Join Date: Oct 2004
Location: Aberdeen Scotland
2.5" and 3" headers? Those are incredibly wide exhaust ports. Holy hell! I don't even know how they fit that in the engine bay...
All jokes aside, If we're talking about collectors I would assume it has to do with the fact that a 2zz has to push 400bhp worth of exhaust through a single 3" collector from a single header while a 2GR has 2 collectors from 2 different headers off of 3 cylinders only contributing half the total horsepower. 2.5" piping was probably shown to provide adequate flow for the required exhaust volume while maintaining velocity for scavenging.
Performance exhausts for 2zz-ge Elise & Exige at