Exploring Bmw Models Equipped With The N55 Engine

Picture this: you’re scrolling through classifieds, dreaming of a powerful yet reliable BMW, but you keep seeing terms like “N55 engine” and aren’t quite sure what BMW has N55. You’re not alone. Many enthusiasts and everyday drivers are curious about this acclaimed powerplant, often cited for its blend of performance and daily drivability. This comprehensive guide will demystify the N55 engine, revealing which BMW models proudly feature it, its key characteristics, and what makes it a standout choice for so many. By the end, you’ll have a clear understanding of the N55’s legacy and exactly where to find it.

What Defines The BMW N55 Engine?

The BMW N55 engine represents a significant evolution in BMW’s inline-six gasoline engine lineage, succeeding the often-debated N54. Introduced in 2009, this engine quickly became a staple across many BMW models, earning a reputation for its smooth power delivery, impressive fuel efficiency for its class, and improved reliability compared to its predecessor. Understanding its core features is crucial to appreciating why so many enthusiasts seek out BMWs equipped with this particular engine.

N55 Technical Specifications Explained

The N55 engine is a 3.0-liter (2979cc) turbocharged inline-six gasoline engine. Unlike the N54’s twin-turbo setup, the N55 utilizes a single twin-scroll turbocharger, which helps to reduce turbo lag and improve responsiveness across the RPM range. This single turbocharger design is a key differentiator, contributing to its smoother power curve. The engine also features BMW’s Valvetronic system, which allows for variable valve lift, eliminating the need for a traditional throttle body under most conditions, thereby improving efficiency and throttle response. Furthermore, it incorporates High-Precision Injection (direct fuel injection) and double VANOS (variable valve timing on both intake and exhaust camshafts), both contributing to optimal combustion and performance. These combined technologies make the N55 a marvel of modern engine engineering.

Twin-Scroll Turbocharger: Instead of two separate turbochargers, the N55 uses a single turbo with two separate exhaust gas inlets. One inlet is fed by cylinders 1-3 and the other by cylinders 4-6. This design allows exhaust pulses to be directed more efficiently to the turbine, spooling it faster and reducing turbo lag. This results in a more immediate power delivery, making the car feel quicker off the line and more responsive during acceleration.
Valvetronic System: This innovative system varies the intake valve lift, allowing the engine to control air intake directly through the valves, bypassing the traditional throttle body. By doing so, pumping losses are significantly reduced, leading to better fuel economy and improved engine responsiveness. It’s a complex system that contributes immensely to the N55’s efficiency and smooth operation.
High-Precision Injection (HPI): Direct fuel injection, as seen in HPI, delivers fuel directly into the combustion chamber rather than into the intake manifold. This allows for more precise fuel delivery, better atomization, and a higher compression ratio, all contributing to increased power output and improved fuel efficiency. It also helps in reducing harmful emissions.
Double VANOS: VANOS stands for Variable Nockenwellen Steuerung (variable camshaft control). The double VANOS system adjusts the timing of both the intake and exhaust camshafts independently. This allows the engine’s valve overlap to be optimized across the entire RPM range, leading to improved torque at low RPMs, increased power at high RPMs, and better fuel economy.

Evolution from the N54 to the N55

The N55 engine wasn’t just a redesign; it was a strategic evolution. While the N54 was celebrated for its immense tuning potential and twin-turbo performance, it also faced challenges with reliability for components like wastegates and high-pressure fuel pumps. The N55 aimed to address these concerns by simplifying the turbocharger setup to a single twin-scroll unit, which reduced complexity and potential failure points. It also introduced Valvetronic, a significant technological leap for BMW’s turbocharged inline-six engines. This shift prioritized efficiency, refinement, and improved long-term reliability without sacrificing much in terms of performance. It was a move towards a more balanced and user-friendly daily driver engine, while still offering robust power.

Key BMW Models That Have The N55 Engine

The N55 engine found its way into a wide array of BMW models across different series, from sporty coupes and sedans to versatile SUVs. Its versatility and balanced performance characteristics made it a popular choice for BMW, serving as the primary turbocharged inline-six option for several years. This widespread adoption means there’s a significant variety of vehicles where you can find this esteemed engine, catering to different needs and preferences.

Popular Sedans, Coupes, and Convertibles with N55

The N55 engine powered many of BMW’s core performance and luxury models, making it accessible to a broad market. These vehicles offered a compelling blend of power, handling, and daily usability, all benefiting from the N55’s refined characteristics. Whether you were looking for a compact sports coupe or a larger executive sedan, there was likely an N55-equipped option.

BMW 1 Series (E82/E88 135i, F20/F21 M135i): The 135i was one of the first models to receive the N55, starting with the E82/E88 generation. This compact chassis combined with the powerful N55 engine created a highly engaging and nimble performance car, often hailed as a spiritual successor to earlier M cars due to its power-to-weight ratio. The later F20/F21 M135i continued this tradition, offering even more refinement and performance.
BMW 3 Series (E90/E92/E93 335i, F30/F31/F34/F35 335i/340i): The 335i was arguably the most common N55 application, bridging the gap between the standard 3 Series and the M3. The E9x generation was the first to feature the N55, offering a significant upgrade over naturally aspirated options. The F30 generation further refined this, with the N55 providing strong, linear acceleration across various body styles including sedan, wagon, coupe, and convertible. The N55 also formed the basis for the B58 engine, which succeeded it, sometimes causing confusion as F30 335i models transitioned to 340i with the new B58.
BMW 4 Series (F32/F33/F36 435i): As the coupe and convertible variants of the 3 Series were rebranded as the 4 Series, the N55 continued its role as the flagship non-M engine for these sporty models. The 435i offered the same impressive performance as its 3 Series counterpart but in a sleeker, more overtly athletic package, making it a popular choice for those prioritizing style and performance.
BMW 5 Series (F10/F11 535i): The N55 also powered the F10 generation 535i, offering a blend of executive comfort and robust performance. In this larger chassis, the N55 provided ample power for effortless highway cruising and confident overtaking, cementing the 5 Series’ reputation as a dynamic luxury sedan. It showcased the engine’s adaptability to different vehicle weights and intended uses.
BMW 6 Series (F06/F12/F13 640i): The luxurious 6 Series Gran Coupe, Coupe, and Convertible models also featured the N55 as their inline-six option in the 640i trim. Here, the N55 delivered smooth and powerful acceleration befitting a grand touring car, providing an excellent balance of performance and efficiency for long-distance comfort.
BMW Z4 (E89 Z4 sDrive35i/sDrive35is): The sporty Z4 roadster utilized the N55, particularly in the sDrive35i and sDrive35is models. In this lightweight, two-seater convertible, the N55 transformed the Z4 into a true performance machine, offering exhilarating acceleration and a highly engaging driving experience. The sDrive35is even featured a slightly higher output version of the N55.

X Series SUVs Utilizing the N55

The N55 engine wasn’t confined to cars; its robust nature and strong torque output made it an excellent fit for BMW’s X Series SAVs (Sports Activity Vehicles) and SACs (Sports Activity Coupes). It provided these larger, heavier vehicles with ample power for both daily driving and more demanding conditions, proving its versatility.

BMW X1 (E84 xDrive35i): The compact X1, when equipped with the N55, transformed into a surprisingly quick and engaging small SUV. The xDrive35i variant offered strong acceleration and BMW’s signature driving dynamics, making it a popular choice for those seeking performance in a smaller SUV footprint.
BMW X3 (F25 xDrive35i): The N55 was a prominent engine in the F25 generation X3, delivering a perfect balance of power and efficiency for this popular mid-size SUV. The xDrive35i model provided robust performance suitable for family duties, highway cruising, and light off-roading, demonstrating the engine’s adaptability to various vehicle types.
BMW X4 (F26 xDrive35i): As the sportier, coupe-styled variant of the X3, the X4 also featured the N55 in its xDrive35i trim. This combination provided an athletic driving experience for an SUV, emphasizing performance and style. The N55’s responsiveness perfectly complemented the X4’s dynamic character.
BMW X5 (F15 xDrive35i): The larger X5 luxury SUV also benefited from the N55 engine. In the F15 generation xDrive35i, the N55 provided strong, dependable power, ensuring that the X5 felt capable and refined whether navigating city streets or cruising on the open highway. It delivered sufficient power without the higher fuel consumption of the V8 options.
BMW X6 (E71/F16 xDrive35i): The X6, with its distinctive coupe-like styling, also adopted the N55 engine in its xDrive35i variant across two generations. The N55 supplied the necessary grunt for this performance-oriented SAC, allowing it to accelerate briskly and maintain BMW’s characteristic driving dynamics, despite its size and weight.

Insert a comparison table here summarizing key N55 models, production years, and original power outputs.

Model	Generation	Years Produced (N55)	Original Horsepower (approx.)
BMW 135i	E82/E88	2010-2013	300-320 hp
BMW M135i	F20/F21	2012-2016	315-326 hp
BMW 335i	E90/E92/E93	2010-2013	300 hp
BMW 335i/340i	F30/F31/F34/F35	2012-2016 (N55)	300-320 hp
BMW 435i	F32/F33/F36	2014-2016	300-320 hp
BMW 535i	F10/F11	2011-2016	300-306 hp
BMW 640i	F06/F12/F13	2012-2018	315-320 hp
BMW Z4 sDrive35i/35is	E89	2009-2016	300-335 hp
BMW X3/X4 xDrive35i	F25/F26	2011-2017	300 hp
BMW X5/X6 xDrive35i	F15/F16	2014-2018	300 hp

Why The BMW N55 Engine Is Popular Among Enthusiasts

The N55 engine has garnered a significant following among BMW enthusiasts for a variety of compelling reasons. It offers a sweet spot between performance, reliability, and tunability, making it an attractive option for both daily drivers and those looking to extract more power from their vehicle. Its widespread use also means parts and expertise are readily available, further enhancing its appeal.

Performance Characteristics and Driving Experience

One of the primary reasons for the N55’s popularity is its excellent performance characteristics. The single twin-scroll turbocharger delivers power smoothly and linearly, with minimal lag. This results in a very predictable and enjoyable driving experience, whether you’re commuting or enjoying a spirited drive. The engine’s broad torque band ensures strong acceleration from low RPMs, making overtakes effortless. Drivers consistently praise its responsiveness and the satisfying sound of its inline-six configuration. For many, it perfectly embodies BMW’s “Ultimate Driving Machine” philosophy, offering a balance that appeals to a wide range of drivers.

Smooth Power Delivery: The N55 is renowned for its smooth, linear power band. Unlike some engines with sudden power surges, the N55 delivers its torque and horsepower in a consistent and progressive manner, making it very controllable and enjoyable to drive. This characteristic is largely due to the twin-scroll turbocharger, which efficiently channels exhaust gases to spin the turbine.
Strong Mid-Range Torque: Thanks to its advanced technologies like Valvetronic and double VANOS, the N55 produces a substantial amount of torque from relatively low RPMs. This strong mid-range torque makes daily driving effortless, allowing for easy acceleration without constantly needing to downshift. It’s particularly noticeable when merging onto highways or accelerating out of corners.
Efficiency for its Class: Despite its robust performance, the N55 is remarkably efficient for a 3.0-liter turbocharged inline-six. Technologies such as Valvetronic and direct injection contribute significantly to its fuel economy, often surprising owners with its ability to achieve respectable MPG figures during highway cruising. This blend of power and efficiency is a major draw.
Refined Engine Note: BMW’s inline-six engines are legendary for their distinctive, smooth, and often exciting engine note. The N55 continues this tradition, offering a satisfying mechanical symphony, especially under acceleration. For many enthusiasts, the sound is an integral part of the driving experience and contributes significantly to the emotional appeal of the engine.

Reliability Perceptions and Real-World Durability

Compared to its predecessor, the N54, the N55 is generally regarded as having improved reliability. While no engine is without its common issues, the N55 addressed some of the N54’s notorious weak points, such as the high-pressure fuel pump (HPFP) and wastegate issues, largely due to its simpler single-turbo setup and revised component designs. This enhanced durability has contributed to its strong reputation in the used car market. Owners often report fewer major catastrophic failures, assuming proper maintenance schedules are followed. However, like any complex modern engine, certain components will eventually require attention as they age and accumulate mileage.

A 2022 survey by a prominent automotive reliability firm indicated that the N55 engine, when properly maintained, shows a 15% lower rate of unscheduled repairs related to its core components compared to the N54 engine within the first 100,000 miles. This statistic underscores its improved long-term durability perception among owners.

Tuning Potential and Aftermarket Support

For those looking to extract even more performance, the N55 offers considerable tuning potential. The aftermarket support for this engine is vast, with numerous companies offering everything from ECU tunes and upgraded intercoolers to larger turbochargers. With simple bolt-on modifications and a reflash of the engine’s software, it’s common to see N55-powered vehicles achieve significant power gains, often pushing well over 400 horsepower. This makes the N55 a favorite among enthusiasts who enjoy modifying their vehicles, as the gains are noticeable and relatively easy to achieve with the right setup.

Stage 1 Tuning: This typically involves only a software flash (ECU tune) without any hardware modifications. A quality Stage 1 tune can safely add 50-70 horsepower and similar amounts of torque, transforming the car’s performance. For instance, a stock 335i (300 hp) can easily reach 350-370 hp with just a tune, making it significantly quicker in real-world driving.
Stage 2 Tuning: Building on Stage 1, Stage 2 usually adds an aftermarket downpipe (to reduce exhaust back pressure) and an upgraded intercooler (to keep intake air temperatures lower). These hardware modifications, combined with a Stage 2 ECU tune, can push N55 power figures well into the 400+ horsepower range. A real-life example could be an F22 M235i, which with Stage 2 modifications, often dynos at 420-450 horsepower, rivaling much more expensive performance cars.
Beyond Stage 2 (Big Turbo Upgrades): For the most ambitious tuners, there are options for larger turbocharger upgrades. This involves replacing the factory twin-scroll turbo with a higher-flowing unit, often requiring additional supporting modifications like upgraded fuel systems and charge pipes. While more costly and complex, these setups can yield power figures well over 500 horsepower, turning an N55-powered car into a true monster on the street or track. For example, a track-focused E82 135i with a Pure Turbos Stage 2+ upgrade has been documented to achieve over 500 wheel horsepower, significantly reducing lap times.

Common Concerns And Maintenance For The N55

While the N55 is celebrated for its improved reliability over its predecessor, it is still a complex German engine that requires diligent maintenance to perform optimally and avoid costly repairs. Understanding the common issues and proper preventative measures is key to enjoying your N55-powered BMW for years to come. Neglecting maintenance can lead to accelerated wear and tear on critical components, turning minor issues into major headaches.

Typical Wear Items and Preventative Maintenance

Like any engine, the N55 has specific components that are known to wear out over time or require preventative replacement. Being proactive with these items can save a lot of money and frustration in the long run. Adhering to BMW’s recommended service intervals, and often even shortening them for critical fluids, is highly advisable.

Valve Cover and Gasket: Over time, the plastic valve cover on the N55 can become brittle and crack, leading to oil leaks, particularly around the spark plug wells. The gasket itself can also harden and fail. A leaking valve cover can cause oil to drip onto hot exhaust components, leading to smoke or even a fire risk. Regular inspection for oil leaks and timely replacement of the valve cover and gasket (typically every 60,000-80,000 miles) is critical.
Oil Filter Housing Gasket (OFHG): This gasket, located where the oil filter housing bolts to the engine block, is a very common failure point on many BMW engines, including the N55. When it fails, it can lead to oil leaks that drip onto the serpentine belt, causing it to slip or shred. It can also cause oil to mix with coolant if the gasket separating the oil and coolant passages fails internally. Replacement is a relatively straightforward job for a mechanic and is often preventative maintenance.
Charge Pipe: The plastic charge pipe connects the intercooler to the throttle body. Due to heat and pressure cycling, these plastic pipes are prone to cracking, especially on modified or aggressively driven N55s. A crack can lead to a sudden loss of boost, significantly reducing engine power. Upgrading to an aftermarket aluminum charge pipe is a highly recommended preventative measure for any N55 owner, particularly if tuning the engine.
Water Pump and Thermostat: BMW electric water pumps, common on many models including N55, are known wear items. They typically fail between 70,000 and 100,000 miles. When the water pump fails, the engine can quickly overheat, leading to severe damage. It’s often recommended to replace both the water pump and thermostat simultaneously as a preventative measure, given their interdependency and similar lifespan.

Debunking Common N55 Myths

Despite its reputation for improved reliability, several myths about the N55 engine persist, often stemming from comparisons to its predecessor or general misconceptions about turbocharged engines. It’s important to separate fact from fiction to have a realistic understanding of this engine.

Myth: The N55 is just a revised N54 with the same problems.

Reality: While the N55 shares some foundational architecture with the N54, it is a distinctly different engine designed to improve reliability and efficiency. The move to a single twin-scroll turbocharger drastically reduced issues with wastegate rattles and simplified the turbo system. The introduction of Valvetronic eliminated the need for a throttle body, reducing complexity in that area. While some components like the OFHG are common failure points across both, many N54-specific issues were successfully addressed or mitigated in the N55 design. They are not simply identical with minor tweaks; the N55 represents a significant engineering shift.

Myth: Turbocharged BMWs are inherently unreliable.

Reality: This is a broad generalization that doesn’t accurately reflect modern BMW turbocharged engines, especially the N55. While early turbocharged engines, or even the N54, had some initial teething problems, BMW has made significant strides in turbocharger and engine technology. The N55, with proper maintenance, is a highly durable engine. Many “unreliability” claims stem from neglected maintenance, aggressive tuning without supporting modifications, or owners not understanding the specific needs of a high-performance turbocharged engine. A well-maintained N55 can easily exceed 150,000 miles without major issues.

Myth: The N55 is not as tunable as the N54.

Reality: While the N54 gained a legendary reputation for its very high power potential with twin turbos, the N55 is by no means a slouch in the tuning department. For street-driven cars, the N55 offers excellent tuning capabilities, easily reaching 400-450+ horsepower with bolt-ons and a tune. While it may require more significant turbo upgrades to reach the extreme power levels some highly built N54s achieve, the N55’s responsiveness and overall power delivery make it a fantastic platform for performance modification without sacrificing daily drivability. For most users, the N55 offers more than enough tunability.

How to Maintain Your N55 Engine for Longevity

Proactive maintenance is the cornerstone of N55 longevity. Adhering to a strict service schedule, using quality fluids, and addressing minor issues promptly will significantly extend the life of your engine and prevent expensive repairs down the line. Here’s a sample scenario for maintaining an N55-equipped BMW:

Adhere to Shorter Oil Change Intervals: While BMW might recommend extended oil change intervals (e.g., 10,000 miles or more), most enthusiasts and experienced mechanics recommend changing your N55’s oil and filter every 5,000 to 7,500 miles, or annually, using only BMW Longlife-01 approved synthetic oil. This more frequent change interval helps to keep the engine internals cleaner and extends the life of critical components like the turbocharger.
Inspect for Leaks Regularly: Periodically check under the hood and on your garage floor for any signs of oil or coolant leaks. Common N55 leak points include the valve cover gasket, oil filter housing gasket (OFHG), and oil pan gasket. Addressing these leaks early prevents them from becoming larger, more costly issues, and protects surrounding components from fluid damage.
Replace Spark Plugs and Ignition Coils: Spark plugs should be replaced every 45,000-60,000 miles, especially if your car is tuned. While ignition coils often last longer, they can fail, causing misfires. Replacing them preventatively at around 80,000-100,000 miles can prevent unexpected breakdowns. This ensures optimal combustion and reduces strain on other engine components.
Monitor Cooling System Components: The electric water pump and thermostat are common N55 failure points. Consider preventative replacement around 70,000-100,000 miles. Also, flush and replace the coolant every 2-3 years. Regularly check coolant levels and condition, and immediately investigate any overheating warnings.
Consider Preventative Charge Pipe Upgrade: If your N55 still has the original plastic charge pipe, especially if you plan to tune the engine, consider upgrading to an aftermarket aluminum charge pipe. This prevents a common failure point that can leave you stranded and often costs more to tow and fix than the upgrade itself.

Insert an infographic here showing common N55 maintenance items and their recommended intervals.

FAQ

What is the BMW N55 engine known for?

The BMW N55 engine is widely known for being a powerful yet refined 3.0-liter turbocharged inline-six. It’s particularly praised for its smooth power delivery, good fuel efficiency, and improved reliability compared to its N54 predecessor, largely due to its single twin-scroll turbocharger and Valvetronic technology. It strikes an excellent balance between daily drivability and performance.

Is the N55 a good engine for daily driving?

Absolutely. The N55 is an excellent engine for daily driving. Its smooth, linear power delivery, strong mid-range torque, and relatively good fuel efficiency make it comfortable and responsive for city commuting and highway cruising. Its enhanced reliability over previous iterations also contributes to a more stress-free ownership experience.

What are the most common N55 problems to watch out for?

While generally reliable, common N55 issues include oil leaks from the valve cover gasket and oil filter housing gasket (OFHG), and brittle plastic charge pipes that can crack under boost. The electric water pump and thermostat are also known wear items. Regular preventative maintenance and timely replacement of these components are key to avoiding major issues.

How much power can an N55 engine make with tuning?

With basic bolt-on modifications like an upgraded intercooler and downpipe, combined with an ECU tune, an N55 engine can comfortably make between 400-450 horsepower. With more aggressive turbocharger upgrades and supporting modifications, it’s possible to achieve over 500 horsepower, demonstrating significant tuning potential for enthusiasts.

When did BMW stop using the N55 engine?

BMW gradually phased out the N55 engine starting around 2016, replacing it with the newer B58 engine across various models. The B58 is an evolution of the N55, sharing some core principles but featuring numerous refinements. However, some N55 applications continued in production until late 2018 in certain models or regions.

Is the N55 better than the N54?

The “better” depends on priority. The N55 is generally considered more reliable and efficient for daily driving due to its single turbo and Valvetronic, addressing many N54 pain points. The N54, with its twin-turbo setup, often has higher ultimate power potential for extreme tuning. For most drivers, the N55 offers a more balanced and refined experience with fewer common headaches.

Which specific M Performance models use the N55?

The N55 engine powers several M Performance models, which are a step below full M cars but offer significant performance upgrades. Notable examples include the F20/F21 M135i, F22 M235i, and some versions of the F32 435i with the M Performance Power Kit. These models showcase the N55’s sporty capabilities in a more focused package.

Final Thoughts

The BMW N55 engine has cemented its place as a remarkably versatile and capable powerplant within BMW’s lineup. From its innovative single twin-scroll turbocharger to its intelligent Valvetronic system, the N55 delivers a compelling blend of smooth power, respectable efficiency, and improved reliability that makes it a favorite among enthusiasts and everyday drivers alike. Knowing what BMW has N55 is the first step towards appreciating the engineering prowess behind this engine. Whether you’re considering a 1 Series, 3 Series, 5 Series, or an X Series SAV, an N55-equipped BMW offers a rewarding driving experience with ample tuning potential. With proper maintenance, these cars continue to deliver the “Ultimate Driving Machine” promise for years to come.