It's 8,000/10,000. My welder uses 7200 at max.
In general, I only need the 8,000w size for the inrush, and then welding is just a minute or two on, then off for awhile It doesn't labor all day at 8,000W. It's mostly just the engine running and needing to cool itself for all the noise it makes.
Well today I did a little testing. I directed to duct towards the "intake" end of the genset, that's all I could do with what I had (time & materials).
With it closed up, (& 435CFM fan running as shown) the temperature quickly rose to beyond the range of the thermometer. The load on the generator is 160watts of lights, a 40A battery charger. So the generators barely working at all, just running it's engine.
I ended up running it like this, with the plywood just to deflect noise. There's snow on the ground, this can't work in the summertime. Gonna need a lot more flow, I'm wondering if 1500CFM isn't enough. Maybe in the summertime it just can't be in the vault. I think I'm going to have to use one of my signal wires for a remote (temperature) alarm.