17/06/2015
The Heart of Executive Luxury: Understanding the BMW 740i Engine
The BMW 7 Series has long been synonymous with executive luxury and sophisticated driving. For many enthusiasts, the "740i" designation represents a sweet spot in the model's history, offering a potent blend of performance and refinement. But what kind of engine powers this esteemed saloon? The answer, as with many things in the automotive world, is not entirely straightforward and has evolved significantly over the generations. This article delves into the mechanical heart of the BMW 740i, exploring its various iterations and the engineering prowess that has defined its legacy.
A Legacy of Sixes and Eights: The Evolution of the 740i
BMW's journey into the executive saloon segment was a gradual one, with the E23 generation marking its initial serious foray. However, it was with subsequent generations that the "740i" moniker truly began to carve out its identity. To understand the engine behind a 740i, we need to look at the specific chassis codes that define its era:
The E32 Generation (1986-1994): A New V8 Era Begins
The E32 generation of the 7 Series was a significant step forward for BMW, introducing a more modern and elegant design, along with a crucial expansion of its engine offerings. For the 740i variant in this generation (specifically the later models, as the 730i and 735i were more common initially), BMW introduced its first mainstream V8 engine. This was a landmark moment, as it moved away from the inline-six engines that had dominated previous generations and positioned the 7 Series more directly against its primary rivals.
The engine in question was the M60. This was a 4.0-litre (3982cc) V8 powerhouse, designed with advanced features for its time. It featured an aluminium block and cylinder heads, contributing to a lighter overall weight and improved handling. The V8 configuration provided a smoother, more refined power delivery compared to an inline-six, which is highly desirable in an executive saloon.
Key characteristics of the E32 740i's M60 V8:
| Specification | Details |
|---|---|
| Engine Code | M60B40 |
| Configuration | 4.0L V8 |
| Power Output (approx.) | 282 bhp (210 kW) |
| Torque (approx.) | 295 lb-ft (400 Nm) |
| Fuel System | Bosch Motronic |
| Valvetrain | 4 valves per cylinder, DOHC |
The M60 engine was a testament to BMW's engineering skill, offering a compelling blend of performance and a sophisticated exhaust note. It helped solidify the 7 Series' reputation as a serious contender in the luxury car market.
The E38 Generation (1994-2001): Refinement and More Power
The E38 generation saw further evolution of the 7 Series, and with it, an updated 740i. While the E32 had introduced the V8, the E38 refined the concept. The primary engine for the 740i in this era was the M62. This was an evolution of the M60, featuring a larger displacement of 4.4 litres (4398cc).
The M62 V8 brought with it improved performance and, in some iterations, features like Double VANOS (variable camshaft timing on both intake and exhaust camshafts), enhancing both power delivery and fuel efficiency. The E38 740i offered a more potent and smoother driving experience than its predecessor, further cementing its status as a benchmark for executive motoring.
Key characteristics of the E38 740i's M62 V8:
| Specification | Details |
|---|---|
| Engine Code | M62B44 |
| Configuration | 4.4L V8 |
| Power Output (approx.) | 282 bhp (210 kW) for early models, later increased to 290 bhp (216 kW) |
| Torque (approx.) | 310 lb-ft (420 Nm) for early models, later increased to 325 lb-ft (440 Nm) |
| Fuel System | Bosch Motronic |
| Valvetrain | 4 valves per cylinder, DOHC (with Double VANOS on later models) |
The E38 740i is often considered a high point for the 7 Series, praised for its blend of technological innovation, understated luxury, and a truly magnificent V8 engine. The M62TU (Technical Update) version, in particular, offered a noticeable bump in performance.
The F01/F02 Generation (2008-2015): A Return to the Inline-Six for the 740i
Fast forward to the F01/F02 generation, and the landscape of the 740i changed once again. BMW, in its pursuit of efficiency and emissions reduction, reintroduced the inline-six engine for the 740i designation. However, this was no ordinary inline-six. It was a 3.0-litre (2996cc) TwinPower Turbo (or Twin-Scroll Turbo) inline-six engine, carrying the engine code N54B30 for earlier models and later the N55B30.
This move demonstrated BMW's advanced turbocharging technology, proving that a smaller, turbocharged inline-six could deliver comparable, and in some metrics, even superior performance to the larger V8s of previous generations. The 740i in this era offered a more responsive and agile driving experience, with excellent torque available from lower revs.
Key characteristics of the F01/F02 740i's Turbocharged Inline-Six:
| Specification | Details |
|---|---|
| Engine Code | N54B30 / N55B30 |
| Configuration | 3.0L Inline-6 (Turbocharged) |
| Power Output (approx.) | 315-320 bhp (235-239 kW) |
| Torque (approx.) | 330 lb-ft (450 Nm) |
| Fuel System | Direct Injection |
| Valvetrain | 24 valves, DOHC (with Double VANOS and Valvetronic on N55) |
This generation highlighted BMW's commitment to turbocharging technology, offering a potent and efficient package that redefined expectations for a 740i.
The G11/G12 Generation (2015-2022): Further Evolution and Hybridisation
The G11/G12 generation continued the trend of turbocharged engines. The 740i in this era featured a 3.0-litre (2998cc) B58 inline-six engine, again employing BMW's TwinPower Turbo technology. This engine represented a significant leap in efficiency, refinement, and power delivery, building upon the successes of the N55.
Furthermore, this generation introduced the concept of hybridisation to the 740i badge with the 740e (later 745e). This model combined the B58 inline-six with an electric motor and battery pack, offering enhanced performance and the ability to drive on electric power alone for short distances. The 745e, for instance, boasted a combined output of around 394 bhp.
Key characteristics of the G11/G12 740i's B58 Turbocharged Inline-Six:
| Specification | Details |
|---|---|
| Engine Code | B58B30 |
| Configuration | 3.0L Inline-6 (Turbocharged) |
| Power Output (approx.) | 322 bhp (240 kW) |
| Torque (approx.) | 330 lb-ft (450 Nm) |
| Fuel System | Direct Injection |
| Valvetrain | 24 valves, DOHC (with Double VANOS and Valvetronic) |
The G11/G12 740i showcases BMW's commitment to powertrain innovation, balancing performance, luxury, and increasing demands for efficiency and reduced emissions.
What Engine Does a 740i Have? A Summary
To directly answer the question "What kind of engine does a 740i have?", it's crucial to specify the generation:
- E32 740i: Typically a 4.0-litre V8 (M60B40).
- E38 740i: Typically a 4.4-litre V8 (M62B44), with later models featuring Double VANOS.
- F01/F02 740i: A 3.0-litre turbocharged inline-six (N54B30 or N55B30).
- G11/G12 740i: A 3.0-litre turbocharged inline-six (B58B30). The 740e/745e variant is a plug-in hybrid version using a similar inline-six.
Performance and Driving Experience
Regardless of the specific engine, the BMW 740i has consistently been engineered to provide a refined and engaging driving experience. The V8 models offered effortless torque and a smooth, powerful surge, ideal for long-distance cruising and confident overtaking. The turbocharged inline-six models, while smaller in displacement, provided impressive responsiveness, a wider torque band, and often better fuel economy, demonstrating BMW's mastery of forced induction.
The characteristic BMW driving dynamics, often described as "The Ultimate Driving Machine," are present in all 740i variants. While the focus is on executive comfort, the engineering ensures that the driver remains connected to the road, with precise steering and well-balanced chassis.
Maintenance Considerations
Owning a BMW 740i, especially older models, requires diligent maintenance to ensure longevity and optimal performance. Key areas to focus on include:
- Oil Changes: Regular oil and filter changes are paramount, especially for the V8 engines, using high-quality synthetic oil recommended by BMW.
- Cooling System: The cooling system, including the radiator, water pump, and hoses, needs regular inspection as overheating can cause significant damage.
- Timing Chain: While generally robust, the timing chains and guides on the M62 and subsequent engines are critical. Listen for any rattling noises on startup, which can indicate wear.
- Ignition System: Spark plugs and ignition coils should be replaced at recommended intervals.
- Fluid Flushes: Regular flushing of brake fluid, power steering fluid, and transmission fluid (if applicable) is essential.
Frequently Asked Questions
Q1: What is the most common engine in a BMW 740i?
A1: The most common engines depend on the generation. For the E32 and E38 generations, it was a V8. For the F01/F02 and G11/G12 generations, it's a turbocharged inline-six.
Q2: Are the engines in the 740i reliable?
A2: BMW engines are generally well-engineered. However, like any complex machine, they require regular and proper maintenance. Older V8 engines, while powerful, can be more costly to maintain if issues arise. Turbocharged inline-sixes are often praised for their blend of performance and reliability when maintained correctly.
Q3: What is the difference between an E38 740i and an F01 740i engine?
A3: The E38 740i uses a 4.4-litre naturally aspirated V8 (M62), while the F01 740i uses a 3.0-litre turbocharged inline-six (N54/N55). The latter offers more modern technology, better fuel efficiency, and often a more responsive feel due to the turbocharger.
Q4: Does the 740i have a V8 engine in newer models?
A4: In recent generations (G11/G12 and onwards), the 740i designation has primarily been associated with a 3.0-litre turbocharged inline-six engine. Higher-tier models, like the 750i or M760Li, typically feature V8 or V12 engines, respectively.
Conclusion
The BMW 740i has worn different engine configurations throughout its illustrious history, each iteration reflecting BMW's commitment to advancing automotive technology. From the smooth, potent V8s of the E32 and E38 generations to the efficient and powerful turbocharged inline-sixes of later models, the 740i has consistently delivered a compelling blend of luxury and performance. Understanding the specific engine for each generation is key to appreciating its engineering and ensuring its continued enjoyment for years to come. The legacy of the 740i is one of continuous improvement and a steadfast dedication to the executive driving experience.
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