More nitro means richer mixture. Fuel dragsters use lots of nitro and fuel line that looks like garden hose!
You haven't been involved in the sport in a while have you? Now they have fire hoses, and ignition systems that look like the innards of a nuclear bomb to ignite that extremely rich mixture. They now have enough spark that the limiting factor is hydralic lock, from pumping in so much fuel that it won't fit into the combustion chamber.