The fuel efficiency is another benefit both in terms of cost and utility. Both Sierra airplanes have substantially better range than the originals, thanks to higher cruise speeds and more efficient engine design. According to Sierra's numbers, the Super II has an NBAA range of 1,775 nm, a 397 nm improvement over the Citation II, and its 400 knot max normal cruise speed is 45 knots faster than the unmodified airplane. The Super S-II has an NBAA range of 2,300 nm, which is 461 nm better than the S-II, and its 420-knot typical cruise speed is 35 knots faster than the already fast Citation II's 385-knot figure. With the Sierra mods, max fuel payload is especially noteworthy in the Super II, which has 1,278 pounds of payload compared with just 328 for the Pratt-equipped Citation II. The Super S-II improves on the S-II's 1,036-pound max fuel payload by better than 400 pounds.