Jump to content

What octane gas?

ymc226
 Share

Recommended Posts

ymc226 Enthusiast

ymc226

Posted
Posted

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 Enthusiast

Andy Seibel

Posted
Posted

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.

Dnt Senior Enthusiast

Dnt

Posted
Posted (edited)
post-127028-0-28094300-1476485477_thumb.jpg

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 by MyFavTruck
The Zip Senior Enthusiast

The Zip

Posted
Posted

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.

  • 2 weeks later...
redwngr Senior Enthusiast

redwngr

Posted
Posted (edited)

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 by redwngr
  • 3 weeks later...
Wrench589 Enthusiast

Wrench589

Posted
Posted

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.

  • Like 1
markitzero Enthusiast

markitzero

Posted
Posted

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 Enthusiast

Driver72

Posted
Posted

 

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 Enthusiast

Driver72

Posted
Posted (edited)

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 by Driver72
TJay74 Senior Enthusiast

TJay74

Posted
Posted

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 Senior Enthusiast

Dnt

Posted
Posted (edited)

 

 

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 by MyFavTruck
  • Like 1
Wrench589 Enthusiast

Wrench589

Posted
Posted

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?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      I will be doing that for sure, but I need to solve who has/ where I can find a bidirectional scan tool that will support OBD 1.5. I'm kicking myself because I ebay'ed a Snap On MT2500 that I didn't think I'd ever need anymore. D'oh!! I'd rather not buy another, so I'll contact a few local shops to see if they have one and how much they'd want to do the procedure. I'd rather have the ability to do it myself... I wish there was a modern tool that could do it all, but I'd have no idea what to buy.   The theory with the pulled timing is that it mimics a rich condition. The delayed spark causes incomplete burn and the O2 sensor picks up low oxygen levels. That's interpreted as a rich condition so the PCM pulls fuel and that shows up in the deeply negative fuel trims.
    • Chuck FB
      Joke Thread

      By Chuck FB · Posted

      An ultra wealthy man had the most beautiful daughter. But, there was a problem. Everything she touched would melt in her hands. No matter what, Metal, Wood, Stone. Anything she touched would melt. She could not feed herself. Because of this, men were afraid of her. Nobody would dare marry her. Her father was despaired. What could he do to help his daughter? He consulted doctors, scientists and anybody who could solve this problem. Finally one of them said, "If your daughter touches one thing that does not melt in her hands, she will be cured." He was overjoyed and came up with a plan. The next day, he held a competition. Any man who could bring his daughter an object that would not melt in her hands would be given billions of dollars to marry her. Three extremely intelligent and handsome young men took up the challenge. The first brought a very heavy steel rod, But alas, when the she touched it, it completely melted in a matter of seconds. He sadly went away. The second brought a beautiful diamond, knowing diamonds were one of the hardest substance in the world and would not melt. But alas, once she held it in her hand, it melted. He too was sent away disappointed. So now, there was one left He was very nervous & sweating. He approached the daughter & said, “put your hand in my pants pocket and feel what is in there." She did exactly what he asked. She felt something very hard. She held it in her hand, squeezing it as hard as she could. It did not melt & remained extremely hard. Her father was overjoyed. Everybody was overjoyed. She was finally cured. Nothing never, ever melted in her hand again. They married and they both lived happily ever after, raising a wonderful family. Question: What was in the the groom’s pants pocket??? Answer below ↓ M&Ms of course! They melt in your mouth, not in your hand. What on earth were you thinking?
    • asilverblazer
      Wow I'm in a pickle. (Broke down truck) and a story.

      By asilverblazer · Posted

      There's a bunch of tea leaves that you've read, but in any case the delayed timing is unusual. Not sure how that relates to the rich at idle vs. 'normal' while driving.   If you're in this deep, might be worth investigating, and re-learning the sensor. What have you got to lose? Plus, it properly fixes the timing cover leak.
    • asilverblazer
      Wow I'm in a pickle. (Broke down truck) and a story.

      By asilverblazer · Posted

      The only problem I have seen this cause is longer crank times. 
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      Injector is being sent off today for rebuild and I estimate I'll have it back in 10 days or so.   It may not be the injector...of course...now that I've torn down the intake again. But, let's rule out the injector and replace those spider legs that have been almost rubbed through.   The truck has always had negative timing and I'm reading "normal" timing at warm idle should be +16 or so. I'm negative 16 to 25 or more, and it's always been like that since I bought it.   A light turned on upstairs last night in the old noggin. Rare, I know...   This will be wild, if it turns out to be the cause!   In 2001, according to the old service documentation, the muffler was replaced. Why? I have no idea, it wouldn't have been rusted through by then. But they did a crappy job.   In 2019, another shop replaced it and noted the prior install was poorly done on the work order. "Exhaust system vibrates on crossmember". Except...I guess they just left it be? I believe the husband, the couple who were original owners, had passed by then. Maybe she said it's just not worth it to have the exhaust system fixed and declined repairs. Very few miles were driven between 2019 and 2025.   The exhaust system vibrates heavily on the crossmember and you can feel it and REALLY hear it, even today. Not always, but at idle, it gets going pretty good sometimes.   What if....   ....What if that's enough to trigger one or both of the knock sensors? Could it be tricking the sensors into sensing knock, so it's pulling timing aggressively? Pulling timing heavily means it's firing after the piston reaches full height which means incomplete burn which means the O2 sensor is sensing a rich condition, which means I've been chasing my tail, and what I thought was an inconsequential problem (janky exhaust) has been THE issue for this truck for 25 solid years?   That would be wild. Maybe it IS wild.   The service documentation thereafter, for years, shows visits for rough idle, replacing O2's, replacing the cat, replacing plugs and wires, a misfire condition, like they could never solve the issue. The injector has been replaced 4 times in 80k miles, that's just crazy.   The secondary theory....   The engine has clearly had a leak at the front seal for a very long time (the greasy trench...). I think the truck changed hands quickly ~2025 because there's Napa receipts from someone I don't recognize in the ownership history. They apparently replaced the timing cover seal, and they did a terrible job. There's RTV smeared all over and the leak I had reduced to a weep by snugging the front oil pan bolts is now a leak again.   HOWEVER....I read about replacing the crankshaft position sensor. Any time the ckp sensor is disturbed or timing cover is removed, the truck requires relearning, and that can only be done through a bi-directional scan tool. Skippy with the RTV probably didn't do the relearn procedure is my guess. His scan tool is lost in a pile of RTV goo somewhere.   So, it's very possible the sensor has been disturbed and the truck is just running on the old learn data but not setting a code for anything. The distributor has since been replaced and so has the camshaft position sensor, so all bets are off for that thing.   In the theme of one step forward, two steps back, I returned the accumulator for the AC. The gal I've been working with at O'Really's has been great. She refunded it under manufacturer's defect and we compared it to the replacement I ordered, and sure enough, the replacement is machined very differently (and a gauge actually fits on it!).   Got it home, installed it, started vacuuming it down.... and I couldn't get good vacuum.   The high side service port, where I replaced the old GM ball valve suspecting that was a source of the previous leak....well, I've clearly exposed whatever pre-existing crack in the line where the service port is welded, and made it much worse. Blessing in disguise? Except there goes another $25, now I'm waiting for a replacement AC line.   In 10-ish days ALL the parts will be here. Rebuilt injector, new exhaust system, new cat, new high pressure AC line.   Oh, did I mention the squeaking ISN'T coming from the AC pump? The truck still squeaks when started, and there were words after I started it with the new AC pump installed. But, there was more to replacing the AC pump for just a squeak. A truck with good working AC is something of value, for the comfort alone.   I've ordered a new harmonic balancer because, 30 years is a good run for one of those. Rule it out. The squeak may be something more sinister, though. I'm worried about that ckp sensor and if it was shimmed correctly, or if the timing set was installed correctly. The squeak may be coming from UNDER the timing cover.   At this point, once I get it put back together, I'm thinking I'll take a 50 mile victory lap and then promptly put it up for sale. This truck is cursed. Betty, from beyond the grave, doesn't want anyone messing with her Blazer. Or maybe she's getting revenge for 30 years of shop visits with that thing.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...