I don't think anyone has ever had this theory before but it makes sense to me especially with the VW emissions scandal. If there's another thread on this I apologize.
I thought a few years back when the f10 m5 came out that the dyno numbers were very inconsistent. No one seemed to be able to get a solid ballpark figure on how much power the car was actually putting down. There was always a 50whp discrepancy lol.
I thought that perhaps the Bosch douche bags along with their uncrackable ECU's also programmed an algorithm that would know when the car was on a dyno. It only seems logical and now a lot more likely that it may be true. I'm not sure if it's through the vehicles built in GPS to show that it's not really moving, or maybe the amount of air being sucked in is a lot less than it would be while in motion, or something along those lines.
The numbers seem a lot more rational with the piggyback tunes because the ECU's are being fed false information which would have an effect on that algorithm. I'm speaking as a layman so maybe someone with more knowledge on the subject could shed some light on this theory
It would also throw the competition for a loop when they try to build something with similar power.