BMW N54

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BMW N54 engine
JK N54B30.jpg
ManufacturerBMW, Bayerische Motoren Werke AG
Production2006–
PredecessorBMW M54
ClassStraight-6
ManualsService Manual

The N54 is a twin-turbocharged straight-6 automobile engine from BMW. It was launched in late 2006 as a high-performance option for the BMW 3-Series, first to be released along with the new 3-series E92 Coupé, to be followed closely by other existing 3-series models, then with other BMW series as well. It is BMW's first production turbocharged gasoline engine in 26 years since the 745i in 1980. The engine won the International Engine of the Year award in 2007 and 2008.

Models
Engine Displacement Power Torque Redline Year
N54B30 3.0 L (2979 cc/181 in³) 225 kW (306 hp) @ 5800 400 N·m (295 ft·lbf) @ 1300-5000 7000 rpm 2006
N54B30 3.0 L (2979 cc/181 in³) 243 kW (326 hp) @ 5800[1] 450 N·m (332 ft·lbf) @ 1500-4500 7000 rpm 2008

According to BMW, the N54B30 produces 306 hp (228 kW) and 295 ft·lbf/400 N·m. Third party testing has revealed the engine is significantly underrated, producing 332 hp (248 kW) and 311 ft·lbf/422 N·m in one test. [1] The engine uses two small low-pressure turbochargers to remove turbo lag at low elevations. For this reason, the turbo pressure is only 0.4 bar, as the engineering goal was to offer the same driving feel as with naturally aspirated engines. [2] The new engine debuted at the 2006 Geneva Motor Show. The N54B30 does not use the second generation Valvetronic technology found in the N52. The principal advantage of Valvetronic is the reduction of intake vacuum, which is not an issue in the pressurized intake found in a turbo-charged engine. This engine is easily modified with aftermarket tuning to produce in excess of 400 hp.

Surprisingly the engine block of the N54B30 is similar to the older generation BMW M54B30 engine - all aluminum with cast iron cylinder liners. This is due to the fact that the newer N52 aluminum-magnesium engine block was not deemed as suitable for turbo-charging with the above-mentioned engineering goals. As a result, the N54B30 is physically heavier (195 kg/429 lb) than the very light (161 kg/354 lb) N52 engine. This also explains why the engine block size is identical to the older M54B30 at 2979 cc/181 in³ instead of the 2996 cc/182 in³ of the new N52B30 3.0L engine. However, the advantage of the N54B30 engine is that compared to similar power output 225 kW/390 Nm V8 4.0L N62B40 it weighs 70 kg (154 lb) less than the V8, which is massive at 265 kg/583 lb. Additionally, the N54 has higher low-end torque than the V8. It is likely for these reasons BMW chose to develop bi-turbo inline straight-6 engines for the 3-series instead of using heavier V8 engines. Only the new BMW M3 will have a V8 engine in the BMW 3-series, weighing in at 202 kg/445 lb. and generating 414 hp (309 kW) and 295 ft·lbf/400 N·m.

A version of the N54B30 with higher power and torque but across a narrower peak torque band was introduced in the F01 2009 BMW 740i.[1]

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References

See also