Hello i absolutely love this game considering i am a avid backyard mechanic myself, this game has a lot to offer about engine building, if there could be more about the car or suv as well would be even better but im happy with this. The Real issue i have is i tend to spend hours with every objective done except one, and i cant usually find a way to squeeze something else to make it go 5km/h faster or i need 2 readability, i think there should be a suggestion that comes up more often to help your problem, maybe some kind of advice not saying what you have to do but to explain a little more. I bet most people that play this game has no idea what compression ratio their car runs on or what type of engine, i know all this about mine but like i said it needs to have some more advice or better tutorials to more explain where to look for certain things.
there are a lot of new features in the next big update, as you can see here. youtube.com/watch?v=Rf1iPAnPmEE
It will be easier so see, what happens, when you change your settings 