[O Haiii]

Why is it that the N55 struggles to retain power at the upper rpm ranges? Unlike the B58 which keeps going strong all the way to redline, our N55 loses substantial power and torque as we approach redline. Is there any mods that can help remedy this? Thanks in advance.

[medphysdave]

I'm sure it has been discussed at length somewhere, but I'll throw in my two sense. Usually the loss in top end grunt it from a lack or air or fuel. I suspect that the turbo is the limiting factor. Likely a smaller turbo to minimize lag, but trade-off is top end pull.

[gmzanatta]

Originally Posted by O Haiii

Why is it that the N55 struggles to retain power at the upper rpm ranges? Unlike the B58 which keeps going strong all the way to redline, our N55 loses substantial power and torque as we approach redline. Is there any mods that can help remedy this? Thanks in advance.

Bigger turbo. Small turbo on N55 makes it short of breath at top range.

[CommitConfirm]

Heat. You can see the ECU pulling timing on the top end.

Fitting a FMIC allows the ECU to maintain timing for longer.

[PackPride85]

Originally Posted by gmzanatta

Bigger turbo. Small turbo on N55 makes it short of breath at top range.

This is the main cause.

[XutvJet]

I wouldn't say the N55 in the M2 is loosing a substantial amount of power in the upper rpms. Looking at numerous dynos, power peaks at around 6200rpms and holds until 6500rpms then falls over the 500rpms. Those last 500rpms aren't that significant. The calculated ideal shifts points for a stock 6mt are red line on the 1-2 and 2-3 and 6700rpms on the 3-4.

[look585]

The engine is perfect.

[Bluenose-2er]

Originally Posted by hogger453

The engine is perfect.

Well, maybe not perfect but pretty darned nice!

Other than the 'newer is always better' perspective, I have yet to see definitive evidence that the B58 is a significant improvement in the power ranges we are talking about. Bigger turbo means more tuning room - but also more lag. Closed deck means more cooling challenges. Modular construction means losing access to shared S55 parts.

[RPM2-85]

stage 2 hex, fmic, fabspeed HFC. Little rocket. How it should have been. Need M4 size rubber next. The smaller turbo keep the spool times real short, feels much more linear like a NA. The S55 is a beast at 7k rpm, but laggy in comparison down low. For street trim the N55 its pretty ideal and my setup really negates and criticism I could have had before. Pulls alll the way

Stock it was good, but a proper flash and some mods gets the best out of it, an epic epic M car.

I have 25k miles now.....

[stefan]

Originally Posted by hogger453

The engine is perfect.

Someone drank the koolaid. There is plenty of room for improvement with the N55. Namely total cooling and turbo size.

Though you can see why the N55 was used. Much less laggy than the S55. We can excuse the S55 of this downside as M cars have always been a bit sluggish in the low RPMs except maybe the E39 M5. The M2 is a different beast.

Personally I do think the B58 is all round a better unit.

[kiysersosae]

It's a combination of the frontal area and twin scroll turbo running out of puff! The heat issue is not that bad on the road, the car won't pull timing until 50deg c and above. Maybe in some hot countries cooling will be more of an issue but it would be simmilar for most cars.

If you can't get the air in you ain't going to get the power out!

[No Boost]

N55 is very capable. It just needs some massaging.

[O Haiii]

For a quick comparison. B58 Torque doesnt drop off til late and power pulls strong til redline. I know we didnt buy our cars for straight line speed but you can make the same argument about the M240i. It's a more superior engine. Either way rant over. I love this car.

[True Story]

Why does the M240i recieve the B58 and we only have the N55?

[johnnydad]

I did a BMW M driver training day again last week, and we were driving M4s all day. To be honest, I didn't find there was a huge difference between the top ends of these and my stock M2. The M4 felt a bit faster, but that was strength across the range rather than it being significantly freer-breathing over the last 1500rpm - nothing like a VTEC honda or even the old V8 in the E9x.

Maybe our 98 Octane helps a bit?

[jayg80]

Originally Posted by RPM2-85

stage 2 hex, fmic, fabspeed HFC. Little rocket. How it should have been. Need M4 size rubber next. The smaller turbo keep the spool times real short, feels much more linear like a NA. The S55 is a beast at 7k rpm, but laggy in comparison down low. For street trim the N55 its pretty ideal and my setup really negates and criticism I could have had before. Pulls alll the way

Stock it was good, but a proper flash and some mods gets the best out of it, an epic epic M car.

I have 25k miles now.....

Is the fmic required for the stage 2 with hfc? Assuming no track use?

[O Haiii]

im curious as to how the car dynos with aftermarket fmic and no other mods.

[Bluenose-2er]

Originally Posted by True Story

Why does the M240i recieve the B58 and we only have the N55?

[SeanWRT]

What a load of crap...Basically everybody created its own way of bragging about its car here above.

Speaking from experience in extensively testing on N54/55&S55 and a few B58s. Be realistic guys, compared to its competitions, N55 shines only on exhaust notes and reliability. NOTHING else as of yet.

Top end...please wake up guys!

[johnnydad]

Originally Posted by SeanWRT

What a load of crap...Basically everybody created its own way of bragging about its car here above.

Speaking from experience in extensively testing on N54/55&S55 and a few B58s. Be realistic guys, compared to its competitions, N55 shines only on exhaust notes and reliability. NOTHING else as of yet.

Top end...please wake up guys!

Pretty hard to argue with that.....

Maybe if it made sense it would be easier.

[kab_m2]

Originally Posted by SeanWRT

What a load of crap...Basically everybody created its own way of bragging about its car here above.

Speaking from experience in extensively testing on N54/55&S55 and a few B58s. Be realistic guys, compared to its competitions, N55 shines only on exhaust notes and reliability. NOTHING else as of yet.

Top end...please wake up guys!

[AESZ4]

Originally Posted by johnnydad

Pretty hard to argue with that.....

Maybe if it made sense it would be easier.

lol