Thanks for the feedback, Grim. I've found so much good information on this site and want to add to the expertise in whatever way I can.
It was an interesting weekend. Friday was a test day and I had to spend the morning clearing up some safety issues that came up in tech the previous evening (new rules and tighter inspections). After lunch my first driver went out and turned laps for 25 minutes as I collected data on fuel consumption.
The second driver (fast guy and first time driver for my team) was watching the AFR gauge and came in after 2 laps saying it was reading very lean at full throttle. We spent the rest of the afternoon chasing a ghost - replacing sensors and a fuel pump. Finally at 5pm when practice ended I mentioned the new 3" exhaust, which I didn't believe could make a big difference... well, it did! Fortunately my tuner works 15 minutes from the track and offered to drop by to look at datalogs. He ended up adding 15% more fuel to the table! I learn something new every day, but we lost the chance to truly test the fuel system. A test drive on the track access roads showed good AFRs, so I was less worried about racing the next day.
The forecast for race day had been 50 degrees and dry all week - until the night before the race when the forecast changed to 2-4" of snow! We arrived at the track early to prep and it was cold but there was no precipitation. The race started and we worked our way into the top 10. About an hour into the race the driver mentions that the low-fuel lights are on, then the engine stumbled and he dove into the pits. I was expecting the car to run at least 90 minutes so we weren't ready to fuel or change driver. Somehow we managed to get our gear on, fuel the car, and buckle in a new driver in less than 5 minutes (the minimum pit time limit).
So now we had to change our race strategy from 6 stops to 13 (losing 5 minutes of track time with each extra stop). Halfway through the 2nd hour the snow started.
We had the most amazing luck catching full-course yellow flags to fuel the car while everyone else was going slowly behind a pace car. Then the snow got so bad that they stopped the race at 11am. The cars came to pit lane and we covered them.
The snow wasn't supposed to let up for a couple of hours so we got some lunch and stayed warm in an enclosed trailer. Around 2pm the snow stopped and we were told that the race would start again at 3pm.
We kept turning laps and coming in for fuel whenever the lights came on. The track conditions didn't change much - cold and wet the entire time.
When darkness fell (we were scheduled to go until 10pm) the fog rolled in. I finally got a chance to get in the driver's seat at 7pm in the dark and fog. I spent most of an hour in the car in a line behind a pace car because cars kept crashing and flying off the track. I think I eventually got 5 laps at speed and it was scary - the fog made it impossible to see landmarks, corner stations, flags... anything at all. They finally made a decision to stop the race at 8pm.
The car drove onto the trailer and we finished 8th overall out of 80 cars. That's a win. Without the fuel problem we may have contended for the win.
An opportunity came up today to race at the same track next weekend. Another week of thrashing starts tomorrow.