Im not professing to be an expert (far from it) and both Nick & Dave you will know a lot more than me. So im after a bit of education.
However,
Downforce & Aerodynamic lift are apparently not important. So your telling me that a car travelling at say 120 mph, on a track, that the effect of the weight being put on the car by the wind has no bearing on what the engine is doing. Despite the fact it will be having to work harder to keep the car at that speed to push through the wind resistance?
I understand that a RR is a fantastic tool when used properly, by a competent tuner, and that you can do things on a RR you can't do on Tarmac in the UK (unless you have your own track) like the situations you have previously mentioned.
But if a Dyno was THE best way then how come all the professional motorsport teams & tuners like REVO & APR do real world testing (i know it's not just to do with the engine for motorsport)? Surely they would just stick their vehicle on a Dyno with a big feck off fan in front of it, set it up perfect and then give it the driver??
As i said im not professing to be an expert and i am just curious