Originally Posted by OppositeLock
I believe the only question in the OP is what causes the difference in mod for mod performance?
This is really the best summed up answer imo.
Here's my list of reasons why the 46G3 is better (especially the last version):
1. VE (the rest of the list really all leads up to this)
2. Inline engines can run quite a bit leaner afr's safely (lean=power).
3. 4g63 can run considerably more boost safely due to an iron block and because it has better knock resistance.
4. This is complete guess but I'd imagine the ecu and knock control on the EVO is much more tuner friendly.
5. Mivec on the intake and exhaust cams.
6. Equal length exhaust manifold and twin scroll turbo from the factory, it also has a reasonably sized turbo.
It really doesn't take a genius to figure it out. We're comparing a 2.0l to a 2.5l in factory trim and they make basically the same power. And when one starts adding power to both engines we all know the 2.0l in the EVO gets the edge. As oppositelock said the 4g63 simply has better VE; therefore, it's a better engine.