I have a co-worked that uses 87 octane in his 6.2 Denali and says it runs fine and doesn't ping or knock even while towing. I'm not sure what year his is, but my 2010 owners manual says to use premium, so that's what I have always done.

Anyone else use 87 octane in their 6.2?

My 08 owners manual says to run 91 and i may see decreased performance and efficiency with 87 but that its safe to run it as long as there's no knocking...

So NO... i'll pay the extra $3/tank to run what my engine was designed to run most efficiently. It's a Denali... not a Vega....

Thats it to, 3 bucks more for the better fuel only way to go

E-85

run 87 in mine for 1500 miles. only getting 12.5 mpg. Going to switch to 93 and see what happens. No knocking on 87 either.

Good Luck,

Jason

Gentlemen,

The computer will dial back the timing for the lower octane. This reduces power and fuel mileage. I bet it does not actually cost more to run premium because of the gas mileage gain.

Ken

true Ken, I run E-85 and get 10 and 16 with 92. It seems to have more power with E85 though.

If your above 4000ft you can run 87 in place of 91 and 91 would be like running 93, and 85 would be like running 87.

switched to premium and now getting 15 to 17.8MPG

what were you getting on 87/89?

Hi guys....I'm new to the forum and just picked up a 2010 Silverado 1500 Crew Z-71 6.2/3.42 yesterday. The dealer filled it with 87 octane and coming home from the dealer - about 40 miles with a mix of 70-75 on the interstate and two lane back roads, I got 16.1 mpg. This is with 25 miles on the clock. With my 07 Titan that I traded in, even with an egg between my foot and the pedal, I couldn't of gotten this. Didn't get on it yet, but I can tell this 6.2 has plenty

Been reading this forum for a while and just wanted to drop in and say hey.

Bob

Welcome.

Id atleast run Mid-Grade in it.

Welcome Bob!

On the topic at hand you are fine as was mentioned above to my understanding. These engines as with the 6.2L that's in the Camaro, the computer will figure out what you're running and recalibrate accordingly. You will lose some HP but it will not harm the engine.

Now the 2010 Denali 403hp 6.2L V8 recommends premium fuel, but regular is safe? I'd like to know for the 2007 380hp 6.2L if this is the same requirement.

Alright now sure how it is down at sea level but here is a rough estimate:


Premium Fuel: 93 or 91 Octane = Premium
Mid-Grade: 89 or 87 Octane - Mid Grade
Regular: 85 or 87 Octane = Regular


Up here at 5280 ft above sea level, we have 3 choices. 91, 87, and 85.

91 is like 93 down at sea level
87 is like 89 down at sea level
85 is like 87 down at sea level

Anybody know what would be the recommended fuel for a 2007 Denali XL?

Its the same