liter category useless. After some development, power, driveability and reliability improved, especially in the IMSA car, and BMW began to think about entering F1, where a handicap factor of 2.0 required 1500 cc engines.

With the BMW badged as Megatron in this A10B chassis, drivers Eddie Cheever (pictured at the 2008 Goodwood Festival of Speed) and Derek Warwick ensured that 1988 was Arrows' most successful year in Formula One, thanks to frequent points finishes

In 1983, Brazilian driver Nelson Piquet won the Formula One World Championship driving a Brabham BT52 powered by the turbocharged BMW M12 engine, which in 1983 was producing approximately 850 bhp (630 kW) in qualifying trim and 640 bhp (480 kW) for the races. Piquet, who won theBrazilian, Italian and European Grands Prix in 1983, won the championship by just two points in front of Renaults Alain Prost (Renault had pioneered turbocharging in F1 in 1977). Piquet's win was the first time a car powered by a turbocharged engine had won the World Championship.
In the years 1986 and 1987, the version M12/13/1 was tilted sideways by 72° for use in the extremely low Brabham BT55 (1986) and more conventional Brabham BT56 (1987). The design was not successful, probably due to cooling issues in the tight compartment. The 1986 engine was said to produce about 1,400 hp (1,044 kW) in qualifying, that being the most powerful figure of all the turbo-charged engines in Formula One (though it should also be noted that at the time there was no way of accurately measuring horsepower over 1,000 and figures are what were generally accepted from the engineers calculations with 0.1 Bar of turbo boost rated to be worth approximately 20 hp (15 kW)).^[1] During 1986 however it was the Benetton team using the conventional upright BMW M12 who would be the leading BMW runner in Formula One, with Gerhard Berger scoring his and the teams first (and the BMW engines last) win by winning the 1986 Mexican Grand Prix. Benetton would not continue with the BMW engines in 1987, instead they became the defacto factory Ford team using their Ford TEC turbo in the BMW's place.
As BMW announced to pull out officially at the end of 1986 (though they would continue to supply Brabham with their tilted engine for 1987), Arrows team boss Jackie Oliver brokered a deal with support from the teams primary sponsor USF&G to continue the use of the upright BMW engines under the name of its subsidiary Megatron, Inc., founded by long-time F1 aficionado John J. Schmidt, who coined the phrase "Horse racing may have been the sport of kings, but auto racing is the sport of corporations". The engines were serviced by Arrows long time engine guruHeini Mader from Switzerland, a former mechanic of Jo Siffert.
Rebadged as Megatron, the BMW engines were used by the Arrows team for the1987 and 1988 seasons, as well as Ligier for 1987 only. In the final season for the turbos, Arrows were one of only six teams still running turbocharged engines and the only team to still use the old BMW engines. During the 1988 season the Megatron engines were the oldest turbos still in use in Formula One dating back to 1982 (Ferrari, who had been using turbos since 1981, had introduced a completely new engine from 1987).
The Megatron programme ended as a result of a change of Formula One engine rules which banned turbocharged engines at the end of 1988, with American driver Eddie Cheever achieving the old BMW engines last podium finish with third place in the 1988 Italian Grand Prix at Monza. The race was also significant as it was the first time Heini Mader had solved the problem caused by theFIA's pop-off valve which limited turbo power to 4.0 Bar in 1987 and 2.5 Bar in 1988. By moving the valve closer to the engine, the problem of the turbo not delivering enough boost had been solved and the Arrows A10B's were among the fastest on the long Monza straights, faster even than the all-conquering McLaren-Hondas which effectively incorporated Gordon Murray's lowline Brabham design as well as featuring a more powerful V6 engine.
With turbos banned from the 1989 season, the Arrows team reverted to using 3,499 cc (213.5 cu in), naturally aspirated Ford DFR V8 power plants.
The Formula 2 M12 was also the basis for the highly successful BMW M3 Group A touring car. The 2.3 liter engine powered the M3 (which really was a middle class car compared to its rivals such as the Ford Sierra RS500) to the 1987 World Touring Car Championship, the 1987 and 1988 European Touring Car Championship's, the 1987 Australian Touring Car Championship, the 1988 British Touring Car Championship, and the 1987 and 1989-93 Italian Touring Car Championships.

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Last updated on 17 August 2013 at 17:56.

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