The 1.6 and 2.0 ecoboost will make more power and at what is advertised on premium which is 91, since it's the highest that some states have. So that's what they base it off of. If you use 92 or 93, you will have an increase in HP. Now with these cars, even a 10 HP increase at the crank, maybe 4-5 at the wheels...will you really feel that....no. Is it there...yes. The past cars that have EEC's that can not adjust timing, if they are recommended for 87, better use 87. unless it's tuned for it or has higher compression. Alot of the newer vehicles that have VVT or the i, they can actually sense the fuel octane and adjust the timing...with higher octane, more timing, more power. That's all VVT or VCT or so on does for you car...constantly adjusting timing for peak curve at all rpms while you are pushing the gas pedal.
Even seen this with Mustang GT's that have the VVT. They drained it, put 87 in. Made XXXrwhp. Drained it and put in 91 octane and it made 5rwhp more. Then they did a Mustang V6 the same way, didn't have VVT. It actually lost 5rwhp on the 91 octane, which makes sense. It can't adjust to the octane and 87 is more flammable than 91, so most of the gas is unburnt and just get's exhausted out. Which if you have cats, can damage them.
I think if you haul a good amont or tow, i would def use premium. The cost of 87 vs 91-93, i don't think it's worth it for normal driving.
2013 Escape SEL 2.0....212fwhp/236fwtq
2003 Cobra-Garage queen
2003 Lightning-GT500 TVS powered
2005 Expedition XLT-DD