fuel type for 6.2

[kodiakdenali]

Quite second hand information, but I thought I would share

I know many members on this forum are also Corvette owners. Over on Corvetteforum I read many posts by a member who also happened to be one of the engineers who worked on the C5. which says premium recommended but the owners manual says that it will run on 87. However he says that that verbiage is misleading but due to corporate reasons, that's how it is worded. his take on it, as an engineer who knows that engine: running less than premium fuel will absolutely damage the engine over time. The way he described it was it will run on 87 or 89, and it will be ok, as long as you only run low octane in an emergency situation once in a while and get 91+ back into it as soon as possible. running a few tanks of 87 over the lifespan of the engine will not hurt it, but if you run 87 consistently it absolutely will. As I recall he described it has knock sensors which will pull timing and sacrifice power and efficiently to prevent knock, but the thing about detecting knock is knock must happens for it to be detected then dealt with. While the knock is occurring and the sensors are detecting it, bad things are happening to the engine which it can survive just fine...as long as its something that only happens rarely in the vehicle's life.

 

Now, an L87 is not an LS1, a Silverado/Sierra is not a Corvette, and the above is talking about an engine designed over 20 years ago, so who knows how similar today's situation is. even before I got supercharged I always run premium. But just saying, the C5's owners manual said similar things about running 87 in it as compared to the 6.2L, and an engineer who actually knows what he's talking about suggested that 87 was NOT ok to run habitually in that engine, only that it will survive 87 as long as it is a rare occurrence. But for whatever corporate reasons, that translates into a owner's manual saying 91+ is recommended but 87 is acceptable without qualifying properly what that means. If you want your engine to last up to the engineer's design target of a 250k mile lifespan, running 87 is not acceptable. If all you care about is the engine running fine until the power train warranty expires, then 87 is good enough.

take from that what you will.

[TNTSierra]

50 minutes ago, Robby James said:

 

I believe the term you are looking for is "penny pincher" ...lol

And the other word in the English language that you are struggling with is "Prerogative"

Where in that shrunken brain of yours did you come up with "Little Fella"?

Intelligent rapport is obviously beyond your abilities and a public forum is perhaps not the best place to display this as if you remain silent the World can question your intelligence, but when you speak (or type in this case) you expose yourself to everyone

I am certainly not in any position to pinch pennies nor will I ever be, if you actually had read my posts you could perhaps with someone explaining them to you what I was saying, The OP asked a question and I gave the correct answer to his question, your contribution to the thread was negligible at best.

Ohhh here you go this will help you out.

https://www.merriam-webster.com/dictionary/negligible

Perhaps we can get back on track now?

 

. Again if you want to belittle me because of my spelling on an iPhone, and not properly proofreading.  I can tell it obviously makes you feel better, go ahead little fella. That’s my fault for not checking over my writing first.  I’ll accept that, but getting all “butt-hurt” because I simply stated “one” shouldn’t be buying a $50k+ truck with a 6.2L (performance engine) if he/she is worried about saving $5-$10. 

Since you love to use the word “perhaps “ so much, then quite possibly you can reread my posts also! As I stated the engine “can” run on lower grade fuel but GM and the owners manual states the engine “COULD KNOCK”, so why risk damaging the engine.  Plus, I bought the performance engine for its full power and I want that full power all the time, so that’s why I choose premium. 
 

Good day!

 

[TNTSierra]

3 minutes ago, kodiakdenali said:

Quite second hand information, but I thought I would share

I know many members on this forum are also Corvette owners. Over on Corvetteforum I read many posts by a member who also happened to be one of the engineers who worked on the C5. which says premium recommended but the owners manual says that it will run on 87. However he says that that verbiage is misleading but due to corporate reasons, that's how it is worded. his take on it, as an engineer who knows that engine: running less than premium fuel will absolutely damage the engine over time. The way he described it was it will run on 87 or 89, and it will be ok, as long as you only run low octane in an emergency situation once in a while and get 91+ back into it as soon as possible. running a few tanks of 87 over the lifespan of the engine will not hurt it, but if you run 87 consistently it absolutely will. As I recall he described it has knock sensors which will pull timing and sacrifice power and efficiently to prevent knock, but the thing about detecting knock is knock must happens for it to be detected then dealt with. While the knock is occurring and the sensors are detecting it, bad things are happening to the engine which it can survive just fine...as long as its something that only happens rarely in the vehicle's life.

 

Now, an L87 is not an LS1, a Silverado/Sierra is not a Corvette, and the above is talking about an engine designed over 20 years ago, so who knows how similar today's situation is. even before I got supercharged I always run premium. But just saying, the C5's owners manual said similar things about running 87 in it as compared to the 6.2L, and an engineer who actually knows what he's talking about suggested that 87 was NOT ok to run habitually in that engine, only that it will survive 87 as long as it is a rare occurrence. But for whatever corporate reasons, that translates into a owner's manual saying 91+ is recommended but 87 is acceptable without qualifying properly what that means. If you want your engine to last up to the engineer's design target of a 250k mile lifespan, running 87 is not acceptable. If all you care about is the engine running fine until the power train warranty expires, then 87 is good enough.

take from that what you will.

Thank you!  Great response. 

[Robby James]

Thank you

Edited June 23, 2021 by Robby James
A moment of clarity

[kodiakdenali]

10 minutes ago, TNTSilverado said:

Thank you!  Great response. 

yeah, I'm not expert myself, but I see a lot of posts here by owners citing the manual indicating the designers of the engine say its ok to run 87 in it. But its possible that is not what the manual is saying...not really, so says a GM engineer.

87 being perfectly fine for a high compression performance oriented engine might be what the engineers "said" after edits by a few bean counters and corporate politicians, or maybe powertrain technology has just come to the point where it actually is ok and won't affect longevity. I can't say. It's up to the owner to decide.

[Robby James]

21 minutes ago, kodiakdenali said:

Quite second hand information, but I thought I would share

I know many members on this forum are also Corvette owners. Over on Corvetteforum I read many posts by a member who also happened to be one of the engineers who worked on the C5. which says premium recommended but the owners manual says that it will run on 87. However he says that that verbiage is misleading but due to corporate reasons, that's how it is worded. his take on it, as an engineer who knows that engine: running less than premium fuel will absolutely damage the engine over time. The way he described it was it will run on 87 or 89, and it will be ok, as long as you only run low octane in an emergency situation once in a while and get 91+ back into it as soon as possible. running a few tanks of 87 over the lifespan of the engine will not hurt it, but if you run 87 consistently it absolutely will. As I recall he described it has knock sensors which will pull timing and sacrifice power and efficiently to prevent knock, but the thing about detecting knock is knock must happens for it to be detected then dealt with. While the knock is occurring and the sensors are detecting it, bad things are happening to the engine which it can survive just fine...as long as its something that only happens rarely in the vehicle's life.

 

Now, an L87 is not an LS1, a Silverado/Sierra is not a Corvette, and the above is talking about an engine designed over 20 years ago, so who knows how similar today's situation is. even before I got supercharged I always run premium. But just saying, the C5's owners manual said similar things about running 87 in it as compared to the 6.2L, and an engineer who actually knows what he's talking about suggested that 87 was NOT ok to run habitually in that engine, only that it will survive 87 as long as it is a rare occurrence. But for whatever corporate reasons, that translates into a owner's manual saying 91+ is recommended but 87 is acceptable without qualifying properly what that means. If you want your engine to last up to the engineer's design target of a 250k mile lifespan, running 87 is not acceptable. If all you care about is the engine running fine until the power train warranty expires, then 87 is good enough.

take from that what you will.

An intelligent response, how welcome it is.

[OnTheReel]

These are things as I understand them. I didn’t wanna get in the weeds. And I am not a tuner but I’ve dabbled a bit. 
 

You’re always going to see a little KR from time to time, even on 93. The ECM wants a certain number of degrees advance. But load, humidity, ambient temp, fuel quality will all vary, and sometimes it needs to pull back from it’s target. This happens well before any audible pinging or damage can occur. And there is a decay algorithm programmed in that will reattempt to hit the maximum timing after a short period of time. Basically it’ll continue to test the limit. So with that in mind, if you AREN’T running into KR once in awhile, you’re probably leaving power on the table. 
 

On the flip side, if you are driving around with 8 degrees of timing pulled all day because you saved 20 cents a gallon on 87, you are also leaving a lot of power on the table. Is that alone going to kill it? No. The ECM is only going to pull so much timing and not enough to harm it. 

 

But I think the reference about audible pinging in the owners manual implies that there are possible situations where the ECM cannot compensate for your pennywise fuel choice. Hot day, pulling a trailer, bad gas, any number of things. And then you might be risking screwing something up. 

 

But my main argument is not that you might blow it up, it’s that you should get the power you paid for.

[Rob Mugs]

2 hours ago, Robby James said:

Again, never stated I was worried about saving any pesos little sister as I am not and I never got butt hurt as I shall leave that area up to you as it seems your arena I simply answered the OP's question.

I just would like to point out the irony of you pointing out someone else's grammar with a hot mess like this 

PS, your answer was, for all intents and purposes, WRONG

Edited June 18, 2021 by Rob Mugs

[TNTSierra]

My response was very intelligent. It made perfect sense, but so many people

in this world have “WANTS” over “NEEDS” and get themselves in a bind when they buy things.  “Oh, I can afford this payment but the gas…….oh NO”!!!!   I see it daily in my profession 

 U just went off on a “hooked on phonics” rant and how people should tell you to buy things. I never stated any of that. Anyways, I don’t have to go back and forth with a penny pincher, “macho ego” man child on this forum.  Go save your money and buy what you want. I’ll follow the manual and love all the true HP the premium gas gives me. Psst, just because I WANT all 420+HP because that’s what I CHOOSE to have when I bought the truck.  I won’t go and try to “demean” your other half like you. I don’t stoop that low. If u came around my neck of the woods, you might find yourself with a black eye, and a “knocking” headache kinda like your engine would be running 87 all the time. 
 

good day to you SIR!!!

 

[Grumpy Bear]

3 hours ago, kodiakdenali said:

As I recall he described it has knock sensors which will pull timing and sacrifice power and efficiently to prevent knock, but the thing about detecting knock is knock must happens for it to be detected then dealt with. While the knock is occurring and the sensors are detecting it, bad things are happening to the engine which it can survive just fine...as long as its something that only happens rarely in the vehicle's life.

 

Incipient Detonation is of little concern. Even the lowly 4.3 is pulling timing on a regular basis. Every meaningful rise in elevation. While it is true the sensor has to 'hear' knock to adjust for it it is also true it 'hears' so well that the level present is of no clear present danger. They use the sensor as by the time it is audible to a human it is destructive. An air cooled HD TC88 will teach  you the difference pretty quick. 

 

I would expect that this guy means 'audible' detonation as it is not something displayed nor heard and yet occurs all the time. The owner operator would never know it was happening without monitoring the sensor. 

 

Pepper is an 87/FF vehicle and yet will show KI ****** (Scan Gauge monitor) on 93 and even E-85 if levels of alcohol are less than 70%. I've seen up to 7.5* of KI and never EVER hear it in the cabin. 

 

To maximize economy the ECU is always 'testing' the limit of knock driving timing until it does the backing out. Rinse and repeat many times a second. 

 

If you have 3 cents and my contribution you now have a nickel.  

Edited June 18, 2021 by Grumpy Bear

[JimCost2014]

Sorry, just could not resist. 

 

[tboat]

On 6/13/2021 at 6:33 PM, tboat said:

Just took delivery on a 2021 Sierra Denali with the 6.2.  Flipping through the owners manual I found it's recommended to use the 93 octane premium fuel.  What's everybody using and have you noticed any mileage drop or pinging using lower octane fuel?

Well.......that simple question certainly got out of hand.  After reviewing all of the responses, I have decided to use the 93 octane.  Thanks for all the input.

[Robby James]

I just filled her to the brim with Premium and even spilled a bit on the ground just because I can afford it and to honor the great keyboard warriors out there, they know who they are  LMAO

[KARNUT]

29 minutes ago, Robby James said:

I just filled her to the brim with Premium and even spilled a bit on the ground just because I can afford it and to honor the great keyboard warriors out there, they know who they are  LMAO

I know you’re just being funny….. I guess. You go past the first click ( shut off) of the pump. Damage will result. You may know that. Just thought I’d mention, just in case.

[KARNUT]

There’s some vehicles, started with the mustang. The first one I remember. That gave you a choice regular or premium gas. Premium providing more horsepower. No damage using one or the other. I guess GM hasn’t figured out how to do that yet. Of course I did have a GM the would give more horsepower on E-85. So it boggles the mind that you couldn’t run reg gas in the 6.2. I wonder. The mustang was a turbo 4. It was pretty slick.