HolyCrapItsFast
Drinks beer!
I understand its just a very rough drafted guideline but im curious to see!
Is there a margin for VD vs a real dyno to see how far off the numbers really are?
Nope... to many variables. The road surface, the incline or decline, the head wind etc.
When I do it I find a perfectly level road or a slight decline and I use the same stretch of road all the time and on clam clear days.