I'm not an expert on this, but there are many parameters that work together and are interrelated to determine aircraft performance. The "thrust_scalar" setting for engine data is one that does act independently of others and can give you ridiculous amounts of power. Weight, drag scalars, etc will also affect acceleration.

Back up your original cfg file before changing anything. You can also add 2 slashes "//" at the end of a line and put the original settings after them. The double slashes make the file ignore anything after them for each individual line.