air is not constant on turbo diesels though? and timing will also affect power/lambda emmissions! its too complicated!
On my 1.9 xutd, i screwed the wastegate as tight as it would go (a diesel unlike a petrol will only make as much boost as the ammount of fuel you put into it) and i screwed up the max fuel screw a substantial ammount, i then fiddled with the diaphram in the boost compensator to try and reduce smoke emmisions off boost. it was really quite nippy after that! 22 psi of boost lol. Common rail stuff, if you had the software would be quite in depth to tune i would think.