Quote:
Originally Posted by stressdoc
Here are my thoughts: 1) We won't get the failure analysis results on this case. That information is proprietary. 2) The pattern of (very rare) N54 engine failures indicates a weakness in cylinders 5&6. This appears to be heat-related. 3) BMW engineers their engines to withstand a wide range of conditions, including the rigors of sustained high speed loads during autobahn travel.
The OEM engine parameters, including boost levels, are decided on the basis of performance/reliability/cost algorithms. The stock 335 is a phenomenal car, providing extraordinary acceleration, handling, and braking for a relatively low cost. Aftermarket engine tunes alter the balance. In the case of the N54, dramatically so. Power increases of >60 hp for under $1k. We now have the potential for supercar performance at a bargain basement price. However there is an inevitable trade-off in reliability. In normal dd conditions in the USA/Canada, and other countries with low speed limits, the reliability consequences are likely small. In racing conditions and high speed driving on the autobahns, reliability would suffer more, in particular because of the difficulty in providing even cooling to cyl 5&6.
Look at what BMW engineered in the 335is and the engine performance kit. The focus is on cooling -- higher output fan, changes to software for H2O pump, ducts, additional radiator, ...
|
seems certainly cyl 6 goes hotter but in my case it was cylinder/piston 2 that failed. All other pistons were pristine.
I am running now the exact same injectors as before. (changed HPFP though)