For upside down car work try quite a bit more wire feed. Try a steeper than normal torch angle too so that the torch is quite far from vertical.
Don't go mad with gas, just set it correctly as someone already said.
Cleanliness is everything on car work and difficult to achieve, do you best to get everything clean.
You earth doesn't have to be especially close but needs to be clamped tightly onto clean metal and is a common problem, try to keep it on the same panel or your earch path is via a load of spotwelds, itll work but why increase the chance or resistance.
I usually weld a tab of clean scrap steel on to attach the earth clamp to, much easier.
Don't go mad with gas, just set it correctly as someone already said.
Cleanliness is everything on car work and difficult to achieve, do you best to get everything clean.
You earth doesn't have to be especially close but needs to be clamped tightly onto clean metal and is a common problem, try to keep it on the same panel or your earch path is via a load of spotwelds, itll work but why increase the chance or resistance.
I usually weld a tab of clean scrap steel on to attach the earth clamp to, much easier.