I was speaking to my local compressor shop and he was saying the champion or the Quincy both should not come with 7.5 hp motors. He was saying that those pumps are built to be ran with 5 hp motors. It's makeing the pumps run real hard and just like humans if you make them work hard they won't last long. Im still torn between the Quincy qt 7.5 and the champion advantage 7.5. I don't know why I'm liking the Quincy more. Is the mantiance for like a valve job more difficult because it has reed valves instead of disc valves?
I agree with this and it should be elaborated on. A 5 running the same pump will be quieter and last longer. If it is a different model pump than that may be a different case.
While I am a firm believer in some horsepower a 5 will get er done for auto body. A 7.5 on a size larger tank could well support a 2 or 3 man shop where there could be overlapping demand on occasion. Recovery is a zing with 1 operator on a big p-ump but if I am working regular I can auto body/paint a car or truck from 3 hp if I am thrifty and mind the cycle time.
You can sand till you are tired on 5, most of thre time a single cycle which means you start, it starts and you sand till about time the thing might catch up. With 3 hp I sand till it kicks on and till performance drops, say 120 or so, I take break and regroup, resume sanding at 165 as the machine kicks at 175 so when I resume the pump is running and the tank is full, run a couple, break a minute or 2, resume, probably run near 65%, maybe longer for half an hour.
I got a lot of tank, it depends a bit on where one starts etc but it makes a big difference if the pump is running 100% or 50. Larger capacity helps. Allows use 50% say on a 10 cfm comp, 12 would bump it to 60 or so and 2 stage and larger tanks leave a time/energy head room. My cycle may be 5 minutes, I should time it. Ideally would be a big gage on the wall.