I know engines and fuel systems IRL, but I’m interested on your findings about an '80s engine.
IRL, a 2-litre DOHC four would be able to produce about as much power with 2x2-barrell carbs as with a mechanical fuel injection, like a K-Jetronic for example.
But the FI engine would be more economical and run smoother than the carb engine. What effects these two options have currently in-game? I haven’t had time
yet to do comprehensive testing so I’d like to hear from your experience.
It wouldn’t be so much smoothness as it is responsiveness… carbs require a lot richer fuel mixture than injection, and responsiveness suffers. The smoothness here is largely determined by the bore, stroke, cam profile, and which material is used for top end parts.
Fuel injection allows more accurate Air/fuel ratio under varying drive conditions, hence the added smoothness; however, a twin-carb -engine would generally be more responsive than a K-Jetronic-system - the shorter intake system with less moving parts contributes to this. If you drive an older car that has both fuel feed options, such as a Saab 900 or a BMW 2002, the difference in responsiveness is immediately noticeable - the carb engine has little or no delay in reaction when the accelerator is pressed, where the mechanical fuel injection system will have a slight delay.