A regulator like that one in the pic would function like a pop valve, but smoother. Just drilla little hole in your tank and thread that in and set it for whatever pressure you want the tank to stay at, and pua check valve in the line form the exhaust to the tank, and you should have a constant pressure from full to empty....

Anyone know where to get a price on that little regulator??

And does anyone have a pressure tester taht would be suitable for less than 20 PSIg?
We would need to know what the tank pressure is while the truck is running good, and set the regulator at that.


Good find on that reg, dogman. Never seen one that small.