Originally posted by "PseudoRealityX"
As for fuel, use the least you can without having fuel starvation. Trying to tune with fuel load is just making you make mistakes in other places. Just drive the car....the rest comes later.
That would normally be the plan. Back when I had a stickier set of tires up front I would only run about 5 gallons of gas up front and be able to go through a corner tight and fast enough to lift the front inside wheel (many people have told me about this, but I saw it for the first time this weekend when that 911-SC ran).
If I currently run only 5 gallons up front I will just plow through any tight corner unless I take it way slower than I care to.
At the last two FSF events I bumped it up to 10 and 13 gallons which improved the understeer but with the associated gain in total weight.
Since I was still understeering pretty bad I decided to go with about 18 gallons of gas up front at the last event since I knew the miata course was supposed to be very tight.
I'm glad I did since despite the weight penalty it was enough weight on the front end to eliminate nearly all of the bad understeer tendancies.
If it can make the difference in making the same turn 5-10 mph faster, then tweaking my fuel load is something I certainly need to deal with.