At most all that would be is a general comparison. And truthfully, even a back to back comparison would still be a general comparison. There are just to many variables involved to truly have a definitive fair comparison. IE: Traction, Human Input, Trans loss/shifting irregularity. Maybe it wouldn't be that far off. I don't know.
I do know on any dyno... I could take a truck, with Turbo A and make a number with a controlled climate, humidity, gear ratio, load profile, tuning, etc. Then just after shut down swap turbo B and repeat the same scenario within minutes. For accurate repeatable results, that is the most Scientific way of measuring gains or losses. The only change is whether its Turbo A or Turbo B. But logging metrics is critical as well. Knowing how boost & temperatures are affected with A vs B are just as important.
Take this for an example: If Turbo A makes X horsepower with 1500uS and 20 degrees of timing, while peaking at 1400* EGT and 50 PSI of boost, and turbo B only peaks 1200* EGT and 45 PSI of boost yet still achieves X horsepower what does that tell us? Did we gain? Even if our Horsepower is identical (X) from A to B, its safe to assume we are working much closer to peak potential with turbo A than turbo B with a 1500uS shot and 20 degrees of timing right? In theory, we could then keep adding fuel to turbo B until we hit 1400 degrees and 50 PSI. At that point we would see the gain in horsepower from turbo A to turbo B. That's the sort of data that can not be quickly gathered and digested on a track. But the sort of thing that doesn't matter when it comes to bragging rights!
:rofl:
Caleb