Hi guys, need to ask you guys a question.

How do people tune their cars without dyno machines?

are dyno machines absolutely a matter of life and death for a turbo engine?

is this a viable choice, equiped with a high tech O2 sensor, you first tune it extensively on the road (haltech/microtech/whatever), then you turn to the dyno to fine tune it.

as a way to save dyno time cost. thanks