What kind of gas will the ATS use? Premium or Regular?

[groundeffx]

I would just use premium. Not because people say you get better mileage. Not because people say it makes it run faster. But mainly because most premium gases don't have ethanol mixed in. Also premium gases can remain stable in your tank way longer than regular gas. Meaning if ever for some reason you're unable to start it up for a long time it wont gunk up the fuel lines.

premium gas has the same amount of ethanol as regular.

[tedATS2T]

The ATS works fine on regular gas. Remember Cdn regular is generally better octane than U.S. regular.
I bought my ATS after 25,000km of rental use and you can bet it never had any super going into it.
Sometimes COSTCO premium is only a few cents more expensive than regular so when I'm at Costco,
I fill up with super. Honestly, I cannot feel the differnece. 4 cents worth.

[James]

As an ATS coupe owner, I have used premium gasoline from day one; it costs me around 5.00 max over using regular. I was obliged to use regular when running short in the boonies and the result was engine knock when the car was pushed. Under normal, Interstate conditions, it made no difference but gas mileage fell by a couple of miles to the gallon. My previous vehicle used a Ford V8, the Euro design used in the Lincoln LS. It needed premium as regular certainly caused a drop in performance. Regular gas can be used in the ATS but premium does ensure no knocks and a seemingly smoother ride from an engine that can be rough at the top end.

[Lonestranger]

True most of todays computer controlled engines can run on either regular or premium fuel. However, the ATS with the 2.0T package was designed to run on premium fuel (91 RON or Higher) . The performance is primarily based on the intercooled turbo package it utilizes to get its HP and Torque figures! When lower octane fuel is used, the computer will/must retard the timing to control engine knock and possible engine damage. Additionally it will affect the fuel mileage figure. You are already asking a rather small engine to pull around a full size car, not a mini! Regarding cost difference of regular to premium, it you have a Sam's Location w/fueling, they normally have a much smaller "upgrade" in price, between grades than at "regular" gas stations. eg: .19 -.20/gal vs the .80 to .90/gal at "regular" stations. Our mileage difference between regular and premium fuel averages 2 mpg with both our ATS and our Escalade. Both run measurable better on premium. Just saying, your choice - Happy Motoring!