I have the ARB twin compressor with a 5 gallon tank. The compressor maintains the system at 150psi. I have a regulator on the line I use for airing up tires set to 90psi. I don't get far into airing up the first 37" tire and the compressor kicks on and is running from then until I finish. It may take a little longer to fill all 4 tires than it did with the CO2, but not by much. I think the one time I timed it, it was about 2min-30sec per tire to fill from 12psi to 30psi.
In thinking back on filling tires, I think the needle generally holds about 40-60psi while I'm filling. Disclaimer being I don't know if the pressure on the dial at the inflator is accurate while filling.
Sorry I don't have math numbers but I thought maybe some real world experience would help process the numbers.
Thanks for that!

I found some good spec tables on the VIAIR website that converted CFM to Liters/Minute.... that was easy enough to convert to Gallons/Min.
From that original CK5 thread, I was able to do a rough estimate of tire volume on my 38's.... 42 Gallons per tire at sea level.

It sounds bad, but it's not really. If I was trying to get from say 12psi trail pressure to a likely road pressure of 25psi... I need 151 Gallons of air from the compressor / tank setup.
At the pressures I'd be working at, the VIAIR 400C will put out 16 Gallons per minute... and if I use 2 compressors I can fill all 4 tires (from 12 to 25psi) in just under 5 minutes.
(This assumes there is NO air tank in the system.... this is just 2 compressors pumping straight into the tires)
Where I'm stuck now is finding some kind of conversion that will explain how to convert a 2 Gallon air tank (@ 120psi) to a pressure like 25psi to understand how much effect it will have on those 151 gallons I need.... presumably, the tank will dump it's pressure just about instantly, and the compressors will then need to fill not only the remaining air needed for the tires, but will also have to "backfill" the 2 gallons of missing air from the tank once it purges itself into the tires???

Anyway, I feel like I'm getting pretty close to the answer.... I just need to find the next formula.
-G




