It would be nice to have a small calculator window inside the pit window to do fuel calculations and such. I alt tab to the windows calculator a lot, and it seems like it would be a nice addition to have.
hmm, just use a small handheld calc... But I can't see a reason for scawen to put time and effort in there. I am by no means a math genious, but calculating the amount of fuel I'll need to go a desired number of laps is done in mere moments in my head. It's just simple multiplication.
CTRA's X-System does indeed have an automatic fuel calculator which uses both online fuel use databases and, I think, the CTRA's own database, for every track and car on the system.