What I think what he wants to do is change the max speed of the car to like 50 KMH. I haven't dug into the game files all that much. (I'm kinda a video game Puritan. I don't mod things unless I think I really have to.) But to change the way the engine of the car works might take a bit of software engineering. Even for custom cars. Sorry about the delay in response to your question in "General". I have been pulling heavy overtime.
All right. Back to your question. Now you said in your post in "General" that you downloaded a modder car. I need these questions answered.
1. Are any of the files written in Russian?
If so, I cannot help you as I cannot read Russian, and in software engineering, translation is too inaccurate to even attempt.
2. Did the car come as a bunch of files, or was it packaged as an executable (.exe)?
3. See if you can't give me the names of what you thing might be configuration files.
These types of files might be XML, .csv, .ini; if you can open it with a text editor or Excell, chances are it's a config file.
Going through the config files mysesf I found some under physics\engine labeled losts and power, as well as Clutch Losts and Power .csv files that all had RPM labeling in them, but decoding them looks about as fun as pulling teeth. I suppose if this is REALLY that important to you, I can mess around and see what I can do. I also found some under transmission, but they look like they are for automatic transmission only.
@Colaplus95: I keep trying to tell him that cars don't shift until they hit 25 MPH (40.234 KMH), but he refuses to listen to me no matter what I tell him. Oh well, I suppose we can try to fix the game so at least he's happy in his augmented reality, but like I said; looking at the config files, this ain't going to be easy. I'll see what I can do.