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 The BMW N54 engine was superseded by the N55, which debuted in the F07 5 Series Gran Turismo.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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I originally posted this on the BMW forum, but I thought I’d give it another shot here.
I want to know this since I think the N55 single turbos have had less trouble with the HPFP than the N54. But maybe someone could shed some light on this for me.
Unfortunately, HPFP troubles are not eliminated by the N55, but reportedly in Canada they are a BMW warrantied part for 10 years or 200,000 miles (albeit you will undoubtedly have to pay the labor costs).
Basically, if the vehicle is a 2010 or 2011, it is a N54 (dual turbo), and vice versa (single dual scroll turbo). However, BMW did produce some N55s alongside N54s in the months of September, October, and November of 2009, and then again in February of 2010. (both engines were being used) So, a late-model vehicle could have either engine. That is a rare instance, though. As I already stated, all 2010s are N54s, and all 2011s are N55s. In February 2010, N55 SOP (start of production) began. The newest HPFP design wasn’t released until May or June of that year (i believe).
My tuner informed me that the HPFP WILL fail, not IF, but WHEN, IF it is produced by Bosch. If you own an HPFP built by Conti, they appear to hold up nicely. In any case, certain N55 engines have had HPFP problems.
I sincerely appreciate it. This is the reason I was perplexed! Although I had read that the N55 and N54 were occasionally mixed together during production runs, I was unable to determine whether a full transition had actually been made. This explains everything!
Comparison of the horsepower, dependability, and tunability of the BMW N54 and N55
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.
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.
Twin-turbo N54
On the other side, the twin-turbo N54 performs better with the identical modifications than the N55. This is because the N54 benefits more from modifications because it can move a lot more air.
However, twin-turbo systems like the N54 are substantially more intricate, expensive, and huge. It explains why single-turbo installations are preferred among auto tuners. For more power, they are simpler to modify.
However, because of its more effective turbo system, the N55 boasts 15% better fuel efficiency and fewer emissions.
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.
Key distinctions between N54 and N55
The type of turbocharger utilized in each engine is the primary distinction between the N54 and N55.
A
While the N55 has a single turbo with a twin-scroll exhaust, its N54 engine uses two turbos. A twin-scroll turbocharger has two exhaust housings instead of one, making it a conventional turbocharger.
The distinction between this engine and other regular engines is that the turbo features a scroll to reduce exhaust reversion for each set of three cylinders that fire on the same cycle. The twin-scroll configuration enables the engine to reach its maximum torque at 100 fewer revolutions.
Road Sumo claims that the twin-turbo N54 outperforms the twin-scroll N55 because it can move more air while operating. In contrast to the N55, which has an electronic actuator, it is comprised of two turbochargers.
The connecting rods and crank used by the N54 are forged, while those used by the N55 are cast. As a result, the N55 engine is significantly lighter than the N54 engine.
And unlike the HPI injectors utilized in the N54, the N55 uses Bosch solenoid valves. The N55 injector is more dependable and less expensive despite the piezo-style HPI burning more efficiently.
Do I have N54 or N55 in my BMW?
I own a 2011 135i with a pre-09/10 build date. Is it as straightforward as anything 2011+ is n55, or is there a quick way to determine whether I have n54 or n55?
In reality, BMW began producing the N55 in September 2009. They produced some alongside the N54 but not many. Thus, choosing an engine only based on build date is not guaranteed.
For these production months, BMW began producing “some” N55s in addition to the regular N54 output:
The best approach to determine whether an automobile is a N55 is probably to see if it has a DCT. It is a N54 if it has a car. If it’s a 6MT, you’ll need to examine the engine. See the images shown above to identify the different engines.
In addition, to respond to the OP’s initial query regarding his Sept. 2010 construction date, I can confirm that your engine is a N55.
What models of BMW have N55 engines?
The use of the N55 is indicated by the “35i” badge following the model name, as opposed to a “28i,” which indicates that it is powered by a four-cylinder engine. The BMW M2, which used the N55 until it was updated with the S55 M engine, and the 6 Series and 7 Series, which use the “40i” designation, are exceptions.
- 2009-2017: 535i
- 2010-2013: 335i
- 2010-2013: 135i
- X3 xDrive35i from 2010 to 2017.
- X5 xDrive 35i from 2011 to 2013.
- 2011-2015: 335i
- X6 xDrive 35i from 2011 until 2014.
- X1 xDrive35i from 2012 until 2015.
- 2013-2016: 435i
- X5 xDrive 35i from 2014 to 2018.
- X6 xDrive35i from 2014 to 2019.
- X4 xDrive 35i from 2014 to 2016.
- 2013-2016: M235i
- 2012-2015: 740i/Li
- 2011-2018: 640i
- 2016-2018: BMW M2
How trustworthy is N55?
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.