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 The BMW N54 engine was superseded by the N55, which debuted in the F07 5 Series Gran Turismo.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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BMW Straight-6 Engine N55 S55
The BMW N55 is a six-cylinder in-line DOHC engine with four valves that is turbocharged by BMW. It is BMW’s first twin-scroll turbocharged engine with a Valvetronics system and direct injection, and it debuted at the end of 2009 in the BMW 5 Series Gran Turismo (535i GT). This technology is known by BMW as BMW TwinPower Turbo. Its replacement, the BMW B58 modular engine, debuted in 2015.
Similar to its predecessor, the engine with two overhead camshafts features an aluminum crankcase (engine block) with an open deck and bedplate design. The N54’s forged crankshaft weighs 3 kg more than the cast iron, N54-made crankshaft. The aluminum cylinder head is composed of. The diameter of the intake valves is 32.0 mm, while the exhaust valves are filled with sodium.
The N55 has only one turbocharger, the so-called twin-scroll loader, which has two distinct spirals that lead the exhaust flow to the turbine wheel, which is an improvement over the earlier engine N54 B30, which had two turbochargers. On the N54, three cylinders were each in charge of one turbocharger; on the N55, three cylinders are in charge of each of the two spirals that drive the turbocharger. As opposed to the preceding N54 model, this turbocharger design weighs 4 kg less.
The turbocharger with direct injection and Valvetronic was initially combined with the N55, which is another novel development for the twin-scroll turbocharger. The throttle valve is unnecessary thanks to valvetronic, which regulates the lift of the intake valves in an infinitely variable manner. However, this is unnecessary. Thus, the air mass supplied for combustion in the engine itself is under the control of the Valvetronic. Combining these three techniques has lowered fuel usage even more and increased the N54’s reaction.
The engine is offered for BMW M vehicles as a performance version BMW S55 with up to 368 kW. (500 hp). Water injection is used on the M4 GTS’s most potent version.
The N55 differs from its N54 predecessor in that it employs a single twin-scroll turbo instead of two, and it also has variable valve lift (called Valvetronic by BMW).
The S55 engine, which is the N55’s high performance variant, powers the F80 M3 and F82 M4.
The N54 engine in several BMW vehicles was superseded with the N55 inline-six turbocharged engine. We evaluate the dependability and performance of the N55.
BMW is known for its inline-six engines, but turbocharging didn’t start with the N54’s introduction to production in 2006. BMW released the N55 as a replacement in 2009, three years later.
The N55, which features a single turbo instead of the N54’s dual turbo, is more efficient while still producing the same amount of power and torque. They have the same 10.2:1 compression ratio, as well as the same displacement, bore, and stroke.
There were two significant changes, though. The Valvetronic system underwent the first change. According to Dust Runners Automotive Journal, which offers some comprehensive information on the system, “Both the N54 and N55 use BMW’s VANOS system on both the intake and exhaust camshafts, but only the N55 uses the Valvetronic system which allows for variable lift control.”
The fuel injectors underwent a second upgrade, moving to a lower-pressure, less expensive Bosch system. A single, twin-scroll turbocharger has various benefits over a twin-turbo arrangement, including being simpler to package, less expensive to produce, more efficient, and more dependable. Nevertheless, the N55 produces 20 more horsepower while using less gasoline than the N54 did.
Why use an I-6 design? The automaker claims that having the intake on one side of the engine and the exhaust manifold and turbocharger on the other is the optimal layout for a turbocharged engine, according to Wards Auto. In contrast, a “V” engine requires air to be pumped to both rows of cylinders, which requires a more complicated design and greater packaging area.
So, which is better—a single turbo or two turbos?
The N54 and N55 engines from BMW are quite comparable to one another and practically operate identically when stock. Although either turbo set-up spools rapidly and produces outstanding power throughout the low end and midrange, the N55 twin-scroll turbo gives a slightly faster turbo spool and delivers peak torque 100 RPM’s sooner than the N54. However, this difference is negligible. The N54 is the more effective engine mod-for-mod because of its two turbos and forged internals. The N55, however, has emerged as the more dependable engine. N54s are infamous for having frequent troubles, especially in the beginning, although these problems have since been fixed. The N54 and N55 are unlikely to be at the top of your list if you’re searching for an all-around dependable vehicle.
Although I’m sure you already knew that before even clicking this page, our choice is N54.
Performance & Reliability of the BMW N54, N55, B58, and S55
BMW has been improving on the design of the turbocharged, direct injected inline 6 engine ever since the twin turbo N54 debuted on the market in the 2007 BMW 335i. The 335i received an improved N55 engine in 2010, then a B58 engine in 2016, but the name of the car was changed to 340i. Naturally, the turbocharged inline 6 was introduced in the F80 BMW M3 starting with the 2015 model year due to its success. None of these BMW turbo sixes are something to snarl at; with a tune and simple bolt-ons, they can all deliver enormous power figures. Additionally, they feature broad power and torque bands and little turbo lag, both of which result in quick low-end torque. Comparing the BMW N54, N55, B58, and S55, how do they compare?
Which engine is superior, the N54 or the N55?
According to Dust Runners Automotive Journal, the N55 performed better in terms of dependability. The N54 occasionally experiences problems with the high-pressure fuel pump, the electronic water pump, and the fuel injectors. The N54, however, offers superior performance in terms of improved throttle response and lower rpm torque.
On the other hand, if you opt to alter the N54, the twin-turbo arrangement delivers better performance. However, compared to the twin-scroll system, it costs more and occupies more room.
The N54 is your best option if you’re seeking for later tweaks or performance. However, the N55 is the best option if you want a dependable, cleaner engine.
The 535i, 335i, X3, X4, and X5 XDrive35i, 640i, ActiveHybrid 3 and 5, and S Bi-Turbo Edition 99 all make use of the N55. On the other hand, the 335i, 535i, 135i, and 740i all use the N54 engine.
BMW N54 N55 Background
The N54 engine first made an appearance in the 2006 E92 335i before being made available across the whole BMW lineup over the next three years. The majority of N54-powered cars are equipped with the twin-turbo straight-six, which debuted with 306 horsepower and 295 pound-feet of torque. The F01 740i and US-only E92/3 335is also had a 326 horsepower version of the engine, which also received 332 pound-feet of torque. The most potent models of the engine were the E82 1M Coupe and E89 Z4 sDrive35is, which produced
The power and torque statistics of the N55, which replaced the N54 in 2009, were the same as those of the N54 but peak torque came 100 rpm faster. The N55 also replaced two turbos with a single, bigger turbo. As BMW fitted the N55 to practically every model, there were many more variations of the N55 than there were of the N54. The 320hp version with 332lb ft was sent to the F-range 640i, US-only E82/8 135is, F20/1 M135i, and F01 740i; the 326hp version was delivered to the F22/3 M235i and LCI M135i; and the 340hp N55 was delivered to the F30 ActiveHybrid 3. The F87 M2 had the most potent version of the engine, with 370 horsepower and 369 lb-ft of torque, while the F26 X4 M40i had a 360 horsepower version with 343 lb-ft of torque.
What Is Basic
To recap some fundamentals, the 3.0L straight-six engine in the BMW N55 is made entirely of aluminum and has dual overhead cams, variable valve timing, and variable valve lift. The bore is 84mm, and the stroke is 89.6mm.
The total displacement now stands at 2,979cc. The BMW N54 before it had the same 10.2:1 compression ratio, as well as the same displacement, bore, and stroke.
The N55 was utilized in a number of different applications, including the 135i, 335i, 535i, X1, x3, x5, 640i, 740i, and M235i. Its use in practically every BMW model, from compact coupes to substantial SUVs, is evidence of the engine’s adaptability.
Power output varies depending on the particular model you’re looking at, from 302hp and 295lb-ft all the way up to 365hp and 369lb-ft.
Some of you might be thinking—and you’d be correct—that the 302 to 365 horsepower that a contemporary 3.0l turbocharged engine produces isn’t much.
Given the displacement and turbocharged nature, it’s not much, but what’s inside the N55 is what counts, and in the end, BMW wasn’t attempting to create some wacky record-breaking engine.
When did BMW install the N55 engine?
It’s crucial to take into account the variations between the N54 and N55 powered BMWs before making a decision on a turbocharged 135i, 335i, or 535i. The BMW 335i was the first vehicle to use the N54, which originally went into production in 2006; the N54 was then debuted in 2008 alongside the 135i and 535i. BMW’s N55 engine started being produced in 2009, and it began to phase out the N54 in 2010. However, the dual turbo N54 was still used in the majority of applications created in 2010. In 2011, the N55 formally superseded the N54 (with the exception of the 1M and Z4 35i). Although there are numerous similarities between the engines, this piece will focus on their main distinctions.
Is the BMW N55 a reliable motor?
Despite widespread assumptions to the contrary, the BMW N55 engine is actually a quite reliable one. In no particular order, the valve cover and gasket, water pump, oil filter housing gasket, and VANOS solenoids are the four most frequent issues with the N55. The majority of the parts are inexpensive, and none of these are particularly serious problems. However, if you consistently service your car at the BMW dealership or independent repair shops, the repair costs might start to mount, and I believe this is where the myths about BMW reliability come into play.
Also, bear in mind that this is not a comprehensive list of potential issues with the N55; just because something is on the list does not indicate that it will always be a problem. The “average” N55 and what goes wrong with the “average” engine are the subjects of our investigation. Many N55s with 100,000 miles have not required any out-of-pocket spending on repairs, but others with many fewer miles may do so at a cost of thousands each year. It all comes down to how well you take care of your N55, as well as some random chance. In general, the BMW N55 engine is a dependable one that is simple to tune to produce excellent horsepower and torque.
When was BMW N54 released?
From 2006 through 2016, BMW developed the N54, a twin-turbocharged straight-six petrol engine. Since the 1986 discontinuation of the BMW M106’s restricted manufacturing, it is BMW’s first turbocharged gasoline engine that is mass produced. The N54 was introduced in the 335i model of the E90/E91/E92/E93 3 Series lineup during the 2006 Geneva Motor Show.
The N54 started to disappear after the 2009 debut of its BMW N55 replacement. The E89 Z4 roadster, which was built until 2016, is the last vehicle to be powered by the N54.
Although the N54 does not exist in a BMW M configuration, it is used in the 1 Series M Coupe, 135iS, Z4 35iS, and 335iS vehicles.