[atek]

I'm interested in seeing what it would take to get to 600whp with the M235i N55. Is it possible? Has it been done? From my research, nearing 500whp seems very doable even before Turbo upgrade. Theoretically, it would just need the right sized turbo and of course supporting mods.

My question comes down to, do we know if the internals will hold up? And if so, how long? Street/Highway use, no track.

Maybe there's a thread on here I haven't seen yet... I am aware the transmission of the zf8 is going to be nearing its limit around that torque generated. I've also seen M340 zf8 is a worthy upgrade in that case.

What else would be needed, if any?

[XutvJet]

Certainly possible and as been done in M235/M2/335 community over the years with EWG N55s. Your M235s N55 already has a forged crank, S55 forged rods, S55 rod and main bearings. Just keep in mind that all reliability goes out the window and one major split second hiccup can take out the motor.

I would not expect an N55 to live very long (12k miles,, year maybe) behind 600whp and while it's alive, you'll be spending lots of time fixing constant tuning and driveability issues.

The S55 M cars are a far better starting point for big power numbers. Even then, they can have issues holding together at 600whp.

Mods at minimum to hit 600whp with an EWG N55:

Big, laggy turbo
B58 HPFP
Ethanol mix
Upgraded low pressure fuel pump
Big intercooler
Lots of tuning
Prayer

[atek]

Originally Posted by XutvJet

Certainly possible and as been done in M235/M2/335 community over the years with EWG N55s. Your M235s N55 already has a forged crank, S55 forged rods, S55 rod and main bearings. Just keep in mind that all reliability goes out the window and one major split second hiccup can take out the motor.

I would not expect an N55 to live very long (12k miles,, year maybe) behind 600whp and while it's alive, you'll be spending lots of time fixing constant tuning and driveability issues.

The S55 M cars are a far better starting point for big power numbers. Even then, they can have issues holding together at 600whp.

Mods at minimum to hit 600whp with an EWG N55:

Big, laggy turbo
B58 HPFP
Ethanol mix
Upgraded low pressure fuel pump
Big intercooler
Lots of tuning
Prayer

If the internals are so good, why would it only last 12k miles? Can you elaborate on what makes it so difficult to tune reliably at that level? I'd understand constant (10k mile or less spark plug changes. Wouldn't think much else necessary...)

For such a great motor that responds well to little mods, I'm surprised the upper limit is so low. Thanks for the insight and info though. 500whp may be enough for the feeling I'm after in the chassis, won't know until I crack that mark.

[mike@x-ph.com]

You need to upgrade your turbo for that kind of power to keep it reliable.

Its certainly doable and safe in my opinion

[aerobod]

Originally Posted by atek

If the internals are so good, why would it only last 12k miles? Can you elaborate on what makes it so difficult to tune reliably at that level? I'd understand constant (10k mile or less spark plug changes. Wouldn't think much else necessary...)

For such a great motor that responds well to little mods, I'm surprised the upper limit is so low. Thanks for the insight and info though. 500whp may be enough for the feeling I'm after in the chassis, won't know until I crack that mark.

If you don't use the full power output that often it will certainly have a much longer life between rebuilds. If it is used regularly on the drag strip (say weekly in the summer) or used weekly on the track where the revs are always kept in the upper 1/3rd of the rev range and at full throttle, then 20,000km / 12,000miles is a reasonable rebuild interval for an engine making over 200bhp per litre at the crank when the original design output was around 120bhp per litre.

[atek]

Originally Posted by mike@x-ph.com

You need to upgrade your turbo for that kind of power to keep it reliable.

Its certainly doable and safe in my opinion

Yes, this was my understanding as well. Jordan from RK tunes believes heavily in the N55 at that power level.

Originally Posted by aerobod

If you don't use the full power output that often it will certainly have a much longer life between rebuilds. If it is used regularly on the drag strip (say weekly in the summer) or used weekly on the track where the revs are always kept in the upper 1/3rd of the rev range and at full throttle, then 20,000km / 12,000miles is a reasonable rebuild interval for an engine making over 200bhp per litre at the crank when the original design output was around 120bhp per litre.

Yea, its a street car. My daily to work plus occasional highway pulls with friends and strangers, thats all. No track and probably only drag 1 or 2 times to get a the #s.

[XutvJet]

Originally Posted by atek

If the internals are so good, why would it only last 12k miles? Can you elaborate on what makes it so difficult to tune reliably at that level? I'd understand constant (10k mile or less spark plug changes. Wouldn't think much else necessary...)

For such a great motor that responds well to little mods, I'm surprised the upper limit is so low. Thanks for the insight and info though. 500whp may be enough for the feeling I'm after in the chassis, won't know until I crack that mark.

Keep in that BMW specifically noted that it felt that stock "365hp" in 2016-2019 M2 (EWG N55) was as far as they felt they could push that motor for a factory warrantied car. The N55 in the M2 was making 330whp/360wtq stock or around 390hp/420tq. Some of BMW's concerns were related to intercooling which the M2 runs the same IC as every over N55.

As aerobod noted, in stock form, the EWG N55 makes between 100-120hp/liter. That's somewhat high for a factory production motor. A stock S55 M2/3/4 is making around 155-165hp/ltr which is quite high for a production motor plus that motor has a closed deck block vs the open deck block of the N55.

An N55 pushing 600whp is making around 710hp. That's a whopping 237hp/ltr. There's not a production motor in existence pushing that level of hp/ltr. I believe Ferrari is the nearest with 219hp/ltr in the Ferrari 296 GTB.

The N55 is garden variety motor and not some race bred exotic motor. The N55 is a strong motor, but to think that it should reliably handle twice it's designed power levels is a bit crazy. Also, the block might be able to handle the power for a while, but there are plenty of other things that won't be up to the task over the long term, specifically the head gasket, crank hub (spun), cooling system, and transmission. The 8AT will live for a little while, but it will give up after a while. If it's an xdrive, expect to replacement transfer cases fairly often. Same goes for the 6MT. You won't be able to rip the gears for fear of shearing a gear, input shaft, or axle. You'll also need a stronger clutch.

Like said, 600whp in the N55 has been for a while now. But you will be walking on egg shells with a car requiring constant tuning babysitting, repairs, leaking seals/gaskets (because of all the internal pressure, high heat, etc.) and one that will be one major knock event away from a cracked or melted piston or ringland, a bent or broken rod, or spun rod bearing(s). With that level of power, the N55 is operating way outside of what the OEM safeguards can deal with.

[MadJonny]

Hello Atek,
My current build is looking at that power level.
Look also at NV Motorsport UK he has got 625 on a OG M2