.......Torque (force) to remove the lug nuts is related to pressure and has nothing to do with flow (volume). See the formula below. However, you need to maintain the pressure at the gun when it is running and that requires sufficient air flow (volume). You may generate high torque when you press the trigger but it quickly decreases due to insufficient volume of air to maintain the pressure.
Put the lug nuts on with a torque wrench to avoid the issue in the future.
Torque (in-lbs) = (PSI x (Displacement per revolution of the impact in cubic inches)) / 2 (3.14)
Ah, science and math: think, calculate, repair. Or, just keep buying anything you can think of until maybe, perhaps, the problem magically goes away.
Thank you ford33 for your post and this formula.
To the OP: it's not your compressor! I have a 150 psi 25 gal Porter Cable branded compressor, and with a $25 Chinese impact I was unable to remove many bolt. I replaced it with a clear-out Porter Cable branded impact rated for 400 ft lbs and I've never been skunked yet.
1. Don't run your compressor on an extension cord, use a longer air hose if need be. Look at the thickness of your electrical cord, compare it to any extension cord you own. The voltage drop will put excessive heat and strain to the motor.
2. Look at the air regulator on you compressor when holding the trigger on your impact wrench. You'll see how much psi drops with a running tool. If you need 90 psi, you need while the tool is running, not static. So leaving your compressor set to 125 psi will probably do, bu check anyway.
3. The longer the air hose the more the pressure drop. Do you really need to use a 50 ft hose when removing lug nuts? Can you get by with a 25 ft hose? If so, buy one. You can switch lengths depending on what you're doing.
4. If you want to be precise, do like others have said and get a pressure gauge and install it on the working end of the air hose and check the pressure. This tells you what the air tool actually has available to use.
5. A larger air tank will allow your air tool to run longer before the motor needs to recharge, so you can run a tool longer without waiting for the tank to "catch up." A larger tank has nothing to do with amount of air delivered to the tool; that is related to pressure and flow. A 500 hp tankless compressor will deliver more air than a 1000 gallon 1 hp compressor.
6. Don't waste your money on larger fittings. It won't help. I too used a 5 gal pancake compressor with my air impact until I got my current compressor, and I was able to remove lug nuts without a problem. I could only hold the trigger for short period and had to wait frequently till the compressor recharged, but the air flow and pressure allowed the tool to do the job.
7. Remove the lug nuts by hand or take it to a shop and pay them to do it. Always reinstall lug nuts using a torque wrench.
