I can't explain roll cage tubing prices. It always seems cheaper and easier to get in California. It's in the $5/ft range if you can find it.
Here's a different economics lesson:
We had 344 laps at MSR to the LeBarron's 135.
That's 250% more laps/seat time!
I try to get more mileage out of our race dollars. Literally, more laps on track.
We were at COTA a couple years ago and the entry fees were $2200 or 2300 for 2 8 hour days. That's $137.50 an hour.
A buddy was there and they lost a water pump belt and didn't have a spare $10 belt! That cost them $10 plus an hour and half or so of lost track time resulting in a $10+(137.5X1.5) = $216.50 belt. This is what I see many teams doing.
Now lets look at $/lap:
We snapped the crankshaft at Barber the race before MSR and built a fresh bottom end. That was about $350.00. We warrantied out our crappy house brand O'Reilly's clutch which is now a "Power Torque." They used to be Valeo clutches and lasted a LONG time. We've raced on those for almost 10 year. Call it $500 for the fresh motor and clutch swap. 6 tires were $150 each for a $900 total, new brake pads for because we hadn't changed them in YEARS and the old ones still look awesome, $400. New oil gauge with warning light and some other gauges maybe $100.
Le Baron $1047.14
The Le Baron was 150% more per lap than the Z.
We spent a lot prepping for MSR.
Our following race at Road Atlanta (4 weeks later), all we did was buy 4 tires and change the oil for about $700. That was all going great for about 12 hours when we thought we lost the whole transmission. Turned out to be the axle shaft but anyway we were in second up to that point and completed 259 laps.
$/lap = $700/259 = $2.70
Fuel and entry fees are not in any of these numbers. We typically burn 8-10 gallons per hour on a dry track. Towing I get about 10 mpg. There are a lots of other expenses going into race weekends than just the car.
As a team I think we spent more on accommodations and travel than the race at Road Atlanta.
He wad 5 drivers at MSR so the entry fee was $1475 compared to Road Atlanta with 4.
We knew going into MSR we would like to do Road Atlanta, Barber and NOLA all close together plus major holidays limiting repair times in the middle. So we tried to do as much prep as possible to reduce downtime between races for MSR. In those 4 races, we took out 2 transmissions, 2 oil pumps and pulled off 2 top 10 finishes.
We got a big ass chewing at NOLA plus an additional penalty Sunday morning at NOLA, the oil pump crapped out shortly after that. Midday 5th gear sounded like a "bag of hammers," and we still managed to finish 7th running several hours in just 4th gear.
1973 Datsun 240Z