What octane gas?

ymc226 · October 19, 2016

I read the manual and it stated Top Tier gas brands were recommended but no specific octane. Just bought a 2016 LT Suburban with the Luxury package. Previously used just the cheapest regularly (87 octane) gas on my 2008 LTZ.

Andy Seibel · October 19, 2016

well if its the luxury package, you should probably use premium gas...

j/k. I would still use regular unleaded just like every other engine that is not a tuned high performance machine.

I'm sure we'll hear from others who swear they get better performance from the premium fuel, so buy whatever you want.

newdude · October 19, 2016

87 is perfectly fine as its what GM recommends for the 5.3. No need to run anything further.

O_J_Simpson · October 19, 2016

Read further.

5.3L 87

6.2L Premium

Dnt · October 20, 2016

Do NOT be buying up all the Premium fuel I need that stuff!. I like 93 octane from any supplier off the top tier fuel list for my tuned 6.2. Runs like a friggin Banshee and gets awesome gas mileage.......

I ran a lot of E85 through my 14 5.3 and never even considered top tier as being important just bought the cheapest stuff available whether E85 or regular 87 octane. The 5.3 really liked anything that I fed it, but the fuel mileage does suffer a bit on the E85.. I guess that is a BIg advantage in staying with the 5.3 engine if you are on a tight budget..

Edited October 20, 2016 by MyFavTruck

The Zip · October 20, 2016

I read the manual and it stated Top Tier gas brands were recommended but no specific octane. Just bought a 2016 LT Suburban with the Luxury package. Previously used just the cheapest regularly (87 octane) gas on my 2008 LTZ.

From the Chevrolet manual, page 9-70; "Use regular unleaded gasoline meeting ASTM specification D4814 with a posted octane rating of 87 or higher. Do not use gasoline with an octane rating below 87, as it may cause engine damage and will lower fuel economy". I use 89, but as long as you don't use below 87, no where in the manual does it say the truck will perform better with anything higher.

redwngr · November 2, 2016

I read the manual and it stated Top Tier gas brands were recommended but no specific octane. Just bought a 2016 LT Suburban with the Luxury package. Previously used just the cheapest regularly (87 octane) gas on my 2008 LTZ.

'Top Tier' is a certification of gasoline and additives, not of octane level.

National brands and larger regional brands will all have the certification. Discount independents may or may not.

http://www.toptiergas.com/

Some don't wish to pay for certification and may have the full package without it.

It's unlikely that a single tank of top tier, or a single tank that isn't would be noticeable to most.

Edited November 2, 2016 by redwngr

TheHauler · November 8, 2016

I usually get the highest one but thats cause I need all the performance. If gas prices are too high though I then get regular

Wrench589 · November 26, 2016

It's very important to use the recommended minimum octane in the engine, even today's modern engines with knock sensors. The 5.3L only needs 87 octane but the 6.2L needs 91 octane minimum.

As for using a fuel with a higher octane rating that required, well that's a complicated discussion. Some people believe higher octane fuels burn "slower" and hence will actually reduce performance in a engine that doesn't require higher octane fuel. That's true and not true. For retail pumps fuels, not really true. It is true for racing fuels, though. Racing fuels are not a good idea in your grocery getter!!

Some folks believe there is a difference in heat content (BTUs) between the different grades of octane fuels. And hence, a difference in the power gained in the engine. There is some truth to this, as it turns out. But, the difference is very small. More importantly, it's not always directionally consistent. In other words, with some brands, their high octane has slightly more heat content than their low octane; some brands it's the other way around. And, even within a brand, it will vary seasonally as well as regionally depending which specific refinery he fuel s coming from. So unless you want to carry around a BTU tester, it's virtually impossible to take advantage of the difference.

The octane rating itself will not produce more power in and engine that doesn't need it.

Yet some people are convinced their vehicle runs better on high octant (premium) fuel. BS? May not be. Some brands use more additives in their high octane fuels than the lower octane. Things like detergents to keep the injectors clean, anticorrosion additives, stabilizer to keep the fuel from degrading and vaporizing in the tank, etc. And some vehicles are more sensitive to the fuel and buildup on the injectors. So, by buying the higher octane fuel, you end up getting a higher quality fuel which can be helpful. Which is the point of the top tier fuels. These are higher quality fuels. And that DOES make a difference. At least for some vehicles. No way to know which ones, so buyer beware. But I would rather error on the safe side and only put high quality fuel in my vehicles. Unless your driving a huge number of miles a year, what's it really cost extra? JMHO.

markitzero · November 27, 2016

I've been using mostly top tier 87 in my 2016 Suburban but the one thing that has bothered me is the idle being rough. It's not concerning but I am just accustom to perfectly smooth idling vehicles and this is not one of them. I filled with a tank of ethanol free 87 and immediately noticed a smoother idle. I was considering trying a tank of premium ethanol free to see if that makes any difference.

Driver72 · December 3, 2016

Do NOT be buying up all the Premium fuel I need that stuff!. I like 93 octane from any supplier off the top tier fuel list for my tuned 6.2. Runs like a friggin Banshee and gets awesome gas mileage.......

I ran a lot of E85 through my 14 5.3 and never even considered top tier as being important just bought the cheapest stuff available whether E85 or regular 87 octane. The 5.3 really liked anything that I fed it, but the fuel mileage does suffer a bit on the E85.. I guess that is a BIg advantage in staying with the 5.3 engine if you are on a tight budget..

Which tune are you using?

Driver72 · December 3, 2016

If you have the 5.3 just use 87 Octane if you go to a top tier gas station.

If you have to fill up at some cheap-o no name brand discount gas station, you may want to throw in 89 Octane just to offset the craptacular discount gas.

Edited December 3, 2016 by Driver72

TJay74 · December 3, 2016

While the 5.3l does state 87 is to be used, most of the data logging on the 5.3l has shown they really should be running 89 or even 91. My 6.2l sees nothing other than 91 or a mix of 100 and 91 to get me to 93/94 octane since Oklahoma doesn't have 93 octane anymore.

Dnt · December 3, 2016

Which tune are you using?

Hypertech max energy 2.0 part 2000. Really only bought it because it allows you to set a speed at which the AFM only comes on above. I have the GM Borla catback exh and the AFM at low speed irritates me. The Hypertech has 2 options for tune Premium fuel tune and a Regular fuel tune. I ran the premium fuel tune for about 5000 miles with only 93 octane. Got bored so just changed to regular fuel tune and put in a tank of top tier 87 octane as a test. I am getting an occasional click when in 4V at very light throttle around 58 to 62 mph. Next tank will be top tier 89 octane to see if the occasional click goes away. Looks like the verdict is DO NOT USE 87 OCTANE with a 6.2 no matter what tune you use! Truck has around 11,000 miles on it so figured it was broke in enough to experiment on a bit.

mostly city driving with loooong remote start warmups, the Denali DIC calculates overall average speed so that is why the 39mph average. that always seems to throw people off....

Edited December 3, 2016 by MyFavTruck

Wrench589 · December 3, 2016

Hypertech max energy 2.0 part 2000. Really only bought it because it allows you to set a speed at which the AFM only comes on above. I have the GM Borla catback exh and the AFM at low speed irritates me. The Hypertech has 2 options for tune Premium fuel tune and a Regular fuel tune. I ran the premium fuel tune for about 5000 miles with only 93 octane. Got bored so just changed to regular fuel tune and put in a tank of top tier 87 octane as a test. I am getting an occasional click when in 4V at very light throttle around 58 to 62 mph. Next tank will be top tier 89 octane to see if the occasional click goes away. Looks like the verdict is DO NOT USE 87 OCTANE with a 6.2 no matter what tune you use! Truck has around 11,000 miles on it so figured it was broke in enough to experiment on a bit.

mostly city driving with loooong remote start warmups, the Denali DIC calculates overall average speed so that is why the 39mph average. that always seems to throw people off....

Well, GM does recommend minimum. 91 octane for the 6.2L so no surprise your testing confirmed that. When you say "clicked" are you talking about audible knock, or detonation being picked up on the engine management system. Does the Hypertech let you monitors PIDs like knock?