I wanna set up some Gr4 races and I wonder which settings to use to get "realistic", competitive races.
Race duration will be ~20-30 minutes and I don't wanna take P1 on lap 3 and do a time trial for the rest of the race.
AI will be set to "professionally" ofc. But I wonder about "BoP" and "Boost". Will the former one alone be enough to make races competitive? Or shall I turn on "Boost" also? I've read a lot about Boost but it seems like it's always just guessing and nobody really knows how it works/what exactly it does.
Don't use BoP if you want the absolute most competitive event. Generally most un-BoP'd Gr.4 cars are in a similar PP range (the modern ones especially) but you can tune them all to the same value if you want.
Un-BoP'd Gr.4 and the ECU (Fully Customisable Computer) percentage at 95/96% for your car only should be pretty competitive.
To do this, leave your/the AI's car at 100% ECU/power limiter percentage. Once you're in the pre-race menu, go into the car settings and change your ECU/power limiter percentage.
If it's a one-make while using the "Select from Garage" option, do not go back into the custom grid menu within the custom race settings once you've set your car's ECU to a different value, or else the AI will then adopt your car's new ECU percentage, and you will be faster again in a straight line.
The AI has a bug where, after the first corner, they only use 97% throttle, and so they are effectively down by a chunk of BHP.
The issue with BoP is that it disables tuning so you can't adjust the ECU percentage. If you could BoP and still reduce your ECU percentage, it would be great, but alas. Some kind of custom race override would be nice if possible.
I recommend:
Boost Weak
95/96% ECU/Power Limiter percentage (depends on the car, slower cars sometimes need less of a reduction, faster cars often require more)
Boost Weak brings the field closer and reduces (I believe) the insane rubberbanding by the AI in which they slow to a crawl if they're too far ahead.
95/96% ECU/power limiter for your car is a good general value that will make it more competitive in many races.
Note that the power limiter hits torque harder than the ECU, so generally I reduce the ECU only if possible.
But a combo of ECU and power limiter can get you a little more BHP if the ECU reduction only isn't landing you in a sweet spot.