6.2L gas 91 vs 93

Hydro4acid · August 6, 2019

Hey guys. Getting close to getting my truck, but was reading the truck manual and it says you're recommended to run 93 octane.

That's pretty hard to find around my area in Alberta other than husky and petro-can which I don't have by my house.

Would 91 from shell be okay? What are you guys using? Am I gonna be knocking the engine with 91?

What are your experiences with 91/93 octane?

If people are having bad experiences with 91 octane and need 93 I might have to rethink my truck...

Thanks

bshort · August 6, 2019

I run 91. No issue.

Sierra Dan · August 6, 2019

93 is recommended. Not "required"

There are some threads over on the 2014-2019LD K2 platform that discuss which octane to run in the 6.2

Z45 · August 6, 2019

I been using 91 for years (first 6.2L was a '12 Denali), 93 is non-existent around here so no choice. Most use Shell or Murphy, closest.

Edited August 6, 2019 by elcamino

Roscopcoletrain · August 6, 2019

yeah, 91 is considered premium here.

killramos · August 6, 2019

45 minutes ago, Hydro4acid said:

Hey guys. Getting close to getting my truck, but was reading the truck manual and it says you're recommended to run 93 octane.

That's pretty hard to find around my area in Alberta other than husky and petro-can which I don't have by my house.

Would 91 from shell be okay? What are you guys using? Am I gonna be knocking the engine with 91?

What are your experiences with 91/93 octane?

If people are having bad experiences with 91 octane and need 93 I might have to rethink my truck...

Thanks

I had the same debate in another gas thread last week. My preference is also Shell to avoid ethanol and don’t want to run Petro or Husky exclusively. In you are in BC Chevron has 94 octane ethanol free which is awesome, not sure if the new chevron they opened in Cochrane has this or not.

But mostly you will just get guys on here telling you to run 87 because Premium dundonuffin according to their but dyno.

Overall at Alberta’s altitude especially in the mountains 91 is probably fine due to the thinner air, knocking is much more prevalent at near sea level and one of the reasons we don’t see many stations with over 91 here. That being said I wish I could take a GM engineer out for a beer to have this discussion with someone who actually knows what they are talking about from an engineering standpoint and how these engines actually react.

Grumpy Bear · August 6, 2019

I'm disappointed....again. Google octane v elevation and get a million pages of opinions and not a single fact. You use to be able to get REAL information on the net.....

Okay the hard way then. Wallace Racing has a cranking compression calculator. Plug in you particulars and bingo you pressures displayed so easy a caveman can do it. Next visit:

https://www.mide.com/pages/air-pressure-at-altitude-calculator

Use the information their to correct your first and you will find that 6,000 feet of elevation takes away 20% of your cranking pressure thus 20% of your BMEP which is directly relatable to your octane requirements.

Or the easy way....visit Colorado's Denver and note that it would appear that 5,000 feet = 2 points of octane.

OR easier yet use 91 and let your trucks ECU do it's job.

amxguy1970 · August 6, 2019

87 is fine so 91 is fine. 93 to 87 you can expect to lose about 15 ish hp and half an mpg. Use what you feel comfortable doing, to get the full monty of the engine run 93 otherwise anything less you get 97%... Are you going to feel the difference in 3%?

https://www.caranddriver.com/reviews/comparison-feature/a28565486/honda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/

Tyler

Cpl_Punishment · August 6, 2019

I prefer Esso/Mobil 91 octane. No ethanol like Petro-Can and no nitrogen like Shell.

ATC 250R · August 7, 2019

https://www.nytimes.com/2016/09/23/automobiles/dont-waste-money-on-premium-gas-if-your-car-is-made-for-regular.html

"And at General Motors, premium gas is required only in vehicles like the Chevrolet Camaro ZL1 and the Corvette Z06, with their supercharged 6.2-liter V8 engines. Even the big Cadillac Escalade recommends, but does not require, premium fuel.

In fact, more than 90 percent of the company’s products are calibrated for regular gasoline, according to Bill Studzinski, G.M.’s engineering group manager for fuels. “We have always said, ‘Don’t put more octane in your tank than the owner’s manual requires,’” he said.

Ford and G.M. agreed that there was one exception: If a vehicle was used to pull a heavy load or operate in extremely dry conditions, “you might gain a little in performance” from premium, Mr. Studzinski said. “Generally, there’s not a big benefit.”

fredcase · August 7, 2019

I'm surprised 93 is recommended in a N/A motor. What is this motors compression ratio? if under 10.5:1 I'm sure 87 is fine.

As for Alberta gas, i'm pretty experienced on it, my turbo car hates our gas and altitude.

husky 94=highest octane

Petro 94=decent octane, winter formula is garbage

shell 91= lower octane, but zero ethanol=better mpg's

Costco Premium is the same as shell 91, just a little cheaper.

esso+mobile=the worst. low octane, and high ethanol last I checked.

They opened a Chevron here in Edmonton, it doesn't have 94 yet, but, they claim it will, but I have not read great things about Chevron 94 octane quality.

BlancoSilverado · August 7, 2019

Ok, from what i know,

Some states have the gas stations show the nominal octane rating and some states show their maximum octane rating. So it really matters on what state that you are in.

In Michigan they have 87,89,93 octane (from 2 gas stations i found googling). So it seems that they state the maximum octane instead of nominal(googling).

If anyone that lives in Michigan please chime in and let us know what they see on the pump.

Edited August 7, 2019 by BlancoSilverado

fredcase · August 7, 2019

PON in North America is R+M/2

PON=posted octane number

R=Research Octane

M=Motor Octane

i just googled it, compression is 11.5:1 on the 6.2L, so, some decent octane is required.

Edited August 7, 2019 by fredcase

HondaHawkGT · August 7, 2019

On 8/6/2019 at 8:28 AM, killramos said:

I had the same debate in another gas thread last week. My preference is also Shell to avoid ethanol and don’t want to run Petro or Husky exclusively. In you are in BC Chevron has 94 octane ethanol free which is awesome, not sure if the new chevron they opened in Cochrane has this or not.

But mostly you will just get guys on here telling you to run 87 because Premium dundonuffin according to their but dyno.

Overall at Alberta’s altitude especially in the mountains 91 is probably fine due to the thinner air, knocking is much more prevalent at near sea level and one of the reasons we don’t see many stations with over 91 here. That being said I wish I could take a GM engineer out for a beer to have this discussion with someone who actually knows what they are talking about from an engineering standpoint and how these engines actually react.

Nearly every modern engine is designed to take advantage of as much spark timing and valve timing as it can, even when 87 is all that's required. The more they can push the engine to maximize performance on the fuel it's using, whether it's 87 octane or 94 octane, the more fuel efficient the engine will be. They're all tuned to bounce off of the knock sensors. Ford actually says "Do not be concerned if the engine sometimes knocks lightly. However, if the engine knocks heavily while using fuel with the recommended octane rating (91+), contact an authorized dealer to prevent any engine damage."

In addition to pulling spark timing, the engine has variable valve timing which can actuate the cam and change valve timing to reduce dynamic compression depending on load and RPM. Even though the engine has a static compression of 11.5:1 (actual compression ratio will always be less than 11.5:1), the ECU can adjust valve timing to control how much air is actually getting pulled into the combustion chamber, which affects actual dynamic compression. Direct injection adds more safety factor to running on lower octane gasoline.

Valve timing (along with DI) is a big reason for how Ford is building 5.0 Coyotes with 12:1 compression that only require 87 octane (91+ recommended in the Mustang GT's) and why their twin turbo Ecoboost engines only require 87 (91+ recommended when towing). The H.O. 3.5 Ecoboost in the Raptor has 10:1 compression and max stock boost is somewhere around 18 PSI, yet Ford still says only 87 required but premium fuel recommended.

Cpl_Punishment · August 7, 2019

3 hours ago, fredcase said:

I'm surprised 93 is recommended in a N/A motor. What is this motors compression ratio? if under 10.5:1 I'm sure 87 is fine.

As for Alberta gas, i'm pretty experienced on it, my turbo car hates our gas and altitude.

husky 94=highest octane

Petro 94=decent octane, winter formula is garbage

shell 91= lower octane, but zero ethanol=better mpg's

Costco Premium is the same as shell 91, just a little cheaper.

esso+mobile=the worst. low octane, and high ethanol last I checked.

They opened a Chevron here in Edmonton, it doesn't have 94 yet, but, they claim it will, but I have not read great things about Chevron 94 octane quality.

False. Esso and Mobil have no ethanol in their 91.

You realise that 94 and 91 are the octane ratings, right? Ok, technically they're the AKI, which is the average of RON and MON. But given that it's all government mandated, to say one has higher or lower octane makes no sense.