2009 saw the start of manufacturing for the BMW N55, a straight-six petrol engine with turbocharging. The BMW N54 engine was superseded by the N55, which debuted in the F07 5 Series Gran Turismo.
First straight-six engine from BMW to use a twin-scroll turbocharger was the N55. Additionally, from 2011 to 2013, it earned three in a row from Ward’s 10 Best Engines.
The N55 engine started to be phased out in 2015 after the debut of the BMW B58 engine.
The N55 engine, which powers the F80 M3, F82 M4, and F87 M2 Competition/CS, is upgraded into the BMW S55 by BMW M GmbH.
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The S55 Engine’s Past
The BMW N55 engine serves as the foundation for the S55. The BMW 5 Series Gran Turismo introduced the first N55 engine in 2009. The N55 and S55 have the same bore (84.0 mm), stroke (89.6 mm), and displacement (2979 cc). Both engines have a 10.2: 1 compression ratio as well.
Aiming to blend the benefits of a high-performance, naturally aspirated engine with those of contemporary turbo technology, BMW M GmbH worked with both the old and the new systems when developing the newly created in-line 6-cylinder engine.
The impacts on the responsiveness of the M3 and M4 models are clear: the 3.0-liter engine’s potential is demonstrated with 431 horsepower and a maximum rpm of 7,600. with a 550Nm maximum torque starting at 1,850 rpm. Fast sprints can now be completed in less time than ever before, and the 7-speed M dual-clutch transmission can now accelerate from 0 to 100 km/h in just 4.1 seconds. The engine had already shown itself to be more effective than its forerunners.
6-cylinder BMW S55 engine
The BMW S55 is an inline six-cylinder engine that expands upon the BMW N55 and features twin turbo charging. The new BMW M3 (F80) and BMW M4 (F82) were released in the middle of 2014. The final BMW M3 (E90) generation marked the conclusion of the high-performance intake engine era at BMW. This M3’s predecessor used a four-liter, 309 kW (420 horsepower), high-speed V8 engine ( BMW S65 ).
The new six-cylinder outperforms it in terms of torque and fuel consumption at conditions other than full load; in typical traffic, two to three liters less fuel will be used.
The S55 shares the same bore and stroke measurements as the N55, as well as having an aluminum crankcase. However, the closed-deck construction of the N55 gives it greater rigidity and the ability to operate at higher combustion pressures; unlike its base model, the S55 also has a water intercooler mounted on the motor’s top in addition to the two turbochargers.
Along with the crankcase being constructed of aluminum, the following three features contribute to weight reduction: the cylinder liners are sprayed with electric arc rather than inserts; the cylinder head is also made of aluminum; and the oil sump is made of magnesium. The steel crankshaft is forged and hardened. Ultimately, the speed is 7600 min -1.
The two overhead camshafts are controlled by VANOS, which now allows for faster adjustments, and the exhaust valves are sodium-filled, exactly like on the N55.
In the BMW M4 GTS (2015)’s most potent variant, which has 368 kW (500 horsepower), water injection is used.
Since 2016, the extra Competition package has been made available for the BMW M3 (F80) and BMW M4 (F82), increasing the S55’s performance to 331 kW. (450 hp).
The S55 engine is included with the BMW M2 “Competition” Coupe, which has been available since September 2018. Here, it produces 302 kW (405 horsepower) and 550 Nm (406 lbf * ft) of maximum torque. BMW also employs the S55 to enable the M2 to adhere to higher emission standards.
Performance, dependability, and tuning in the BMW S55 and S58
With the introduction of the S55 in 2013, BMW permanently abandoned the market for natively aspirated performance motors in M-series vehicles. The 3.0L twin-turbocharged inline-6 S55 motor replaced the NA V8 S65 engine. The S55 includes a closed deck block, dual turbos, forged pistons, a lightweight crankshaft, and dual high pressure fuel pumps, to name a few differences, while being the performance variant of the N55.
Although the S58 won’t be officially released until Q4 2020, it is well known that it will be the following motor to power the M3 and M4 cars. However, the X3M and X4M cars for the 2020 model year already have the S58 on the road. The 3.0L twin-turbocharged inline-6 engine of the S58, which is based on the B58TU engine, is extremely similar in displacement to the inline-6 engine in the S55.
While the G80 M3’s speculated appearance is god terrible (we hope BMW reads this), the S58 engine has a lot more to offer. So how will the S58 compare to the S55 in terms of efficiency, dependability, and scope for customization?
General Opinions of the BMW N55
Even though it doesn’t receive the best reviews for dependability, the N55 isn’t a particularly unreliable vehicle. It serves as a stronger evidence to how excellent the two remaining engines are. The B58 and S55 engines from BMW are more recent, therefore more problems could develop in the future. The N55 has been on the road longer than the two previous engines, providing for more opportunity for tuning advances. Although there are more tuning choices available, the N55’s single turbo architecture restricts its ability to be tuned in comparison to the S55’s twin turbo design. The N55 offers an outstanding balance between dependability, purchase price, and total tuning possibilities, placing it only behind the N54 in terms of value.
What models of BMW have S55 engines?
Several contemporary BMW models, notably the F87 M2, F80 M3, and the F82/F83 M4, are equipped with the S55. With the above cars’ Competition packages, more powerful versions of this engine with higher specifications were available.
The BMW S55 engine’s dependability
Six years of on-road data suggest that the S55 is a very dependable motor. The crank hub was cited as a high-failure area on pre-2016 engine models, leading to a “spinning” crank hub. A firm called TPG tuning, which was attempting to sell more of their aftermarket crank hubs, used a fear technique to exaggerate the crank hub problem. While the S55 crank hub can and has failed on factory S55 vehicles, it is a very isolated issue that was fixed by BMW in 2016. The S55 crank hub is the same design as the N54 and N55.
Aside from this exaggerated problem, the S55 seems to be a durable engine. There are a few minor problems that affect all BMWs, such as HPFP failure and carbon build-up, but nothing that should cause any prospective buyers to hesitate.
The S55’s astonishing and unparalleled power-reliability ratio is unmatched by any other BMW engine.
What B58 models are available?
In 2015, the BMWB58 turbocharged straight-six engine went into production. The N55 was replaced by the B58, which debuted with the F30 340i.
Following the B38 and B48 engines, the B58 is a member of BMW’s new modular engine family, which includes engines with 500 cc (30.5 cu in) of displacement per cylinder.
The B58 engine, which is found in the 340i and 440i, was designated one of the world’s ten best engines in 2016, in 2018, in 2022 (M240i), in X3 and X4 M40i, in Z4 M40i, in 2019 (X5), and in 2020 (M240i) (M340i).
The high performance variant of the B58 engine is the S58, which debuted in early 2019.
BMW S55: Is it twin-turbo?
It might be said that the S55 is essentially an improved N55. The S55 has two conventional turbochargers, in contrast to the N55 from BMW, which only has one turbocharger with “TwinPower” technology (a turbocharger that is operated twice by two different exhaust manifolds). The M engine’s engine block structure is also more intricate. As a result, it can produce a class-leading 141 horsepower per liter of displacement, low CO2 emissions, and excellent throttle response.
The engine has a lot of new features and differs from the original model in various technical ways. However, when it comes to the crankcase or the extremely unique form of liner coating, the genes from BMW are indisputable.
The closed-deck design of the crankcase is one of the primary differences. The higher cover plate rigidity, which benefits both the cylinders and the acoustics, is the advantage of this unique design over the open-deck design. Furthermore, greater cylinder pressures and improved power production can be obtained.
It is important to note, however, that the S55 is not the only engine with a closed-deck crankcase; several BMW series engines and engines from other manufacturers also have this feature.
Even at low engine speeds, the throttle response is considerably increased thanks to the double Vanos, gasoline direct injection HPI, and variable valve management (Valvetronic). 370 lb are attained by the turbocharged engine. Ft of torque, a 30% increase over what it’s predecessor could muster. The fuel usage is also lowered by 25% at the same time.
When did the M2 receive the S55 engine?
At the 2018 Beijing Auto Show, the BMW M2 Competition made its debut as the more potent version of the normal M2 Coupe. Production first started in July 2018 and was completed in early 2019.
The BMW M GmbH S55 engine, a high-performance variation of the N55 engine that was detuned from its use in the F80 M3 and F82 M4, is used in the M2 Competition. Europe chose the Worldwide Harmonized Light Vehicles Test Procedure as the official method to assess vehicle pollutants, which meant that the regular M2’s N55 engine no longer complied with European emission rules, leading to the decision to use the S55 engine.
The S55 engine has a closed-deck engine block, a lightweight crankshaft, different crankshaft bearings, strengthened pistons and rods, different springs and valve material, twin turbos, twin fuel pumps, active exhaust, a revised cooling system, and intercoolers. These features set it apart from the N55 engine found in the standard M2.
The engine also has a revised oil delivery system, updated cooling system, and components from the BMW M4 Competition Package for the electronic locking differential. In some nations of the European Union, it also has a gasoline particle filter to cut pollution. The S55 generates 30 kW (40 hp) and 85 Nm (63 lbft) more than the normal M2, giving it a greater and more consistent power output of 302 kW (405 hp) between 5,250 and 7,000 rpm and 550 Nm (406 lbft) at 2,350-5,200 rpm. Vehicles with a six-speed manual transmission accelerate from 0 to 100 km/h in 4.4 seconds, while models with a seven-speed dual clutch transmission accelerate in 4.2 seconds. The M Driver’s package can increase the top speed from the electronically limited 250 km/h (155 mph) to 280 km/h (174 mph), which is 10 km/h (6 mph) faster than the M2’s top speed.
The M2 Competition has larger kidney grilles, optional larger brake discs that measure 400 mm (15.7 in) in the front axle with 6 piston calipers and 380 mm (15.0 in) in the rear axle with 4 piston calipers, as well as the standard carbon-fibre reinforced plastic strut bar found in all models equipped with the S55 engine. The M2 Competition weighs 75 kg (165 lb) more than the original M2, which had 1,550 kg (3,417 lb) for manual transmission models and 1,575 kg (3,472 lb) for dual-clutch gearbox models due to the engine and cooling system that were taken from the F82 M4.
What engine powers a BMW M4?
There are four main model variations of the 2023 BMW M4 Coupe. The 3.0 liter BMW M TwinPower Turbo inline 6-cylinder gasoline engine found in the M4 Coupe, M4 Competition Coupe, and M4 Competition xDrive Coupe can produce up to 503 horsepower. The 3.0 liter BMW M TwinPower Turbo inline-6 cylinder engine in the Limited Edition BMW M4 CSL produces 543 horsepower.