So I just put the AirDog 100 on my truck and I was wondering if you could put a bigger sping in the return line. I put the 17 psi one in but could you go bigger. I know if you go to much it will hurt you so whats my limit.

 

It is not supply pressure at idle that you should be worried about but the pressure or flow that you have under a load or at WOT. If you are holding 13-15 under load or WOT you should be fine and not need a bigger spring. My 150 pushes 18-20 at idle but I can pull it down to 12 at WOT under a pull.

 

Correct. More pressure is not always the answer, since it's a measure of restriction not flow.