BMW M51
Reciprocating internal combustion engine
From Wikipedia, the free encyclopedia
The BMW M51 is an inline-6 cylinder Diesel engine produced by the Upper Austrian BMW plant in Steyr from July 1991 through February 2000. Its predecessor is the BMW M21; the successor is the BMW M57.
| BMW M51 | |
|---|---|
| |
| Overview | |
| Manufacturer | BMW |
| Production | 1991-2000 |
| Layout | |
| Configuration | Inline-6 |
| Displacement | 2.5 L; 152.4 cu in (2,497 cc) |
| Cylinder bore | 80 mm (3.15 in) |
| Piston stroke | 82.8 mm (3.26 in) |
| Cylinder block material | Cast iron |
| Valvetrain | SOHC 2 valves x cyl. |
| Compression ratio | 22.0:1 |
| Combustion | |
| Turbocharger | Single turbo, tds-engines also have an intercooler |
| Fuel system | Swirl-chamber-injection |
| Management | Bosch DDE 2.1 |
| Fuel type | Diesel fuel (DIN 51601) |
| Cooling system | Water-cooled |
| Output | |
| Power output | 85–105 kW (114–141 hp) |
| Torque output | 222–280 N⋅m (164–207 lb⋅ft) |
| Dimensions | |
| Dry weight | 132 kg (291 lb) |
| Chronology | |
| Predecessor | BMW M21 |
| Successor | BMW M57 |
Description
The M51 is a water-cooled and turbocharged inline six-cylinder diesel engine. It is an indirect injection design with fuel supplied by a Bosch VP37 mechanical injection pump.[1][2][3] The displacement is 2,497 cc (152.4 cu in) and the compression ratio is 22.0:1.
Some engine variants have an intercooler in addition to the turbocharger; vehicles so equipped can be identified by the designation tds.[2] The M51 has a cast iron block and aluminum head, one chain driven overhead camshaft,[4] and two valves per cylinder.[2][4] Compared to the M21 the M51 features tappets and hydraulic valve lash adjustment.[2] The fuel injection in the first engines and all E36 models is controlled by the Bosch DDE 2.1, which was replaced after the first technical revision by DDE 2.2,[4] resulting in greater torque at lower revs.[4] For lubrication SAE 5W-40 oil is used.[5]
| Version | Power | Torque | Years |
|---|---|---|---|
| M51D25 UL | 85 kW (115 hp) at 4800 rpm | 222 N⋅m (164 lb⋅ft) at 1900 rpm | 1991–1997 |
| M51D25 OL | 105 kW (143 hp) at 4800 rpm | 260 N⋅m (192 lb⋅ft) at 2200 rpm | 1991–1996 |
| Opel X25DT[a] | 96 kW (130 hp) at 4800 rpm[6][7][8][9] | 250 N⋅m (184 lb⋅ft) at 1400 rpm | 1994–2001 |
| M51D25TÜ UL | 85 kW (115 hp) at 4800 rpm[10][11] | 230 N⋅m (170 lb⋅ft) at 1900 rpm | 1996–1998 |
| M51D25TÜ OL | 105 kW (143 hp) at 4800 rpm[4] | 280 N⋅m (207 lb⋅ft) at 2200 rpm | 1996–1998 |
| M51D25TÜ OL | 105 kW (143 hp) at 4600 rpm[4] | 1998–2000 | |
| M51D25M1[b] | 100 kW (136 hp) at 4400 rpm[12] | 270 N⋅m (199 lb⋅ft) at 2300 rpm | 1995-2001 |
- For Opel Omega B only
- For Range Rover P38 DSE 2.5 LP2 only.
Applications:
- 1991 - 1996 BMW 325td (M51D25 UL)
- 1996 - 1998 BMW 325td (M51D25TÜ UL)
- 1993 - 1996 BMW 325tds (M51D25 OL)
- 1996 - 1998 BMW 325tds (M51D25TÜ OL)
- 1992 - 1996 BMW 525td (M51D25 UL)
- 1991 - 1996 BMW 525tds (M51D25 OL)
- 1996 - 2000 BMW 525tds (M51D25TÜ OL)
- 1996 - 2000 BMW 525td (M51D25TÜ UL)
- 1996 - 2000 BMW 725tds (M51D25TÜ OL)
- 1995 - 2001 Range Rover (P38A)
- 1995 - 2001 Opel Omega B
- 1992 UMM Alter II (single example; engine, gearbox, and electronics were fitted by BMW in Munich)