July 28, 2017 at 12:19 pm
#168390
Participant
You can probably use 91 or even 87. Check your owner’s manual. In my owner’s manual (2017 CT6) , for the 2.0L Turbo, premium fuel is recommended but not required. Using a lower octane will result in lower engine performance as the computer will dial back to protect the engine. You probably would not notice any loss in economy. My previous 2014 CTS had the 2.0L Turbo and I was very satisfied with the preformance and got 25mpg overall economy in two years of driving. I used both 87 and 91 octane.