Gas
Safety Car
Joined: Aug 2017
Posts: 4,924
Likes: 2,334
From: Etobicoke (Toronto) Ontario
To be fair, what the 2012 owner's manual actually states is
"If the vehicle has the 6.2L V8 engine
(VIN Code W), use premium
unleaded gasoline with a posted
octane rating of 91 or higher."
(then some comments about using 87 Octane)
"If the vehicle has the 6.2L V8 engine
(VIN Code T) or the 7.0L V8 engine
(VIN Code E), use premium
unleaded gasoline with a posted
octane rating of 91 or higher.
For best performance, use premium
unleaded gasoline with a posted
octane rating of 93."
If your engine actually needs 93 octane to prevent detonation, then you should use it. If your ECU doesn't need to pull timing to prevent detonation when using 92 octane, then using 93 is a waste of money, and because it's got 10% ethanol, you'll likely get about 5% worse gas mileage. Ethanol has only about 50% the heat content of gasoline, gallon for gallon. The same argument holds for 91 octane. If you don't need it, it's a waste of money.
"If the vehicle has the 6.2L V8 engine
(VIN Code W), use premium
unleaded gasoline with a posted
octane rating of 91 or higher."
(then some comments about using 87 Octane)
"If the vehicle has the 6.2L V8 engine
(VIN Code T) or the 7.0L V8 engine
(VIN Code E), use premium
unleaded gasoline with a posted
octane rating of 91 or higher.
For best performance, use premium
unleaded gasoline with a posted
octane rating of 93."
If your engine actually needs 93 octane to prevent detonation, then you should use it. If your ECU doesn't need to pull timing to prevent detonation when using 92 octane, then using 93 is a waste of money, and because it's got 10% ethanol, you'll likely get about 5% worse gas mileage. Ethanol has only about 50% the heat content of gasoline, gallon for gallon. The same argument holds for 91 octane. If you don't need it, it's a waste of money.
