Just bought a 2013 fx sho with 224 hours in good shape from a dealer and inspected. It’s running 6500 7000 Max at 60 max mph. It seems like it has more but never does and I’m running it on 93 octane for the first 2 rides. You think when the gas is up and I refill the tank with 87 of the tuned suggestion it’ll get those numbers up to what the normal numbers of other peoples comments are gettingRunning 93 octane in your ski if its not programmed flashed for 93 will slow it down. The ecu is tuned for 87 octane dockside crappy gas that probably has water in it already. Its such a conservative tune that with a MoTec and a few tweaks you can unleash a lot of power by just changing fuel specs.
Using 93 is not only a waste of money but you lose performance if the tune or cylinder pressure doesn't mandate such use. The engine runs at such low temps, the cylinder head doesn't have the same hotspot issues that cars have running coolant, so the use of a high-test fuel is negated completely. It also requires much more cylinder pressure to extract the same thermal btu energy from higher octane fuel and with the low boost levels and conservative timing program, you will lose power with 91+ octane fuels.
I can back it up with 15+ years of dyno tuning cars, boats and aircraft. Do the research... 93 octane fuel is a hype that fuel retailers take to the bank.