[aws]

I have seen a twin turbo 993 being spun 7200 for 75 race hours making 500 HP to the rear wheels with no major problems. This engine had a stock bottom end with only Carrillo rods. Stock pistons and heads, no center main oiling mods, stock oil pump. Porsche narrowed the rods in order to thicken the throws when they redesigned the 993 engine much like they narrowed the 3.0 rods from the 2.7. The problem with this is that there is not enough bearing area to support the forces generated by the longer stroke and higher RPM'S. The 993 crank is torsionally more rigid, but this does not outweigh the reduced bearing area. Part of this opinion was caused by Porsche going back to the 964 based crank with the earlier 3.2-3.3 rods and more rod bearing area when they developed the 4 valve water cooled GT-3 RSR engines. ( that are spinning 9200 in the Daytona Prototypes). I think 7200 with a stock engine with aftermarket rods will work because I have seen it, anything more than that and you will have to talk with someone with a lot more experience with these engines than I have.