Quote:
Originally Posted by S'Pimp  can also be 
maybe two-piece; only upper part in Mg - lower in Al
cause its no plastic, till the pipes and small things |
Sorry I am a bit confused, which part of the engine are you referring to.
Btw, direct injection SI engines have better thermo efficiency and that means the combustion can occur at higher temperatures, which means the exhaust gas will be even hotter than usual. Notice the exhaust manifolds are thick looking cast alloy (not sure which type) items which seems to me can insulate the heat from the exhaust gas.