Thu Feb 25, 2016 1:08 am by TurboJ
There are certain differences in how turbos work on this game and in modern real-life turbo engines. The turbo tech in the game is based on '80s tech and it will be overhauled in the future to include modern-day systems.
Only very lately real-life cars have begun using such high boost pressures. 10 years ago only special versions of Evos and such had 1.5 bar boost pressures. So as long as the game uses old turbo tech, you need to take that
into account. High pressures like today would cause intolerable heat loads with '80s compressors. In-game you will notice that there are certain limits within which your boost pressure increases have a positive effect to power;
after that certain limit you will run out of the efficiency map so to speak.
In the game, you need to use relatively high compression ratios for road engines, because otherwise you will lose a lot of fuel efficiency and responsiveness. You adjust your power more by turbo sizing and less by turbo pressure.
For optimal results you will use slightly larger compressors with smaller turbines. For very sporty engines you need high A/Rs and lower for eco-engines. Furthermore, with a small turbo you need MORE boost pressure for a given
horsepower amount. Air flow and boost pressure are not linearly connected. The larger the compressor, the lower the required boost pressure for the same amount of air flow.
For direct fuel injection you can use 10:0 compression ratio to begin with; you will then reach 110-120 hp per litre or more with boost pressures of 0.55-0.75 bar. (This is an estimate, I can't login to Automation right now.)
For a supercar engine you can go down to 9:1 CR - any lower than that won't really be good as you will have low efficiency and response. For Non-direct injection ballpark is 8 - 9 CR.
One thing I have noticed is the game doesn't represent non-intercooled turbo engines very well. IRL Lotus Esprit Turbo and Maserati Biturbo had 90+ horsepower per litre in 1981 without intercooling and even used carburettors
for fuel, yet were reasonably economical. In the game you will need very rich mixtures or very low compression ratios if you run without an intercooler.
Other than that the in-game engine designer is GREAT. It's amazing really how close to real world engines you can get. It's only forced-induction little details that need polishing.