BMW M70

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BMW
BMW M70 in a BMW E31

BMW M70 in a BMW E31
M70
Production period: 1987-1994
Manufacturer: BMW
Working principle: Otto
Motor design: 60 ° V engine
Valve control: OHC
Displacement: 4988 cm 3
Mixture preparation: Manifold injection
Engine charging: no
Power: 220 kW
Torque: 450 Nm
Dimensions: 240 kg
Previous model: none
Successor: BMW M73

The BMW M70 is a V12 gasoline engine from the car manufacturer BMW and was introduced in 1987. It was used in the 750i / 750iL BMW E32 and the 850i / Ci BMW E31 . The four-cylinder Formula 3 racing engine M70 based on the BMW M10 must be considered separately from this .

Conception

The M70 should be a 200 kW quietest border engine with five liters, which for unleaded 91-octane - petrol is suitable. BMW decided to develop a short-stroke 60 ° V12 engine, as smaller cylinders allow greater compression, the larger number of cylinders means that the ignition intervals are shorter and the torque curve is therefore more even. Because of the V12 design of the engine and the resulting almost complete balance of masses , the M70 should run smoothly. The specific achievement should result from high specific work.

technology

The BMW M70 is a 220 kW 12-cylinder V-engine with a crankcase made of an aluminum - silicon alloy. The silicon should minimize wear. The bore is 84 mm, the piston stroke 75 mm, so that there is a total displacement of 4988 cm 3 . Bore and stroke match those of the M20B25 . The pistons are made of an aluminum alloy and coated with iron, the piston bowls are aligned with the spark plug . The crankshaft , with seven bearings and forged from C45E tempered steel, is mounted in three-material bearing shells like the BMW M21 . There are always two connecting rods hinged to the same crank pin. The crankshaft has twelve counterweights.

Each cylinder has two valves, the valve head of the inlet valve (diameter of 42 mm) is 44% larger than that of the exhaust valve (diameter of 35 mm). The valves are operated by rocker arms from an overhead camshaft with seven bearings , which is driven by a chain. The engine has one camshaft ( SOHC ) per cylinder bank ; Because of the connecting rod linkage and cylinder position, the camshafts of the left and right cylinder banks are of different lengths. Two digital engine electronics (DME) of the type Bosch Motronic 1.2 (early E32 ) and 1.7 ( E31 , late E31) individually regulate the partially sequential intake manifold injection and the ignition timing for each cylinder bank . The two DMEs are monitored by the electronic engine power control EML. The two throttle valves of the engine are synchronized with the EML control unit, which opens or closes the throttle valve according to the position of the accelerator pedal. The EML control unit also monitors the electronic driving aids. The ancillaries of the M70 are belt driven.

In principle, the M70 consists of two M20B25 six-cylinder engines, which share little more than the crankshaft and the return of the fuel to the tank, almost all other components are present in duplicate: fuel pump with feed, fuel pressure control, injection system with control units and exhaust system with one each separate line, each with a catalytic converter and independent lambda control. The redundancy goes so far that even one bank of the engine can go into limp-home mode independently of the other.

Offshoot

The S70 was developed on the basis of the M70, the variants of which have a larger displacement and significantly higher performance. Alpina built its own engine based on the M70, the D1 / 1 and based on the S70 the D2, which was used in the B12 Coupé, among other things.

Technical specifications

Technical data M70

M70
Engine type 60 ° V12 light alloy engine
cooling Water cooling
Valve control OHC valve control , valves hanging at a 14 ° V angle, two per cylinder, operated
by an overhead camshaft via rocker arms
Engine control unit Bosch Motronic 1.2
Mixture preparation Manifold injection
Bore × stroke 84 mm × 75 mm
Displacement 4988 cm 3
Firing order 1-7-5-11-3-9-6-12-2-8-4-10
rated capacity 220 kW at 5200 min -1
maximum torque 450 N · m at 4100 min -1
Specific performance 44.1 kW / dm 3
Medium piston speed 13 m / s
Maximum speed 6000 ± 40 min −1
Highest continuous speed 5900 min −1
Idle speed 700 ± 50 min −1
compression 10-12 bar
Compression ratio 8.8: 1
fuel Unleaded 91 RON petrol
Dimensions 240 kg
Fill quantity of the oil circuit 7.5 l

Technical data for branch motors

engine Displacement Valves / cyl. Bore × stroke compression Power at 1 / min Torque at 1 / min construction time
S70B56 5576 cm 3 2 86 mm × 80 mm 9.8: 1 280 kW (380 hp) at 5300 550 Nm at 4000 1992-1996
S70 / 2 6064 cm 3 4th 86 mm × 87 mm 11.0: 1 461 kW (627 hp) at 7500 651 Nm at 5600 1994-1998
S70 / 3 5990 cm 3 4th 86 mm × 85.9 mm 467 kW (635 hp) at 8000 670 Nm at 5000 1997-1999
D1 / 1 4988 cm 3 2 84 mm × 75 mm 9.5: 1 257 kW (350 hp) at 5300 470 Nm at 4000 1990-1994
D2 5646 cm 3 2 86 mm × 81 mm 10.5: 1 306 kW (416 hp) at 5400 570 Nm at 4000 1992-1996

use

M70

  • 1987–1994 in the BMW E32 750i / 750iL
  • 1989–1992 in the BMW E31 850i
  • 1993–1994 in the BMW E31 850Ci

S70

S70 / 2

S70 / 3

D1 / 1

D2

source

Web links

Commons : M70 engine  - collection of pictures, videos and audio files

Individual evidence

  1. ^ BMW M70 and S70 Engines (1987-96) , in Australian Car Reviews
Timeline of BMW gasoline engines for passenger cars since 1961
Number of cylinders Conception 1960s 1970s 1980s 1990s 2000s 2010s
0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th
3 1.5 l B38
4th (1.5–2.0 l) M10
M40
M42
M43
M44
N40
N42
N45
N46
N43
N13
N20
B48
High performance motor S14
6th Small six-cylinder (2.0-3.0 l) M20
M50
M52
M54
Large six-cylinder (2.5-3.5 l) M30
N52
N53
N54
N55
B58
High performance motor M88
S38
S50
S52
S54
S55
8th 3.0-4.4 l M60
M62
N62
N63
High performance motor S62
S63
S65
10 High performance motor S85
12 5.0-6.6 l M70
M73
N73
N74
High performance motor S70
Number of cylinders Conception 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th
1960s 1970s 1980s 1990s 2000s 2010s