| Manufacturer | BMW AG |
|---|---|
| Production | 2007– |
| Predecessor | BMW N52 |
| Class | Straight 6 |
The BMW N53 is BMW's 14th generation production straight 6 engine, released in 2007 in the facelifted BMW 5 Series (E60/E61) and the BMW 3 Series (E90/E91/E92/E93). It is an improvement on the N52 Naturally Aspirated (NA) engine mainly since it has gasoline direct injection technology and can burn stratified. However, unlike its predecessor, it does not contain BMW's Valvetronic technology due to space limitations in the cylinder head[1].BMW does not plan to put the N53 engine for sale in Australian and North American models due to the high sulphur content of the fuel available in these markets.
The N53 makes use of HPI: High Precision Injection or Direct Injection, which consists of Piëzo-electric injectors directly in the cylinder.
The N53B30-O0 has improved maximum power to 272 bhp (203 kW) as well as maximum torque over the N52B30. The N53B30-O0 can be found in the 330i (E90/E91/E92/E93) and 530i (E60/E61).
The 325i (E90/E91/E92) switched from the N52B25-OL (2.5-litre) to the N53B30-U0 (3.0-litre) in September 2007 (March 2007 for the E93). Despite the increased displacement, the maximum power remained unchanged, and maximum torque has increased just enough to compensate for a longer differential final drive ratio as a result of a shorter useful range (maximum power is given in the N53B30-U0 at only 640 rad/s instead of the 700 rad/s of the older N52B25-OL). The N53B30-U0 can also be found in the present 525i (E60/E61).
The 2.5-litre N53B25-U0 can be found in the present 523i (E60/E61)[2].
U0 subcoded engines seem to be crippled versions of their equivalent displacement O0 versions as they share all internal dimensions and technology.
| Engine Code | Displacement | Subcode | Power | Torque | Redline | Year |
|---|---|---|---|---|---|---|
| N53B25 | 2497 cc (152 in³) | U0 | 140 kW (190 bhp) @ 640 rad/s (6100 RPM) | 240 Nm (177 ft·lbf) @ 365-525 rad/s (3500-5000 RPM) | 680 rad/s (6500 RPM) | 2007 |
| N53B30 | 2996 cc (183 in³) | 160 kW (218 bhp) @ 640 rad/s (6100 RPM) | 270 Nm (200 ft·lbf) @ 250-440 rad/s (2400-4200 RPM) | |||
| O0 | 200 kW (272 bhp) @ 700 rad/s (6700 RPM) | 320 Nm (236 ft·lbf) @ 290-315 rad/s (2750-3000 RPM) | 735 rad/s (7000 RPM) |