Originally Posted by nicknaz
That's actually not a moot-point..
That info on the engine running hot and multiple heat cycles causing cracks, as well as connecting rod failures should be a key consideration for someone looking for a sporty car to modify and use for track days
Maybe buying the F80 with brand new S55 motor isn't a great idea yet... (but then again, what new motor design is a risk free... great example are the water cooled porsche engines, and most recently the 991 GT3 fire issue)
what does the S55 motor have to do with the N20?
please find and read the original thread on the other forum. The original claim made was that the head cracked after about 100k miles with 331lbft of torque.
as i said before its a moot point right now as there is no aftermarket options available for the N20 that will bring it to these power levels (still don't even have control of the electronic wastegate yet). In addition, I haven't seen or heard of a single instance of an N20 head cracking.
The possible piston issue is cause for some concern if/when larger turbo upgrades start to become available. The stock turbo is good for about 24-25psi of boost, though 23psi seems to be where the engine is making best power with the stock turbo. The N20 is now on its 4th piston revision (one variant with different oil spray nozzles). The original piston was used up to Feb 2012, second until April 2013, third until August 2013 and the current variant. This many changes in that short of a time period says BMW had been working through an issue - especially the second variant only being in production for 2 months.
The N20 in the Z4 is great on the track with the stage2 JB4. I had mine out for about half of last season and will be out about 25 days this season. Like anything else though you have to be prepared for additional maintenance (which you should be doing anyway if you track a car).