Am curious what others are getting for mpg on their 2019 turbo CX-5's.

I'm in the 600 mile "break in" period of my 2019 Signature. On a 160 mile trip last weekend I averaged 33.8 mpg. It was on a mix of 87 and 91 octane gas, but mostly 87 octane because I had just filled up the tank. Am trying to determine if using 87 octane affects mpg, operating efficiency, engine noise, etc on the car. Honestly, I can't tell much of a difference between 87 or 91 octane but would like others to comment if they have other opinions. Thanks to all in advance.

 

Car and Driver says using 91 octane gives about 20 addl hp to the turbo - " In the CX-5, it makes 250 horsepower and 310 lb-ft of torque (that's if you use premium fuel; as with those other models, Mazda quotes a lower output of 227 hp on regular gasoline)" See https://www.caranddriver.com/news/a2...e-photos-info/

 

Going Westbound on my 2019 CX-5 GTR (turbo) gets 25+ mpg average on interstate through IL, MO, OK, TX on 87 Octane gas and adaptive cruise control set to 70 or 75 in IL and MO, and 75 0r 80 in OK and TX. In NM where the lowest grade gas is 86, I filled it up with the midgrade 88 Octane. On I-40 to Arizona, with adaptive cruise set at 80 mph, I got 26+ mpg with a head wind hitting the left front side of the car. So I guess, there is a mpg improvement when filling it up with higher octane fuel. Coming the opposite direction after a week in Arizona, I got 31 mpg through NM with the 88 octane gas and tail wind on the back right side of the car.

 

Definitely run a turbo engine on US 91 grade fuel.