I lasted 25 laps at Five Flags Speedway practice session tonight. I was trying out FFB at 50% and it actually helps a lot in term of car control. However, the car is still getting loose off of exit in between 25 to 31 laps into the run. Let me know what you think!
Ok so from what I can tell, this is what is happening. The fuel sits to the rear of the car adding a lot of weight when it is full and the longer you go in the run, the more fuel you burn off and the lighter the rear end becomes which makes you loose.
btw download the spring tuning chart and setup matrix from this link. They have good general advice.
There are several things you can try but in the end you will have to just choose one because each option has tradeoffs.
You could lower the RR spring rate, but this will tighten you up mid corner. Probably not the best option.
You could lower the RR track bar, which might be your best bet. You will be tight off, the first few laps but should loosen up on the long run.
You could lower your RR bump stiffness by 1 or 2 clicks but i'm not sure that will help on the long runs.
You could also lower RR tire pressure but temps look pretty good.
Same thing for stagger, lower RR stagger but again not sure this is the best thing for you.
I would try lowering the RR track bar first and see if that makes the car too tight for you.
If that is too tight, I would put it back and then maybe lower the stagger or RR tire pressure or both. I'm just not familiar enough with how much stagger will tighten up the car.
If those don't work I would try a combination of some of these, i.e. lower the RR track bar 1 click but raise stagger 1 click. Or Lower the RR spring but raise RR track bar. You are basically trying to find that balance of being too tight and too loose.
The bottomline is that as you burn off the fuel, the RR becomes light and then your car loosens up.
The only real remedy is to start the car off being a little tight and letting it loosen up over the long run.