Fuel economy.... regular (87 octane) vs. premium (93 octane)

[Mr. Wonderful]

My previous car was a 2018 Genesis G80 Sport with the same 3.3 as the Stinger.
I used only 87 octane and encountered no problems doing so.
I will continue to use regular fuel for this reason:
I mainly get gas at Costco. Today, their price for regular is $2.59, premium $2.99.
That is a 15% difference in price.
I would have to get 15% better mileage by using premium than regular just to break even.
I'd have to get over 15% better mileage to make buying premium a good idea related to
fuel mileage.

 

[eflyguy]

I got the best fuel economy I have seen on a 500-mile road trip using 87 yesterday.

I'm not saying it's better than premium. Cost is not a factor. I simply wasn't going to be needing full performance.

I would not put in 87 if I was headed to the drag strip, or to the mountains for a day of spirited driving.

 

[Stevizzle]

I only use Shell because I get $0.15 off a gallon, but they only have 87, 89, & 93. The difference between 87 and 93 is $0.62 per gallon, which would cost me about $8 more per fill-up.

I've only had mine for just over 2 weeks and the dealership filled up the first tank, with what I assume was premium, however, they were the ones who told me regular was fine so I will never know .

My true mileage on the first tank was 21.5.

I used 87 on the second tank and my true mileage was 22.5.

I just filled up yesterday with 93 just to conclude this very unscientific experiment.

I will update this next week, but I've been pleasantly surprised with the fuel economy thus far and read that it improves after break-in .

 

[NS_Stinger]

I can't fathom this logic. Why buy a twin turbo v6 performance car when a 15% difference in fuel is even a consideration?

 

[DaJackson]

Gas. 87, 91, 93 Octane?