JC, Jacking up the pressure will have the same effect on run time as switching to a bigger tank(more air pumped in) which means it will run a little longer but you will have to wait longer for a recharge so nothing is gained, but I think you already know that. Over the years I have seen many, many times where someone raises pressure(believe it or not I know one guy who runs 250 PSI in his 40 gal tank on his service truck!) or adds multiple tanks in a futile effort to gain compressor performance. This may add some useful run time on tools like large impact wrenches when they are used for only a few seconds and then lay idle anyway giving the compressor time to catch up. On longer running tools such as DA sanders anything gained is lost during the recharge and over about a 5-10 min period the run time vs recharge time will be the same regardless and in fact on some really huge tank volumes such as 2 or even 3 extra 40-60 gal tanks on a 12-16 CFM compressor one may even lose performance due to heat build-up affecting pump efficiency. The bottom line is if the SCFM is insufficient to operate a tool the way you need it to then nothing you can do to your compressor, short of increasing pump CFM in some manner, will change that fact. A tool needs a given amount of volume over a given time to run properly and higher pressure or bigger tanks only store pump volume they cannot add to it so over any operating period that uses enough air to kick on the compressor more than once nothing can be gained from adding volume. Simple laws of physics.
Last edited by oldred; 08-23-2005 at 12:26 PM.