The BMW M54B25 engine features a cast aluminum alloy cylinder block with cast iron cylinder liners. The aluminum cylinder head uses double chain-actuated overhead camshafts (DOHC) and four valves per cylinder (24 valves total). It is equipped with a Siemens MS 43 engine management system, double VANOS (BMW Variable Valve Timing System) for the intake and exhaust camshafts, fully electronic throttle without mechanical backrest, double-length intake manifold (called “DISA” by BMW), a distributorless ignition system with individual ignition coils for each cylinder and an electronically controlled thermostat.
It has a cylinder bore of 84.0 mm (3.31 in.) And a piston stroke of 75.0 mm (2.95 in.). Compression ratio ratio is 10.5: 1. The M54B25 engine produced 192 PS (141 kW; 189 HP) at 6,000 rpm peak power and 245 Nm (25 kgm, 180.6 ftlb). at 3,500 rpm of maximum torque.
The engine code breakdown is as follows:
- M54 – Engine family
- B – gasoline
- 25 – 2.5 liter displacement
|Design||Four-stroke, Inline-6 (Straight-6)|
|Displacement||2.5 L, 2,494 cc (152.2 cu in)|
|Fuel system||Fuel injection system|
|Max. horsepower||192 hp (141 kW; 189 hp) at 6,000 rpm|
|Max. torque||245 Nm (25 kgm, 180.6 ftlb) at 3500 rpm|
|Order to open fire||1-5-3-6-2-4|
|Dimensions (L x H x W):||–|
|Weight||130 kg (286.6 pounds)|
The M54B25 engine uses a cast aluminum alloy cylinder block with cast iron cylinder liners, the bore is 84.0 mm (3.31 in) and the piston stroke is 75.0 mm (2.95 in). The compression ratio is 10.5: 1. The cylinders are exposed to circulating coolant on all sides. Counterbalanced cast iron crankshaft rotates in replaceable split casing main bearings. This motor uses seven main bearings.
Forged steel connecting rods use replaceable split casing bearings at the end of the crankshaft and solid bushings at the end of the piston pin. The pistons are of the three-ring type with two upper compression rings and a one-piece lower oil scraper ring. The fully floating piston pins are retained with snap rings.
|Cylinder Block Alloy||Aluminium alloy|
|Compression ratio:||10.5: 1|
|Cylinder bore:||84.0 mm (3.31 inches)|
|Piston stroke:||75.0 mm (2.95 inches)|
|Number of piston rings (compression / oil):||2/1|
|Number of main bearings:||7|
|Cylinder bore (standard):||84.000-84.010 mm (3.3071-3.3075 inches)|
|Piston Skirt Diameter (Standard):||83.995 mm (3.3069 inches)|
|Piston Pin Outside Diameter:||22,000 mm (0.8661 in.)|
|Piston ring side clearance:||Top||0.020-0.060 mm (0.0008-0.0024 inch)|
|Second||0.020-0.060 mm (0.0008-0.0024 inch)|
|Petroleum||0.015-0.060 mm (0.0006-0.0024 inch)|
|Piston Ring End Gap:||Top||0.200-0.400 mm (0.0079-0.0157 inch)|
|Second||0.200-0.400 mm (0.0079-0.0157 inch)|
|Petroleum||0.200-0.450 mm (0.0079-0.0177 inch)|
|Crankshaft journal diameter:||60,000 mm (2.3622 in.)|
|Crankpin diameter:||45,000 mm (1.7717 inches)|
The cylinder head is made of an aluminum alloy with good cooling efficiency. The M54B25 engine uses chain-actuated dual overhead camshafts and four valves per cylinder. The standard head height is 140.0 mm (5.5118 in). The cylinder head employs a cross flow design for increased power and efficiency. Intake air enters the combustion chamber from one side while exhaust gases exit from the other. This engine is equipped with a dual VANOS (variable camshaft timing) system. VANOS is fully variable and works independently on both the intake and exhaust sides.
The intake valves are 33.0 mm (1.2992 in) diameter and the exhaust valves are 30.5 mm (1.2008 in). Lasting 228 ° for inlet and 244 ° for exhaust valves, valve lift is 9.0 mm (0.3543 in) for …