Regular or premium

not even and Shiner are both right and it’s dependent on many factors.
The beauty of modern higher performance efi engines is that most all will compensate for lower octane than recommended. To what degree is dependent on not only the engine specs and tuning but also temperature altitude and load on the engine.

To the OP, it isn’t going to blow up with one tank of low test. Try it out. Pre detonation will be obvious. Lack of performance may or may not be. Fuel mileage if tracked accurately can also be an indicator of how it performs overall with different octane.

The old saying that too much octane does no good is still true. But under load, reduced perf from too high of octane will not damage an engine but too little octane can. Generally over time and exaggerated under heavy load.

I can't speak on the new engines, but my 2011 Yukon Denali would ping if I didn't run premium.

The 6.2 LS3 on my wakeboat will run rough enough to throw a service engine code with low octane fuel (it's done it to me three times now - I hate marina fuel).

I would say that there is a reason the owners manual says to use premium.

noteven wrote:
Modern auto engines do not ping - knock detection adjusts timing and fuel to prevent any pre-ignition or detonation.

So when you buy an engine that is designed for 91 and you use 87 or less in it will run fine. It is not producing the power you paid for is all. Sometimes the vehicle will use more 87 per mile than 91, especially if you are tow / hauling and actually using max power.

Yes and no. While most modern engines can adjust to a certain octane, they can only pull so much timing and alter the cam profile to a certain degree. If the ECU pulls as much timing as it possibly can and the engine still knocks, then it is time to increase the octane. This issue is compounded with single cam pushrod engines versus overhead cam engines that have more flexibility and control of valve overlap along with ignition timing.

Modern auto engines do not ping - knock detection adjusts timing and fuel to prevent any pre-ignition or detonation.

So when you buy an engine that is designed for 91 and you use 87 or less in it will run fine. It is not producing the power you paid for is all. Sometimes the vehicle will use more 87 per mile than 91, especially if you are tow / hauling and actually using max power.

My 2012 F350 - 6.2 V8 flex fuel engine runs the same or a bit better "$/mile cost" on E0 or E10 91 pump gas than E10 87 when tow/hauling. It pulls better in the mid range running on 91. This opinion based on 4000 miles hauling a slide in camper and towing a 22 ft trailer trip in the west of Canada and USA as far south as MX.

"They" say E85 ethanol gives better performance yet.

Running around local to my summer camp not towing I run E10 87 pump gas. It has plenty of power to achieve posted speed limits hauling nothing. But it I'm going to put it to work I use 91.

Stock powertrain with 100,000 miles on it including the spark plugs.

My 2019 corvette 6.2 has premium fuel recommended. My 2019 Yukon also is recommended premium. I use regular in both and have in every car or gasoline powered truck I’ve ever owned since 1963. No ping

if the mfg recommends premium, why would you consider anything else?

I go with what the book says. My car is regular gas, Harley was premium, RZR is regular, truck is diesel.

I will say in the 2020 book it says 6.2 is premium. I have the 6.6 , and thats reguler. Its only the 6.2. Like above i had many gm trucks all were reguler. I atually called the dealership to make sure the 6.6 was regular. As the manual is a bit confusing for the 2500s.

MitchF150 wrote:
I've actually started running premium in my 13 Eco for the last 2 years now and towing my #7000 TT now compared to the old #5000 TT it makes a world of difference..

I just keep it going when not towing too.. Truck seems to really like it, especially with 93,000 miles on it now.

It's getting the best mpg's it's ever gotten not towing. Same route, driving the same way..

I towed my new #7000 TT the first time with 87 in the tank... It was a dog. Thanks to the knock sensor, it ******* the timing so much, it had no power to haul the new beast the way I was used to with the old trailer..

Remember, you just can't dump a half a tank of premium in and expect night and day results. I ran at least a full tank of premium before I towed the new trailer the second time on 92. It was a night and day difference for sure. Well for me anyway.. Your mileage may vary.

My owners manual for the Eco says it'll run fine on 87. But, if you tow heavy, they recommend running 92.

So, no idea on your 6.2.. But, I would say that if the manual recommends running "premium"... I'd go with it.. :)

Good luck! Mitch

The 3.5L is a variable fuel engine in that unlike most fixed cam/timing it can adjust timing, valve overlap, and so on to take advantage of different octane ratings. I believe it was Pickuptrucks.com who published that Ford stated that the 3.5L Ecoboost 365hp/420lb-ft on regular fuel went up to 385hp/430lb-ft on premium fuel. So unlike most engines, you are actually seeing/feeling a power increase.

I've actually started running premium in my 13 Eco for the last 2 years now and towing my #7000 TT now compared to the old #5000 TT it makes a world of difference..

I just keep it going when not towing too.. Truck seems to really like it, especially with 93,000 miles on it now.

It's getting the best mpg's it's ever gotten not towing. Same route, driving the same way..

I towed my new #7000 TT the first time with 87 in the tank... It was a dog. Thanks to the knock sensor, it ******* the timing so much, it had no power to haul the new beast the way I was used to with the old trailer..

Remember, you just can't dump a half a tank of premium in and expect night and day results. I ran at least a full tank of premium before I towed the new trailer the second time on 92. It was a night and day difference for sure. Well for me anyway.. Your mileage may vary.

My owners manual for the Eco says it'll run fine on 87. But, if you tow heavy, they recommend running 92.

So, no idea on your 6.2.. But, I would say that if the manual recommends running "premium"... I'd go with it.. :)

Good luck! Mitch