There are many "Tuners" that show a result in full throttle HP but go totally the wrong way about it. I'm often surprised by the poor quality of the tunes that come through our door, make the numbers but have fuel trims that are way off, have incorrect commander AFR's that don't match the actual AFR's and rough hacked VE tables, the VE table is the backbone of any tune as the ecu calculates load and torque from it so it needs to be right, and not just at WOT. If the engine has only a few modifications its true that a tweak of the timing and a change in commanded AFR may be all that is needed, mostly I find if an OTR is fitted then some MAF scaling is required and the VE table should be first made right with the MAF disabled, something I know most tuners do not do. Also many people rely on the knock sensors to do the work putting in more timing than they should and the result is less power and less smooth power delivery. To do the tune correctly requires knowledge of how the ecu works and what to log/adjust so the parameters are all correct and the drive ability, starting and economy are all great, not just WOT.
