N54 vs N55

[Dackelone]

engine

N54 = forged crankshaft
N55 = cast crankshaft

N54 = Mahle pistons
N55 = Mopisan (Turkish) pistons



suspension:

N54 = progressive rear springs
N55 = linear rear springs


Note: I attached some BMW pdf's on the N55 and N54 engine's for your viewing pleasure.

[Vectors2final]

After doing some research, Mahle owns Mopisan

http://www.mahle.com/C12572E60048082...GTKHL749STULEN


Mopisan was originally an aftermarket producer of pistons/components etc.. Who's to say they aren't made well or cannot handle the power. You don't know that for sure, and you don't know how much Mahle has had in the production of the pistons. After reading, it looks like Mahle has a lot to do with the production because their work load was getting large and needed to expand. You also cannot say that just because they are made in Turkey means anything because if Mahle pistons were produced in Turkey, you'd think they were from Germany. BMW can be a little foolish at times, but not that foolish.

[rader1]

How about just post listing the differences between the two engines? Not personal opinions, but just a just a list of differences in parts/designs/manufactures. Ofcoarse, I'm opting myself out of compiling this list..

[Vectors2final]

More to follow, but this is reallllll good info on the Vs.

[Vectors2final]

[Vectors2final]

More to follow....


I am doing this because most of you won't read the PDF Dackel posted anyways, and this provides a lot of comparisons to both.

[Turbolader]

(Thanks Dackel) Here's the differences I can find. IMO, the differences are "evolutionary" with exception of the Valvetronic system and much simpler oiling system. I have a feeling the N55 is going to be easier on oil than the N54.

N54: Some cams are cast, some are lightweight hollow
N55: All cams are lightweight hollow

N54: Vacuum pump gets oiled by unfiltered oil
N55: Vacuum pump gets oiled by filtered oil

N54: Connecting rods (small ends) do not have a hole
N55: Connecting rods (small ends) have a hole (Which distributes load better)

N54: Crank is forged, weighs approx 23.3Kg
N55: Crank is case, weighs approx 20.3Kg

N54: PCV system uses "cyclonic separators"
N55: PCV system doesn't use them

N54: No Valvetronic system (More complex oiling system)
N55: Valvetronic system, with simplified oiling system

N54: Intake valve size: 31.4mm, Lift is 9.7mm max
N55: Intake valve size: 32.0mm, Lift is 9.9mm max

(exhaust valve size/lift values are the same)

N54: Less span on intake/exhaust duration
N55: more span on intake/exhaust duration

N54: VANOS units are heavier (possibly not Al), and slower adjusting
N55: VANOS units are lighter (Made from Al), faster adjusting, simplified oiling

N54: BMW Piezo high pressure (HPI) multi-hole fuel injectors
N55: Bosch solenoid-valve fuel injectors (HDE) multi-hole are used

N54 & N55: Use same HPFP, Pressure sensor & fuel rail

N54: Dual mass (heavier) vibration dampener for crank
N55: Single mass (lighter) vibration dampener for crank

N54: Diverter valves are operated pneumatically
N55: Diverter valve is operated electronically

N54: Four catalytic converters are used
N55: two catalytic converters are used (two "bricks" are inside the single canister)

N55: PCM "DME" is mounted directly to intake manifold, and is cooled by intake air.

N55 has newer ignition coils.

N55 has newer oil pressure sensor that reads absolute pressure (N54 reads relative pressure)

N55 has a newer more accurate O2 sensor

N55 uses a Mass airflow sensor, N54 does not.

[Lee123]

Originally Posted by Vectors2final

More to follow, but this is reallllll good info on the Vs.

Thanks for posting this. It is very interesting. Is the source document available online somewhere? I'd like to save a copy and that would be easier than saving all the individual pages as images.

[Vectors2final]

[Vectors2final]

Originally Posted by Lee123

Thanks for posting this. It is very interesting. Is the source document available online somewhere? I'd like to save a copy and that would be easier than saving all the individual pages as images.

Dackel posted it above, but I decided to let everyone see because half will still talk, not even read. Plus, I can host all of these no problem..

[Dodo]

Originally Posted by Turbolader

(Thanks Dackel) Here's the differences I can find. IMO, the differences are "evolutionary" with exception of the Valvetronic system and much simpler oiling system. I have a feeling the N55 is going to be easier on oil than the N54.

...(Snip)...

Great info, but I don't see it making much difference. N55 loyalists will scream about lighter weight/rotating mass and that theirs is more advanced and N54 fans will yell about how theirs is stronger and simpler....
I guess people can't just be happy that they have a great engine, it has to be "Better than yours".

[Vectors2final]

[Vectors2final]

I'm just going to keep it coming because there is a lot more info...

[Impervious]

Just to sum things up...


Both are fantastic engines and there really isn't enough of a difference to matter. You can't go wrong so don't worry about it.

[Vectors2final]

[Vectors2final]

[Vectors2final]

That pretty much sums it up, and I haven't read all of it yet, but enjoy seeing it all here..

[blacknbean]

Originally Posted by Aries932

/sigh...did you even bother to read over this years awards?

yup. directly from the award site. bmw twin turbo! they also go on to mention the 1M. n55 != twin turbo http://www.ukipme.com/engineoftheyea...s_11/25_3.html

[Mikeshot1]

Lots of good info. Read quite a bit. I have an N54 and read somewhere peak boost is 8.8psi, is the N55 the same?
Before this read I only knew the N55 reached peak boost at 1200 rpm
As opposed to 1400 and that it was a twin scroll which means there's 2 up pipes for quicker turbo spool if my STi day memory is correct.
Also, does anyone know the sizes of the N54 and N55 turbos? For example my Forced Performance Green turbo had a 49 lb wheel on cold side and had an 8cm on the hot side.
You'd think with the great BMW engineers the N55 would be better in almost every way, but there's always cost savings and sounds like one of them was the cast crank.

[Focusedintntions]

Fantastic posts guys!

[Aries932]

Originally Posted by blacknbean

yup. directly from the award site. bmw twin turbo! they also go on to mention the 1M. n55 != twin turbo http://www.ukipme.com/engineoftheyea...s_11/25_3.html

First let me say this is probably the most constructive N54 vs. N55 thread I have seen to date. Everyone is coming with actual facts and not just ridiculous statements.

As for the award site the link you posted is the engine in the 1M which yes is the N54, but it seems as though they have put the 1M N54 and the N55 together in that award because if you look at the other cars listed some of them are only the N55....like the X6 35i, the 335i 2011, x5 35i, x3 35i, 740i for example is the 300hp N55.

[rader1]

So, there you go!! They're both the best lol