[E4ODnut]

There's no reason why you can't get the best of both worlds from a boosted engine. It just takes more time tuning and you have to be especially careful when tuning under boost, that's all.

Some people advocate tuning with EGT. I'm not so sure about it. I do know that EGTs can be very handy if there is lots of documentation on what's acceptable and what's not, like on an aircraft engine. However, when you're experimenting on your own, there is none of this information to base your readings on. The temperatures can vary quite a bit from engine to engine, and just where the probe is placed. Having said that, any information is good information because you can document the temperatures under different conditions to compare it to other conditions.

For tuning power under boost I suspect it would be safer to reference exhaust gas oxygen. Start with a rich mixture and work from there because things are more predicable and the sensor response is very fast. This is just an opinion. I have no experience with boosted engines.

Tuning for economy is much safer because if you screw up you aren't likely to hurt anything. It just takes lots of driving under lots of conditions, data logging, and making small changes at a time.

Probably the ideal situation would be to do dyno tuning first, then do the final stuff on the road under real world conditions. I don't have access to a dyno, so it's not an option for me.