Engineering:BMW M51

From HandWiki
BMW M51
M51 Motor.JPG
Overview
ManufacturerBMW
Production1991-2000
Layout
ConfigurationInline-6
Displacement2.5 L; 152.4 cu in (2,497 cc)
Cylinder bore80 mm (3.15 in)
Piston stroke82.8 mm (3.26 in)
Block materialCast iron
ValvetrainSOHC 2 valves x cyl.
Compression ratio22.0:1
Combustion
TurbochargerSingle turbo, tds-engines also have an intercooler
Fuel systemSwirl-chamber-injection
ManagementBosch DDE 2.1
Fuel typeDiesel fuel (DIN 51601)
Cooling systemWater-cooled
Output
Power output85–105 kW (114–141 hp)
Torque output222–280 N⋅m (164–207 lb⋅ft)
Dimensions
Dry weight132 kg (291 lb)
Chronology
PredecessorBMW M21
SuccessorBMW M57

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.

Description

The M51 is a water-cooled and turbocharged inline six-cylinder diesel engine with a Bosch VP37-swirl-chamber-injection.[1][2][3] The displacement is 2.5 L; 152.4 cu in (2,497 cc) and the compression ratio is 22.0:1.

Some engine variants have an intercooler in addition to the turbocharger, they can be identified by the tds.[2] The M51 is an engine made of cast iron, it has one chain driven overhead camshaft[4] and two valves per cylinder.[2][4] Compared to the M21 the M51 now has tappets and a hydraulic valve lash adjustment.[2] The fuel injection in the first engines and all E36 models is controlled by the ECU Bosch DDE 2.1, which was replaced after the first technical revision by the DDE 2.2[4] This results 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[lower-alpha 1] 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[lower-alpha 2] 100 kW (136 hp)
at 4400 rpm[12]
270 N⋅m (199 lb⋅ft)
at 2300 rpm
1995-2001
  1. For Opel Omega B only
  2. For Range Rover P38 DSE 2.5 LP2 only.

Applications:

  • 1991 - 1996 E36 325td (M51D25 UL)
  • 1996 - 1998 E36 325td (M51D25TÜ UL)
  • 1993 - 1996 E36 325tds (M51D25 OL)
  • 1996 - 1998 E36 325tds (M51D25TÜ OL)
  • 1992 - 1996 E34 525td (M51D25 UL)
  • 1991 - 1996 E34 525tds (M51D25 OL)
  • 1996 - 2000 E39 525tds (M51D25TÜ OL)
  • 1996 - 2000 E39 525td (M51D25TÜ UL)
  • 1996 - 2000 E38 725tds (M51D25TÜ OL)
  • 1995 - 2001 Land Rover Range Rover 2.5 D/DSE
  • 1995 - 2001 Opel Omega
  • 1992 UMM Alter II (single example; engine, gearbox, and electronics were fitted by BMW in Munich)

See also

References