[moldcad]

Is it 100% known what are the exact differences between the M235i and - say- 435i flavors of the N55 engine? Is the 235 additional power and torque from tune only, or is the tune assisted by some significant hardware differences?

Asking because I'm cross-shopping for the 435xi, and I wonder whether it's possible that the M235i specs make it to the 435i in the MY 2015 (i.e. starting July 2014)...

[jrstech]

Originally Posted by moldcad

Is it 100% known what are the exact differences between the M235i and - say- 435i flavors of the N55 engine? Is the 235 additional power and torque from tune only, or is the tune assisted by some significant hardware differences?

Asking because I'm cross-shopping for the 435xi, and I wonder whether it's possible that the M235i specs make it to the 435i in the MY 2015 (i.e. starting July 2014)...

I can't confirm this but I read somewhere that this N55 uses a different (steel) crank shaft than other N55's.

[jrstech]

Just checked on ETK and the M235 & 435i have different crank part #s.

[bladeomatic]

Agreed. I believe the M235i has a forged steel crank vs cast iron.

[M.barnes]

55hp engine has forged crank yes

[ska///235i]

Also Mike confirm the DP is 4" and the 335/135 has 3.5" DP (downpipe)...up till 7/13

[GTM_Challenge]

Originally Posted by ska325xi

Also Mike confirm the DP is 4" and the 335/135 has 3.5" DP (downpipe)...up till 7/13

Correct, all F series cars up to 7/13 have one downpipe design, after then all F series cars have a newer design as does the M235i.

We are finishing up production on our revised design here in the next few weeks.

[moldcad]

Thanks guys; fast-forward a few months and I'm still cross-shopping between the M235i and the 435i with M-performance power kit. In your answers, I find the info about M235i's forged crankshaft interesting; would it mean that by design, the car has more tuning potential than the 435i? I guess so...

[bladeomatic]

Originally Posted by moldcad

In your answers, I find the info about M235i's forged crankshaft interesting; would it mean that by design, the car has more tuning potential than the 435i?

Certainly.

As the backbone for the entire engine, a forged crank is going to be a significant piece in determining how hard things can be pushed. There are plenty of other areas that need to be beefy in order to soup things up, but a crankshaft is one key piece.

It also makes me wonder if they did this so they could use similar core engine for the M2, which will have much higher output.

[jofealvi]

Here is another link with and interview in the Detroit Auto Show, when confirmed the Steel crankshaft, in the BMW M235I.



http://www.2addicts.com/forums/showthread.php?t=935130

[overcoil]

^^^
Just went out and hugged my 235 after reading that link👍