Originally Posted by Diver
1M has an N54, 135is has an N55 with PPK II.
The layout of the intake and the rear pipe into the intercooler continues to convince me there is a second blower and it is not an exhaust driven turbo, but rather an electric supercharger. It appears that the second unit is located too far down and back to be exhaust driven, given the layout of either the N54 or N55 exhaust driven turbochargers.
Thanks for the info. Does the 335iS and Z4iS share the same N54, or does the 1M have changes?