xfi motor? It has a new design engine from IAV in it. What's a xfi?
The xfi is the best MPG model Metro. The engines are the same except a few minor changes. There is only 1 compression ring. Not the usual 2. I really don't think this did much for MPGs. The big difference is the the Camshaft on that engine has sharper lobes which changed the torque curve. It moved it lower which is way better for a gutless engine.
Another difference is there is a slightly different tune on the ecu. From what I noticed it didn't make much of a difference.
The last main difference was the gear ratio in the transmission. The final drive in the xfi was 3.79 vs 4.10 or 4.39 in the 3 cylinders. The Cam and transmission were the main improvements.