Where else are you going to tune for max power? On the road? Oh wait, you have no way to view or datalog horsepower and torque readings.
I have found that it's best to get the a/f correct on the dyno and get the timing close but safe. For cars needing every last ounce of hp I then make some track pulls and sneek up on the timing one degree at a time checking plugs after each change for signs of detonation. You can do this at the race track or on a " closed street " to find where the motor is most happy. If you have a consistant car at the track you can tell by the mph if your making a positive change. I have seen some cars that are load affected like turbo cars change boost between the load dyno and the street, mine included. Not so much a supercharger thing but definatly a turbo thing. There is a guy at pir who runs a turbo mini van. When he tuned on the dyno no knock on the knock sensor. When he went to the track the knock sensor went nuts. Also some vehicles like ford trucks have a weird pcm that is very load dependant. After tuning one such truck to perfection on a load dyno it ran like crap on the street. Load is a good thing but nothing beats real world driving conditions. Now that being said most people do not have the patience to tune that way and not all vehicles need to be tuned that way. Obviously for a hci car or stock motor with a
vortech that would be overkill. But for anything with a power adder making over 450hp it sure never hurts to pull some plugs. If you get a good tuner who has tuned quite a few cars then they will know what the limits of each engine are and what is safe for the street. I was probably out of line saying that anyone tuning for max power on the dyno is an idiot. It would have been more PC to say that they are asking for trouble. Sorry if I offended anyone.