[FED 387]

Are you using a 10 oz bottle??? If so it should be between 1200-1500 pounds pressure when full---Weigh it totally empty and again after you fill it to make sure that you have a full tank. Note the weight difference between a full and empty tank--The shifter will operate OK between 50-110 pounds pressure----Temperature also has a lot to do with how much pressure you actually have in the tank---if it shows 1200 and it is 80* outside when the temp drops to about 60* you might only end up with 800-900 pounds----Try using nitrogen it is less susceptible to temeprature change but it costs more to fill it too---After you fill the tank and reinstall your regulator ALWAYS put in a new gasket-The plastic ones will work OK but they really are too hard to seat well--Ask the guy who fills it to give you a handfull of them--whenever you turn on the air bottle always turn it fully on helps cut down on leaks and if you are driving down the return road turn it off no need to keep pressure in it if you are not using it less chance of leakage too----You should be able to get a few weekends out of a 10 oz tank but you really need to have a spare "just in case"----Some of my observations from my experience at the track---Comp 387