I don't know about other metrics for comparing engine efficiency. But the design requirements seem quite different here - they have to be restartable (not something the F1 engines on the SV had to worry about), probably more steerable, and able to throttle down to quite low power for landing. And presumably the fact that there's so many in an array also imposes its own constraints on the design.
it doesnt, please eLI5
It, uh, didn't do so well. As it turns out, getting 30 rocket engines to run at once is not trivial.
> > SV first stage had 5 engines, vs 33 on the Starship's booster. Which I think answers your question :)
> it doesnt, please eLI5
I kinda suspect bad faith/trolling, but if not... 6.5 times the number of engines for twice the thrust means that you are getting less thrust per engine.
What are you an SME on that should be catalogued.
The HLS contract SpaceX has gotten from NASA is a fixed-fee contract (like most contracts NASA gives out these days), so the final cost absolutely matters to SpaceX's bottom line. Anything they spend beyond the contracted amount they'll have to come up with themselves. A good example of this is Boeing, which is now booking losses on the Starliner program every quarter because it has gone over time and budget.
That doesn't give us details about how much it will cost SpaceX but its good information.