2017 6.2 fuel?

SkiDooNick700 · July 7, 2017

Shell 93 octane only.

One of your more believable MPG pics ??

I use 93 as thats what most stations have aroud here for premium.

Dnt · July 7, 2017

One of your more believable MPG pics

I use 93 as thats what most stations have aroud here for premium.

Haha well now Ski she has not been completely broken in just yet. Only at 2500 miles, should be approaching that magic 30mpg goal soon I am sure....

rackaddict82 · July 7, 2017

...and that's why GM recommends 91 octane or higher...

91 octane is the highest octane gasoline I can buy in my area. Should I be using an additive to boost the octane?

newdude · July 7, 2017

91 octane is the highest octane gasoline I can buy in my area. Should I be using an additive to boost the octane?

You should be fine with 91. It does appear that GM did change the recommended octane on the 6.2 from 91 to 93. I went back and checked 2014, 2015 and 2016 manuals and they all had 91 or higher listed for 6.2. I'd put 91 in it and see what happens.

From the 2014-2016 books:

If the vehicle has the 6.2L V8 engine (VIN Code J), use premium unleaded gasoline meeting ASTM specification D4814 with a posted octane rating of 91 or higher. Regular unleaded gasoline rated at 87 octane or higher can be used, but acceleration and fuel economy will be reduced, and an audible knocking noise may be heard. If this occurs, use a gasoline rated at 91 octane or higher as soon as possible. Otherwise, the engine could be damaged. If heavy knocking is heard when using gasoline with a 91 octane rating or higher, the engine needs service.

From the 2017 book:

For the 6.2L engine, premium unleaded gasoline meeting ASTM specification D4814 with a posted octane rating of 93 is highly recommended for best performance and fuel economy. Unleaded gasoline with an octane rated as low as 87 can be used. Using unleaded gasoline rated below 93 octane, however, will lead to reduced acceleration and fuel economy. If knocking occurs, use a gasoline rated at 93 octane as soon as possible, otherwise, the engine could be damaged. If heavy knocking is heard when using gasoline with a 93 octane rating, the engine needs service.

Again, I'm not sure why GM made such a change.