Situation with N53 series engine (x23i/x25i/x30i) is pretty simple:
- first bank – cylinders 1/2/3;
- second bank – cylinders 4/5/6.
For N43 series engine (x20i), make attention to the exhaust manifold:
As we see, for N43 series engine (x20i):
- first bank – cylinders 1 and 4;
- second bank – cylinders 2 and 3.
For N43 (x16i/x18i): first bank – all cylinders