If water is the better cooler then that's what I'll stick with. I started running rich after the boost controller went on so I don't need the AFR enrichment that the meth provides. Yes, I run an intercooler BTW. I'm trying to dial in my boost controller just right and at the same time, obtain the optimum water/meth mixture for the desired 13psi (hi boost). The AFR is looking better on 100% water tho - about 11.1 @ 12psi. I'm trying to stay out of the 10 range on the wideband. God help me if I get close to 12 tho