corsaZ22se said:
early x20xev's didn't have balancer shafts but the later ones did and a fancy inlet manifold to get the same power through the rev range as the early engines.
x20xer also didn't have the balancer's which helped them rev out and gain more bhp.
I will ask if they still have the graph from last time, if not I will go for another run.
I know this is an old post but it just irritated me enough to respond.
The fancy inlet as you describe it was fitted before the balancer shafts to provide different length inlet tracts to improve the mid range torque. Which it did. No power increase was achieved.
This new inlet had nothing to do with increasing power due to the balancer shafts that came much later and also depended on the car the engine was installed into. For example the omega got them but the mk3 astra or calibra didn't!