Your profile says you have an 03 F7, I have the same sled, usually run mine about 42-43 pounds at wide open throttle. Start wth the needle valve seated lightly, then back it out 2 1/2 turns, warm up the sled, raise the rear end with an approved or known safe jack stand, give it a blast full throttle while watching the pressure on the gauge, try and get a baseline reading, then gradually decrease pressure (turn in needle) until you have your desired pressure. Remember, not all efi's act the same, one may be rich, where another will be leaner, learn to read your plugs, and don't turn it in say more than a half turn at a time. The best way to effectively use these and be safe is to put your sled on a good dyno that can give you fuel consumption readings (bsfc, lbs/hr) and tune it in a little at a time. One more item to consider, the colder the ambient temperature, you may get a false reading on the gauge, could be lower than it really is, so be cautious and don't squeek your ride, hope this helps.