The Raptor engine isn't just "more powerful" but uses an advanced "full-flow staged-combustion" cycle which has never flown before. The Merlin is highly optimi

The Raptor engine isn't just "more powerful" but uses an advanced "full-flow staged-combustion" cycle which has never flown before. The Merlin is highly optimized but it uses a simpler "gas generator" cycle which is less efficient. The Falcon 9 and Merlin is famously optimized for "low-cost" instead of "high-tech" but with Raptor they are now advancing the state of the art in propulsion tech.