I finally created an account on here to ask the question. I have tried to read multiple threads and I don't really know if I'm getting a concrete answer so I thought I would finally ask on here since this seems to be the most skilled website on air compressors by far.

I used to be a mechanic and I still love doing projects on the side but I think it's finally time for me to get an air compressor to help with small projects.

I have been looking at two air compressors right now. One is a 5.5 gallon tank with 2.2 CFM @ 90 and the second is a 4.5 gal with 5.1 SCFM at 90. The 2.2 CFM one is half the price of the 5.1.

I plan to use the air compressor to power my impact gun. But it will only be used for rare occurrences. For instance if I have difficult bolt I want to be able to hook up my impact gun and see if that helps. Or to speed up a project by using the impact gun just to take off a single tire if I'm working on the side of the vehicle. I have come to the conclusion that higher SCFM is great for impacts but I have the understanding that this is only required if I'm going to be using it continuously. Which in my case I am going to be using it seldomly.

Will the cheaper 2.2 CFM work just as well as the 5.1 for supplying my impact gun air for removing a difficult bolt if both air compressors are completely full? If I was planning on doing a lot of work with the air tool I could understand going for the 5.1 but if the seldom amount of time I'm going to be using an air compressor, obviously the cheaper one would sit with me better.