http://en.wikipedia.org/wiki/Raptor_%28rocket_engine%29
Raptor is the first member of a family of methane-fueled rocket engines under development by SpaceX. It is specifically intended to power high performance lower and upper stages for SpaceX super-heavy launch vehicles. The engine will be powered by methane and liquid oxygen (LOX),[2] rather than the RP-1 kerosene and LOX used in all previous Falcon 9 upper stages, which use a Merlin vacuum engine. Earlier concepts for Raptor would have used liquid hydrogen (LH2) fuel rather than methane.
The Raptor engine will have over six times the thrust of the Merlin 1D vacuum engine that powers the second stage of the current Falcon 9, the Falcon 9 v1.1.
The broader Raptor concept “is a highly reusable methane staged-combustion engine that will power the next generation of SpaceX launch vehicles designed for the exploration and colonization of Mars.”[3]
Thrust (vac.) 4,400 kilonewtons (1,000,000 lbf)[1]
Isp (vac.) 363 s
Isp (SL) 321 s