Needle scalers

Greetings guys;
I am contemplating repainting my basement floor and garage, both below ground. The floor was painted with Beher floor paint that really didn't hold up. Part of that is due to the original coating, that was still underneath, failing.
Here is what I would like to know. I am looking for a reasonable needle scaler ( used one in the Navy eons ago) to let me take up all the paint to bare concrete. I presently have a Sears home air compressor that will run rated at 3.7@90 on a small pancake tank.
I was looking at Harbor Freight but they run at 4 @ 90 and not to sure of HFs power tools. Anyone know of a decent scaler that will run below the 3.7? This scaler will also be used to remove old failing waterproofing paint in my below ground garage.
If not what is a decent compressor configuration setup that will run something like this?
Remember I need to keep cost down

 

I don't have any recommendations for a specific tool purchase but any type of air sander/grinder will eat a lot of cfm. You can run tools that use more cfm on a small compressor but only in short bursts. You'll either need to get a considerably bigger compressor or switch to an electric powered tool.

 

I would think any sort of needle gun (yes, I used them a lot also, along with knuckle busters) would cause quite a bit of damage to the concrete.

 

Thanks for the replies guys.
Gunguy, I remember how apply named those "knuckle busters" were! I was figuring on the low CFM tools to try to avoid that very thing, or else rig a depth guide to keep the striking light and constant. Then any concrete that comes up would have been failing also. This house was built around 1927 and it is a original floor. I was figuring on using some concrete repair on any places that failed. Anyone got any ideas to help in removing this old paint rather than a manual scraper?

 

I'd use a paint stripper and a pressure washer. You could also use a big 7" or 9" sander but I'd rather endure a few fumes than deal with all that dust.