6.2 Engine: To Premium Or Not, Facts Here

BringTheRain403 · August 28, 2019

For an extra $4 per week I'll run premium...

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truck_newbie · August 29, 2019

47 minutes ago, gone_fishing said:

Do you know if the premium fuel was ethanol free? In my area, premium (91 octane) gas is available with ethanol (E10) or without (E0). Just depends on the station. E10 91 octane is generally less expensive then E0. Seems like E0 will usually gain you a little fuel economy. I believe that is because it has more energy (BTU's). Adding ethanol reduces it's energy content but is also cheaper. Hard to say if it pencils out.

I'm far from a tuning expert but do monitor timing advance and knock retard with a ScanGauge device. From what I have learned watching these numbers is the computer always seems to want to maximize timing advance as much as possible. If it picks up a few degrees of KR, it backs off timing advance (as it should). From a fuel economy stand point, I imagine the engine is more efficient when the timing is advanced? Even when cruising with a light load (flat road, no wind, not towing) a slight increase in load (incline of a bridge or overpass) can sometimes cause a little KR. Seems like the computer is always trying to push the limit a little. Read somewhere that is does "learn" where it can operate. I wonder if a 6.2 can "learn" to run on 87?

I only fill-up at Shell. In my neck of the woods, they have a sticker that says can contain up to 10% ethanol. I don't know if that also applies to the v-power/premium.

Your analysis on timing is what EE in the video explains. An engine that lists recommended is designed to adapt. It will try to advance timing as much as possible because that's what gives the best fuel economy and power. Based on the results in the study, it seems the L86/L87 engine has been tuned to advance timing for fuel economy only. If you switch to regular, it will retard timing and use more fuel but give you the same power. An engine that requires premium will not retard timing by much if at all. That's why the Audi in the study was knocking because it required premium.

truck_newbie · August 29, 2019

4 hours ago, aseibel said:

I don't know why anyone would choose to pay extra for a 6.2 and then put 87 in it. There are plenty of 5.3's available for the cost conscious consumer.

But if you do have a 6.2 and are more concerned with cost of fuel/mile, you are not coming out ahead by paying for 93 octane. Any small gains do not offset the extra cost.

Just like anyone with a 5.3 who buys premium fuel won't notice any benefits either.

Put in the gas you want, its your truck.

I don't understand your reasoning. People are of course free to put whatever fuel they want in their engine. I see this less of cheaping out on premium fuel and more of what you gain or lose by going regular. This study has proved, and backed it up with scientific data that you don't gain anything by running premium (adjusting for the mpg gain of premium) on the 6.2.

Personally, if i pay for something, i want to be sure i'm getting the benefits. I paid extra for the 6.2 engine because i know i'm getting significant extra hp and torque over the 5.3. Based on this study, I've come to the realization that i'm not gaining anything by fueling the 6.2 with premium.

truck_newbie · August 29, 2019

2 hours ago, Joe98 said:

I second this... thanks.

You are both welcome.

Hydro4acid · August 29, 2019

Can we assume that both previous generation 6.2L and this generation 6.2L will both have the same response to 87 octane vs 91/93?

Ethanol will obviously provide a mpg hit, but if its cheaper without power loss...why not.

BringTheRain403 · August 29, 2019

Ethanol would be better than premium and jump the HP by a bit too. It's a higher octane. The new motors aren't flex fuel tough and running ethanol would cause a CEL to come on...

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aseibel · August 29, 2019

10 hours ago, truck_newbie said:

I don't understand your reasoning. People are of course free to put whatever fuel they want in their engine. I see this less of cheaping out on premium fuel and more of what you gain or lose by going regular. This study has proved, and backed it up with scientific data that you don't gain anything by running premium (adjusting for the mpg gain of premium) on the 6.2.

Personally, if i pay for something, i want to be sure i'm getting the benefits. I paid extra for the 6.2 engine because i know i'm getting significant extra hp and torque over the 5.3. Based on this study, I've come to the realization that i'm not gaining anything by fueling the 6.2 with premium.

I'm just saying, why pay more for a truck with a 6.2, only to put regular gas in it? Did you really need the 6.2 then? If you want to take advantage of every horse under the hood, you pay for premium fuel. If you don't need those few extra horses, then a 5.3 would suit you just fine.

BringTheRain403 · August 29, 2019

If you can afford a $60k+ truck you can afford an extra $6-$8 per fill-up to put the recommended fuel in it. If your budget is that tight then maybe you shouldn't be buying that truck. Just sayin...

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UncleDave · August 29, 2019

In my neck of the woods, we don't have 91 everywhere, but we do have 93. The 93 is on average $0.30/gal more than 87. That's roughly $7 more per fill from almost empty. If I fill once per week that's an extra $364/year, or $30.33/month. If you can afford an extra $30/mo, then it's worth it to fill with premium exclusively and enjoy the benefits thereof. JM2C.

truck_newbie · August 29, 2019

58 minutes ago, aseibel said:

I'm just saying, why pay more for a truck with a 6.2, only to put regular gas in it? Did you really need the 6.2 then? If you want to take advantage of every horse under the hood, you pay for premium fuel. If you don't need those few extra horses, then a 5.3 would suit you just fine.

That's a blanket statement and generally i would agree with you if there wasn't any data. Fortunately, there is data. Did you even look at the actual report with the numbers and horsepower/torque charts? I'll summarize below.

5.3 Engine
-----------------
Power = 355 hp; Torque = 383 lb-ft

6.2 Engine
------------------
Power (Premium) = 420 hp; Torque (Premium) = 460 lb-ft
Power (Reg) = 417 hp; Torque (Reg) = 460 lb-ft

I will still be very happy with the 62 hp i'm gaining over the 5.3 compared to the 65 hp i could be getting. I'm sure that 3 hp delta makes all the difference in a 5500 lb truck. Sorry to be sarcastic, just couldn't help it.

aseibel · August 29, 2019

13 minutes ago, truck_newbie said:

That's a blanket statement and generally i would agree with you if there wasn't any data. Fortunately, there is data. Did you even look at the actual report with the numbers and horsepower/torque charts? I'll summarize below.

5.3 Engine
-----------------
Power = 355 hp; Torque = 383 lb-ft

6.2 Engine
------------------
Power (Premium) = 420 hp; Torque (Premium) = 460 lb-ft
Power (Reg) = 417 hp; Torque (Reg) = 460 lb-ft

I will still be very happy with the 62 hp i'm gaining over the 5.3 compared to the 65 hp i could be getting. I'm sure that 3 hp delta makes all the difference in a 5500 lb truck. Sorry to be sarcastic, just couldn't help it.

No problem. I agree with you. Just be careful posting facts on the internet. The die hard 6.2 crowd will crucify you. Some people don't understand the difference between "recommended" and "required".

Snakes709 · August 29, 2019

39 minutes ago, aseibel said:

No problem. I agree with you. Just be careful posting facts on the internet. The die hard 6.2 crowd will crucify you. Some people don't understand the difference between "recommended" and "required".

My wife was like that. Says to use 91 octane on the gas tank door of her chevy equinox. But in the manual it says 91 is recommended but 87 is acceptable and the ecu will adapt to the octane change. I took the suv across canada/northern states and didnt notice a few gas stations in the states the pumps are 93, 89 amd 87 left to right where its 87, 89 and 91 here. So i accidentally filled up with 93 and holy **** what a difference in that little 2.0 turbo.

Barely felt a difference, if any, on my 6.2 when i put in 91 after the dealership put in 87. Maybe a little better throttle response but no power or mpg increase.

truck_newbie · August 29, 2019

48 minutes ago, aseibel said:

No problem. I agree with you. Just be careful posting facts on the internet. The die hard 6.2 crowd will crucify you. Some people don't understand the difference between "recommended" and "required".

Your reply made creating this thread worth it.

I really like the saying by Daniel Patrick Moynihan:

"Everyone is entitled to his own opinion, but not his own facts."

Roscopcoletrain · August 29, 2019

curious why some 6.2s knock/ping on 87 vs others

amxguy1970 · August 29, 2019

54 minutes ago, Roscopcoletrain said:

curious why some 6.2s knock/ping on 87 vs others

Placebo effect, they want to hear/feel it (yet most don't know what they are listening/feeling for). I bet they want to feel like they own a motor that only runs on premium like a sports car... If you hear/feel it the truck pulls timing and it goes away and doesn't hurt anything. With modern cars they can detect the smallest of knocks/pings and fix it before it is even noticed by the driver in most cases.

Tyler