You hit the nail on the head with the CFM being the problem if your DA won't keep up since tank volume has very little to do with it although a lot of people will not accept this fact. A higher shut-off pressure does exactly the same thing as a bigger tank, that is store more cubic feet of air. I have been building and installing air systems as part of my welding business for over thirty years and I guess pressure and tank size has been the biggest misunderstanding I have had to deal with. It seems a lot of people think higher pressure and/or a bigger tank will help an undersized compressor keep up with an air hungry tool but this is not true since it is the CFM capabilities of the compressor pump that determines if it will keep up or not and the start/ cut-off pressure and size of the tank simply controls the on-off cycle rate. Any extra run time gained by increasing cut-off pressure/using bigger or multiple tanks is immediately lost to the extra time it takes to recharge the bigger volume so it is a trade off and you gain nothing. Cut-off pressure/tank size is chosen based on expected demand so the cycle times can be set to allow a proper cooling period for the pump within normal operating range and demand should not be exceeded for extended periods. If a compressor will not keep up with demand then it's CFM capabilities are being exceeded and about the only solution is to go with a bigger compressor since changing storage volume by upping the pressure or adding tanks will only change the cycle rate and do nothing for compressor output in spite of common belief, it is simple laws of physics that you can get no more out of a tank than you put in no matter what the pressure or size.
Last edited by oldred; 08-22-2005 at 02:28 PM.