The BMW N46 was an inline four-cylinder petrol engine that was available from 2004 to 2012. The N46 replaced BMW’s N42 engine, though changes were relatively minor.
The N46 engine had an aluminium alloy block and cylinder head, two gear-driven balance shafts, double overhead camshafts (chain-driven), variable intake and exhaust valve timing (BMW’s double VANOS), four valves per cylinder, variable intake valve lift (BMW’s Valvetronic) and Bosch MEV 9.2 engine management.
The N46B20 engine was also fitted with a variable intake manifold (BMW’s Differentiated Intake System, or DISA) which enabled intake pipe length to be adjusted according to engine speed for more efficient cylinder filling and scavenging. The N46B18 engine, however, omitted the DISA system.
Relative to the N42, the N46 engine introduced changes for the balance shafts, connecting rods, ignition, vacuum pump, roller cam and cylinder head cover. The N46 also introduced Bosch MEV 9.2 with an integrated Valvetronic control unit (previously Bosch Motronic ME 9.2). In 2006, however, the updated N46N engine was released and it had Bosch MV17.4.6 engine management.
| Engine | Capacity | Peak power | Peak torque | Models | Years |
|---|---|---|---|---|---|
| N46B18 | 1796 cc (84.0 x 81.0) |
85kW at 5500rpm | 175Nm at 3750rpm | E46 316i, E46 316ti |
2003-05 |
| N46B20 | 1995 cc (84.0 x 90.0) |
95kW at 5750rpm | 180Nm at 3250rpm | E87 118i, E90 318i |
2004-07 |
| 105kW at 6000rpm | 200Nm at 3750rpm | E46 318i, E46 318Ci, E46 318ti |
2004-05 | ||
| 110kW at 6200rpm | 200Nm at 3600rpm | E46 318Ci, E84 X1 2.0i, E87 120i, E90 320i, E91 320i |
2004-08 | ||
| 110kW at 6200rpm | 200Nm at 3750rpm | E83 X3 2.0i | 2005-10 | ||
| 110kW at 6400rpm | 200Nm at 3600rpm | E84 X1 sDrive18i | 2010-12 | ||
| N46NB20 | 1995 cc (84.0 x 90.0) |
105kW at 6000rpm | 190Nm at 4500rpm | E81 118i, E87 118i, E90 318i, E91 318i |
2006-12 |
| 125kW at 6400rpm | 210Nm at 4100rpm | E81 120i, E90 320i, E91 320i E60 520i, E61 520i |
2006-12 |
