While working on new stuff, and updating old mods and always got feeling that something is wrong with how cars reacts on throttle pedal.
Recently Niels Heusinkveld made bunch if useful videos on this topic with explanations. Kudos, Niels!
TLDR: most of games/sims implementation of the throttlePedal-to-engine reaction not really matches how it works in real life. Including AC, ACC, and AC Evo.
It is about how game translates our throttle pedal position into engines torque.
Main idea is that dependency which is expected to be like this in road cars:

instead implemented like this in AC, ACC, and AC Evo:

I've implemented improved version and soon we'll get an updated cars with a next small step of simulation level.
See you soon!