Re: 110%
Engine output is also calculated at a specific altitude at optimal fuel/oxidizer ratio and the turbo pumps running at designed optimal head pressure and flow. By increasing the rocket chamber pressure and thus making the pumps run at slightly above optimal settings engine efficiency (specific impulse) is slightly increased lower in the atmosphere. IIRC the space shuttle engines were designed to run at 500.000 lbs of thrust, but design optimization resulted in them running at aprox. 540.000 lbs (108%) and they could actually throttle to 115% (Which they would only do if the shuttle lost the center engine in the later stages of launch for a once around abort or abort to orbit).
Biting the hand that feeds IT
