Originally Posted by Johnny D
Put that e46 in a container and ship it here. I'll dyno it, and guarantee it wont match your numbers. That is what he was saying, not wheel spin... Which has zero to do with this convo.
My point was that a good dyno insures that you have an accurate hp reading, rather than a margin to compare your runs to. I agree that it is always better to compare your runs on the same dyno, but a good ECU map is a good map, period. Also, the reason why I mentioned wheelspin is simply because when wheelspin is present, the margin of reading error varies from run to run. So you can't accurately monitor the changes your car is making.