[mcnevin]

Feel free to correct me if I'm wrong and not sure if this has been brought up before.

For a laugh, I was doing research into whether the water intercooler from M4 would fit on our m2, since the s55 is based off the n55 and share 75% of parts(thats on the base n55 not the m2's) So I was reading all 3 engine techincal docs (n55, m2's n55 and the s55)

And found the following.

In the s55's tech doc it states "Modified for bi-turbo Closed Deck Design" under Crank Case Page 12 under the comparing the n55 and the s55 part. So since BMW took the closed deck design from the m2 tech doc and everyone is crying over who is right or wrong. So i'm going ahead ask is the s55 really a closed deck engine?? Someone else made this comment somewhere, just because something is design like something doesnt mean it is. So I ask is the s55, since both n55 and s55 and very closely related.

Second thing I'm going to point out, read the m2's engine tech doc and the s55 engine doc. Then re read the m2's engine doc about where it compares its engine with the s55 engine. The only 2 differences between the 2 is one has 1 twin scroll turbo and 1 has 2 turbos. The second is one is air to air intercooled(m2) to air to water intercooled(m4). Meaning the ENGINE is actually a REAL M engine.

Remember from the base n55 75% is similar to the s55. That now changes to the 90% range and the only 10% that doesnt match up is the 2 differences list above. All other components from the s55 were added to the m2's n55. I asked a current BMW master tech these questions and pretty much agreed with me

[mcnevin]

Forgot to add this to my last post.

Ive got a 2017 MG Manual M2 Current mods are Injec Intake, AFE intake duct, VRSF charge pipes, VRSF Catless, UUC short shifter, Pure 3' turbo inlet, JB+(waiting on final non beta maps for bootmod3 before deciding flash tune), VRSF 7' Intercooler, MPE

To be honest couldnt really giving a flying F$%K on whether its open or closed deck design. To busy having way to much fun, its my DD and every time I go driving somewhere, is an experience

[zenmaster]

Yes, the S55 is really a closed deck engine. There are pictures of it.

[DivideBYZero]

Originally Posted by zenmaster

Yes, the S55 is really a closed deck engine. There are pictures of it.

[Nine Lives]

Originally Posted by mcnevin

Remember from the base n55 75% is similar to the s55. That now changes to the 90% range and the only 10% that doesnt match up is the 2 differences list above. All other components from the s55 were added to the m2's n55. I asked a current BMW master tech these questions and pretty much agreed with me

Wishful thinking that the only differentiation between the N55 (in the M2) and the S55 is the turbo and intercooler.

There are major differences between them one of which has been posted as being the closed deck block,different materials,lightened crank,strengthened pistons etc,etc.

[PrematureApex]

Yeah, it's an entirely different block, easily seen from even an inspection from the exterior, heads on.

[Bluenose-2er]

Originally Posted by Nine Lives

Wishful thinking that the only differentiation between the N55 (in the M2) and the S55 is the turbo and intercooler.

There are major differences between them one of which has been posted as being the closed deck block,different materials,lightened crank,strengthened pistons etc,etc.

I am pretty sure that the N55B30T0 shares a number of S55 parts, so you are oversimplifying. But I agree it is definitely not the same block.

Always got to fact check someone who calls the M2 "vanilla"

[Artemis]

Originally Posted by mcnevin

read the m2's engine tech doc and the s55 engine doc. Then re read the m2's engine doc about where it compares its engine with the s55 engine. The only 2 differences between the 2 is one has 1 twin scroll turbo and 1 has 2 turbos. The second is one is air to air intercooled(m2) to air to water intercooled(m4). Meaning the ENGINE is actually a REAL M engine.
Remember from the base n55 75% is similar to the s55. That now changes to the 90% range and the only 10% that doesnt match up is the 2 differences list above. All other components from the s55 were added to the m2's n55. I asked a current BMW master tech these questions and pretty much agreed with me

What the papers said:

• The crankshaft main bearing shells were adopted from the S55 engine. Adaptations were necessary in order to satisfy the higher requirements. The crankshaft bearings are lead-free. A three-material S703C electroplated bearing is used as a material combination for the lower bearing shells. For the upper bearing shells a two-material bearing made from aluminium R25 is used. The axial bearing is effected at the fourth bearing position.
• The pistons were adopted from the S55 engine. Adaptations were necessary on the first piston ring, the plain rectangular compression ring. This had to be adapted as regards the material pairing to a liner made of grey cast iron. This is in contrast to the S55 engine, where this is LDS-coated.
• The oil sump of the N55B30T0 engine is a common part from the S55 engine and is made of aluminium. Production of the oil sump from magnesium for the S55 engine resulted in a weight saving of approx. 1000 g / 2.2 lbs as compared with the aluminium oil sump for the N55 engine. During ongoing production, the magnesium oil sump was also changed to an aluminium oil sump for the S55 engine. An additional oil sump cover in the oil sump also restricts the oil movements during longitudinal and lateral acceleration.
• In the area of the engine electrical system, a different spark plug is used in comparison with the N55B30O0 engine. The spark plug of the N55B30T0 engine is from the S55 engine. The ignition wiring harness was also adopted from the S55 engine. All other components in the area of the engine electrical system of the N55B30T0 engine correspond to those of the N55B30O0 engine.

[Nine Lives]

Originally Posted by Nine Lives

Wishful thinking that the only differentiation between the N55 (in the M2) and the S55 is the turbo and intercooler.

There are major differences between them one of which has been posted as being the closed deck block,different materials,lightened crank,strengthened pistons etc,etc.

Originally Posted by Bluenose-2er

I am pretty sure that the N55B30T0 shares a number of S55 parts, so you are oversimplifying. But I agree it is definitely not the same block.

Always got to fact check someone who calls the M2 "vanilla"

There's no dispute that the N55 in the M2 shares parts with the S55 but I'd wager the difference is more than 10% between them not including the block.

For its application it's still a decent engine but just not as "chocolate" as the S55

[RPM2-85]

All I know is that when I nail the gas in my buddies M3 it sounds like bucket of bolts with loud turbo whine craziness. The distortion comes right through the gas pedal.

With my M2, the things winds out, and is buttery smooth to redline with only the slightest hint of turbo whine. For me its no question, circle jerking the S55 aside, this engine has me smittin. Really feels like a NA V8 or something with loads of torque. My cars tuned, and thats made a large difference as well in the umph department. Whatever, Ive driven both extensively, trying to be completely objective here.

[Artemis]

Originally Posted by RPM2-85

All I know is that when I nail the gas in my buddies M3 it sounds like bucket of bolts with loud turbo whine craziness. The distortion comes right through the gas pedal.
With my M2, the things winds out, and is buttery smooth to redline with only the slightest hint of turbo whine. For me its no question, circle jerking the S55 aside, this engine has me smittin. Really feels like a NA V8 or something with loads of torque. My cars tuned, and thats made a large difference as well in the umph department. Whatever, Ive driven both extensively, trying to be completely objective here.

All a matter of personal taste and interpretation.

[RPM2-85]

Originally Posted by Artemis

All a matter of personal taste and interpretation.

Attachment 1577400

Exactly! Ive lusted for HP high up in the rev range my whole life, but what I didnt know is that I LOVEEEEE low end torque. For street duty, no better. I find this engine to have heaps of low end with a linear pull to redline at 7k. Hardly notice the turbo so for me its perfect. The S55 is highly turbod in comparison in my view. Theres no hiding it with that car and thats why I love this twin scroll single turbo thingy in the M2. It hides it well.