6.2L Engine... What gas are you using?

[Monkey01]

Hi,

Just curious if anyone has been using regular gas 87 on their 6.2L V8? If so, how has the engine been so far. Any feedback is well appreciated.

I travel alot and with constant increase in price its getting very expensive. Does regular gas hurts the engine. (I understand performance and gas mileage do hurt alittle. Thanks

 

[Micahsd]

Back when I had a 2007 Corvette with the 6.0L V8 that required premium, I'd occasionally run 87 in it and had no issues other than maybe a little more knocking.

I've got the 5.3L in my '21 Tahoe which is mostly why I went that route due to how it didn't require premium. The 6.2L would be nice though (just not at the pump).

What's driving me nuts is gas milage...I knew it wouldn't be great, but when the gas prices increase I tend to cringe as I'm getting about 12-13 MPH in town (which is probably due to a lot of idling and short trips). One of my friends has a 10-year old Honda which gets 30.5 MPH in town...not jealous of the Honda, but I'm for sure jealous of the gas mileage.

 

[mikeyss]

I use E85 in my 6.2, but I have an L9H flex fuel

 

[Seamus]

Octane rating needed is only to prevent knocking. So if you put 92 in a truck that only needs 87 to prevent knocking your wasting your money. The issue with modern cars is they have knock sensors. When your truck starts to knock it retards the timing to stop the knocking as it is very harmful to your engine. That also loses power. So your truck runs correctly and optimally with 92 octane. Its tuned for it. It is the most efficient with it. When you put a lower octane in it....you may not realize it due to the knock sensors, but its knocking....so your computer will adjust the tuning to try to prevent the knocking. It can only do it to a certain point. Knocking is detonation. That is an engine killer. Can you get away with a trip on 87 no load, not towing, no high heat.??...yes. Its not good to do. In the old days when we did this on a non computer vehicle you heard quite alot of knocking...which is damage. Your truck is designed and tuned for ONLY 92.

On a side note I feel your pain. I had a 2017 Denali, but the older generation got pretty good mileage. I routinely got 22-23 hwy. It was unforgiving if you floored it though. We went to buy a 2021 Denali, did the test drive, loved it. I was really surprised the mileage went down. Then spoke and read up that it was even worse than that. ??? I dont know what GM did, but it was a deal breaker for me. Then the lifter issue arose. We rented a '21 suburban for a month and the mileage was very good in the 5.3. I just dont want a 5.3 at that price point. The 3.0 was what I needed for towing and normal mileage. Early on they werent around yet, so we bought the Denali CC with 3.0. its our in-between truck till this insanity stops. Mileage is insane, torque is fantastic, tows great. So our next Yukon Denali will have the 3.0. Loved the speed and power of the 6.2 but todays version has unacceptable mileage. Hopefully prices come down, but I would run 92 if i owned it. Good luck

 

[Monkey01]

Octane rating needed is only to prevent knocking. So if you put 92 in a truck that only needs 87 to prevent knocking your wasting your money. The issue with modern cars is they have knock sensors. When your truck starts to knock it retards the timing to stop the knocking as it is very harmful to your engine. That also loses power. So your truck runs correctly and optimally with 92 octane. Its tuned for it. It is the most efficient with it. When you put a lower octane in it....you may not realize it due to the knock sensors, but its knocking....so your computer will adjust the tuning to try to prevent the knocking. It can only do it to a certain point. Knocking is detonation. That is an engine killer. Can you get away with a trip on 87 no load, not towing, no high heat.??...yes. Its not good to do. In the old days when we did this on a non computer vehicle you heard quite alot of knocking...which is damage. Your truck is designed and tuned for ONLY 92.

On a side note I feel your pain. I had a 2017 Denali, but the older generation got pretty good mileage. I routinely got 22-23 hwy. It was unforgiving if you floored it though. We went to buy a 2021 Denali, did the test drive, loved it. I was really surprised the mileage went down. Then spoke and read up that it was even worse than that. ??? I dont know what GM did, but it was a deal breaker for me. Then the lifter issue arose. We rented a '21 suburban for a month and the mileage was very good in the 5.3. I just dont want a 5.3 at that price point. The 3.0 was what I needed for towing and normal mileage. Early on they werent around yet, so we bought the Denali CC with 3.0. its our in-between truck till this insanity stops. Mileage is insane, torque is fantastic, tows great. So our next Yukon Denali will have the 3.0. Loved the speed and power of the 6.2 but todays version has unacceptable mileage. Hopefully prices come down, but I would run 92 if i owned it. Good luck

Thank you for this info. Don't want to hurt the engine... That's the answer.

 

[Stbentoak]

This horse has been pretty well beat to death. What does anyone expect driving a large V8 moving the equivalent of a short bus around town? Gas is not going down, and very well may go WAY up with this Ukraine issue. When you drive these big vehicles you better very well need them and their utility. They are neither cheap to own or operate. If you are even worried about these issues or expense of owning, Buy something smaller and more efficient. You can't buy a Great Dane and then expect it to live on 6 0z cans of cat food....

 

[VAguy68]

I thought about this a lot before I bought my 5.3 Z71. You CAN run the 6.2 on 87 and the computer will adjust timing to protect the engine but it's not optimal to run at peak efficiency. I'm happy with the 5.3 and it moves me down the road just fine. I've got 38K on it already and for the life of the vehicle I have an overall average close to 19. I think that's reasonable for such a large vehicle. Now I have a Corvette Z06 if I feel the need for speed. I also have a beater 06 Honda Civic that I plan to start driving more as fuel prices start to skyrocket.

 

[Monkey01]

I thought about this a lot before I bought my 5.3 Z71. You CAN run the 6.2 on 87 and the computer will adjust timing to protect the engine but it's not optimal to run at peak efficiency. I'm happy with the 5.3 and it moves me down the road just fine. I've got 38K on it already and for the life of the vehicle I have an overall average close to 19. I think that's reasonable for such a large vehicle. Now I have a Corvette Z06 if I feel the need for speed. I also have a beater 06 Honda Civic that I plan to start driving more as fuel prices start to skyrocket.

Thank you. My main concern was about degrading the engine and if there is a chance of 87 octane damaging the engine, then I will only use premium. I didnt know if the premium gas was only for better performance and efficiency. With that said, when power is needed time to time, it's nice to have that extra power for passing and towing.

 

[swathdiver]

Hi,

Just curious if anyone has been using regular gas 87 on their 6.2L V8? If so, how has the engine been so far. Any feedback is well appreciated.

I travel alot and with constant increase in price its getting very expensive. Does regular gas hurts the engine. (I understand performance and gas mileage do hurt alittle. Thanks

Running 87 does damage to the engine over time with regards to the 6.2. We see lots of broken rings and pistons on these forums because of it after many years of abuse.

 

[Joseph Garcia]

I use only 93 octane in my 6.2. But my truck is specifically tuned to use 93 octane.

 

[Blackhawkscrna]

I’ve had a 6.2 in 3 Yukon Denali since 2007. Always used 93, 0 engine problems. That being said, I have a z71 with 5.3 on order , and one reason is I’m tired of spending the extra on premium.

 

[Monkey01]

Running 87 does damage to the engine over time with regards to the 6.2. We see lots of broken rings and pistons on these forums because of it after many years of abuse.

Thank you. Premium it is.

 

[Geotrash]

While the ECM is designed to protect the engine when run on low octane fuel, it's not a perfect system and there is only so much it can do. We now have 15 years of experience on here with people running the 6.2 and have hashed this out in the other gen. forums several times. Several people have run their engines instrumented to compare timing and pre-ignition events (which are mostly inaudible on these) and the data is compelling on 87 vs 93. That, taken with the evidence that piston failure due to damage commensurate with running them on 87 is a common failure point, and the evidence is clear: The 6.2 will have problems over time if they are run on 87. You'll get away with it for a while, but engine longevity will be affected - especially under high load situations.

Nice summary of a 6.2 failure here from a guy who tears down a lot of engines. Link goes to the correct starting point to save you time.

 

[Monkey01]

While the ECM is designed to protect the engine when run on low octane fuel, it's not a perfect system and there is only so much it can do. We now have 15 years of experience on here with people running the 6.2 and have hashed this out in the other gen. forums several times. Several people have run their engines instrumented to compare timing and pre-ignition events (which are mostly inaudible on these) and the data is compelling on 87 vs 93. That, taken with the evidence that piston failure due to damage commensurate with running them on 87 is a common failure point, and the evidence is clear: The 6.2 will have problems over time if they are run on 87. You'll get away with it for a while, but engine longevity will be affected - especially under high load situations.

Nice summary of a 6.2 failure here from a guy who tears down a lot of engines. Link goes to the correct starting point to save you time.

Thank you. Very informative.

 

[WalleyeMikeIII]

My 2022 Yukon Owners manual says 91 is the recommended. I looked at the 2021 manual online and compared. 2021 recommended 93 They did change it to 91 this year. Not sure if there was a change to the engine tune, or just “marketing.” I was pleased with this because finding 93 in MN is difficult. 91 is available as the “premium” everywhere in the state. Our Costco has 92…and it’s about $0.60 less than the 91 everywhere else…I’m only on my 2nd tank, but it’s been Costco for me.

 

[Fless]

While the ECM is designed to protect the engine when run on low octane fuel, it's not a perfect system and there is only so much it can do. We now have 15 years of experience on here with people running the 6.2 and have hashed this out in the other gen. forums several times. Several people have run their engines instrumented to compare timing and pre-ignition events (which are mostly inaudible on these) and the data is compelling on 87 vs 93. That, taken with the evidence that piston failure due to damage commensurate with running them on 87 is a common failure point, and the evidence is clear: The 6.2 will have problems over time if they are run on 87. You'll get away with it for a while, but engine longevity will be affected - especially under high load situations.

Nice summary of a 6.2 failure here from a guy who tears down a lot of engines. Link goes to the correct starting point to save you time.

He tears down a variety of engines, and I find his videos interesting and informative. Along with some subtle humor/sarcasm.

 

[Stbentoak]

My 2022 Yukon Owners manual says 91 is the recommended. I looked at the 2021 manual online and compared. 2021 recommended 93 They did change it to 91 this year. Not sure if there was a change to the engine tune, or just “marketing.” I was pleased with this because finding 93 in MN is difficult. 91 is available as the “premium” everywhere in the state. Our Costco has 92…and it’s about $0.60 less than the 91 everywhere else…I’m only on my 2nd tank, but it’s been Costco for me.

If you are lucky enough to have a Costco or Sam's club with fuel near you, this is a No Brainer really. Their Premium is equal or less price than RUL at normal stations around us. Ya, you may have to wait a little bit, but saving 8-10.00 a fill-up is well worth it. I wish they sold diesel....

 

[WalleyeMikeIII]

What's everyone's thoughts on the switch from 93 --> 91 in the owners manual...do you think they made any engine tune changes, or just did this for Marketing?

 

[Geotrash]

What's everyone's thoughts on the switch from 93 --> 91 in the owners manual...do you think they made any engine tune changes, or just did this for Marketing?

It's likely just a correction. The manual should have stated 91 from the beginning because as previously mentioned, 91 is the highest you can get in the mountain states. 93 isn't sold there because it isn't needed at higher elevation. Normally aspirated engines lose about 3% of their horsepower for every 1000' above sea level due to thinner air. Thinner air = less compression, less compression = less pre-ignition potential so 91 prevents it there as well as 93 does at lower elevation. I would still run only 93 at lower elevations.

 

[WalleyeMikeIII]

It's likely just a correction. The manual should have stated 91 from the beginning because as previously mentioned, 91 is the highest you can get in the mountain states. 93 isn't sold there because it isn't needed at higher elevation. Normally aspirated engines lose about 3% of their horsepower for every 1000' above sea level due to thinner air. Thinner air = less compression, less compression = less pre-ignition potential so 91 prevents it there as well as 93 does at lower elevation. I would still run only 93 at lower elevations.

Fair enough, Minnesota is only 800-1100' above sea level, but the state mandated "premium" is min 91, which is what is mostly available...there are a few 93's around...but not many. Costco is 92. Net, do I run 91, 92, or 93 (priority being engine longevity) or should I imagine that any of these is ok?