[goodNIGHT]

I have a 2015 M235i and returning from a 2day track day event north of Dallas a few weeks ago and I heard a clunk and the engine shut down. I found out that the fuel pressure control module and fuel pump broke.

After 108k miles I am now nervous about doing any more track days with it. Not sure if Im overreacting but Im starting to look at other track/weekend cars, namely the OG M2, the A91 supra, and the GR86. Maybe even the Zenos E10.

How is the N55B engine in the M2 in regards to reliability? They seem to be doing well out there. The B58 also seems better than the N55 but I have heard the B58 has fuel pick up/starvation issues in high g corners - so it also makes me nervous how 'track reliable' that engine is over time.

I have thought about the Mach1, mx5s, the Z, used caymans, but the ones i listed have the most appeal to me.

Any insight on which engine (n55B/b58) provides more robustness out there would be appreciated.

[Vojta89]

Originally Posted by goodNIGHT

I have a 2015 M235i and returning from a 2day track day event north of Dallas a few weeks ago and I heard a clunk and the engine shut down. I found out that the fuel pressure control module and fuel pump broke.

After 108k miles I am now nervous about doing any more track days with it. Not sure if Im overreacting but Im starting to look at other track/weekend cars, namely the OG M2, the A91 supra, and the GR86. Maybe even the Zenos E10.

How is the N55B engine in the M2 in regards to reliability? They seem to be doing well out there. The B58 also seems better than the N55 but I have heard the B58 has fuel pick up/starvation issues in high g corners - so it also makes me nervous how 'track reliable' that engine is over time.

I have thought about the Mach1, mx5s, the Z, used caymans, but the ones i listed have the most appeal to me.

Any insight on which engine (n55B/b58) provides more robustness out there would be appreciated.

From the list you wrote there I would take A91 Supra. But I would think about Supra or M2 Comp with S55 and would pick up M2C

Fuel pick up/starvation issues in high g corners is not issue with the engine but with the tank. It has every street BMW as far as I remember from E46. Probably similar issue with most of street cars, when the level of fuel is low enough (mostly under 1/4 of tank) and you take long right turn, it sucks air…

S55 and B58 are hoth closed deck architecture, that make them very robust
N55 you have in M235 or is in og M2 is open deck

[3LiterBeater]

Not to rehash those silly old open vs closed deck arguments, but it's really not a concern in modern day cars. Casting technology is leaps and bounds above what it once was.

I'd be willing to bet the N55B is stronger as the iron cylinder walls will be more rigid than aluminum while possessing much better wear properties. There has been more than one case of a heavily tracked S55 cracking a cylinder wall. Among other things, it's also much lighter than the S55.

To answer OP, fuel starvation is real. Just keep the tank above 1/2 before you go out on track. This exact engine was used in the M235R (and M240R) race cars. The teams I spoke with stated they had zero reliability issues, even in endurance race settings.

[///393]

Originally Posted by 3LiterBeater

This exact engine was used in the M235R (and M240R) race cars. The teams I spoke with stated they had zero reliability issues, even in endurance race settings.

::flex::

[3LiterBeater]

Originally Posted by wilson kop

::flex::

To be fair, the S55 has been used even more so in the M4 GT4 and M2CS Racing.

I try to calm the arguments stating the N55B is any less of a track-capable engine, as it is not.

[kthor703]

The n55 motor in everything but the M2 does have concerns of oil starvation. It doesn't have the extra suction pump for the oil pickup that the OG M2 and M2C has. You can fit the sump and pump kit though,, as the m235iR and 240iR do.

Was one of the reasons I jumped from my m235i to my M2C.

[3LiterBeater]

Originally Posted by kthor703

The n55 motor in everything but the M2 does have concerns of oil starvation. It doesn't have the extra suction pump for the oil pickup that the OG M2 and M2C has. You can fit the sump and pump kit though,, as the m235iR and 240iR do.

Was one of the reasons I jumped from my m235i to my M2C.

Correct, though I hear the sump in the racing cars are slightly higher pressure. Something like allowing up to 1.8 G, or something like that

[goodNIGHT]

A lot of good points.
It seems like with S55 oil pan, lines, pumps the N55 would be a relatively reliable with track use. But m235i just lacks too many track ready components so….

If one were to buy one last ICE car for fun- I feel like the S55/B58 are the best choices. I think the M2 is still my sentimental favorite(the sounds *drool*) but in reality the M2c and Supra are probably the best future proof options.

This is a good article
https://bmwtuning.co/n54-n55-b58-s55/