Owners manual recommends 93 octane

[Chevyguy273]

New owner of a 2020 Silverado 1500 Crew Cab short box LTZ with the 6.2l here. Is it ok to use 91 octane? Because in my local area. Out of like 20-30 gas stations within our like 5 town/city metro area. There is only 1 station that sells 93. I was stunned reading the owners manual and seeing that in the fuel use section. I’m pretty sure these 6.2l run fine on 91 octane. Please correct me if I’m wrong. Thank you. 

[diyer2]

Try a search.

found this 

 

[2018GMC]

Octane offerings are based on altitude. In high elevation areas only 91 is offered.

https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1601859

https://www.vroomgirls.com/all-about-octane/

Your 6.2l truck will be just fine on 91 octane.

[Chevyguy273]

44 minutes ago, 2018GMC said:

Octane offerings are based on altitude. In high elevation areas only 91 is offered.

https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1601859

https://www.vroomgirls.com/all-about-octane/

Your 6.2l truck will be just fine on 91 octane.

Thank you. I actually was a little miffed at why the manual says 93 but just about every thing I have read about 91 octane has been positive. So 91 it is. 

[eppieguy]

Yes 

[AlaskaErik]

3 hours ago, 2018GMC said:

Octane offerings are based on altitude. In high elevation areas only 91 is offered.

https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1601859

https://www.vroomgirls.com/all-about-octane/

Your 6.2l truck will be just fine on 91 octane.

I live at sea level and all our premium fuel is 90 octane.  You literally cannot get anything in a higher octane.  Every pump is 87, 89 and 90.

[mike5511]

I forget what year they redid the octane thing. Ours used to be 93 here, then it dropped to 91. New standards took over I guess. Maybe we dropped in elevation!

[JimCost2014]

The handle/button furthest right with the biggest number (not the Green one) will work just fine.

Edited July 11, 2020 by JimCost2014

[lt1z]

91 is the minimum recommended given the engine is 11.5:1

[Chevyguy273]

5 hours ago, lt1z said:

91 is the minimum recommended given the engine is 11.5:1

That’s what I thought. Until I was reading the owners manual early this morning. But. My fellow members with more experience helped me out. This forum is the best for GM trucks!! 

[SMW]

I only run 93 about every 10th tank. Run 87 the rest of time. 

[Dunn]

91 is fine

[2020SierraDenali]

87 will work in a pinch, but it could re tard timing to keep from knocking.  I'd use 90 or better if at all possible.  It sort of defeats the purpose using 87.

 

It's recommended that 93 be used, but the truck will work perfectly fine with 91. There's a lot of other variables that could make a difference on how your truck runs at each octane level.

Edited July 15, 2020 by 2020SierraDenali

[Kitz]

On 7/15/2020 at 3:51 PM, 2020SierraDenali said:

87 will work in a pinch, but it could re tard timing to keep from knocking.  I'd use 90 or better if at all possible.  It sort of defeats the purpose using 87.

 

 

It's recommended that 93 be used, but the truck will work perfectly fine with 91. There's a lot of other variables that could make a difference on how your truck runs at each octane level.

Where I live only 87 octane is available unless I want to travel about 30 miles 

[Wintersun]

The manual specifies 93 octane as optimum but you can use down to 87 octane gas in the truck. The 93 octane means it has a higher than normal engine compression ratio and so that pre-ignition rating will provide the most miles per gallon. Using a lower than 93 octane will result in the engine computer automatically retarding the spark to avoid pre-ignition and the end result will be less power and fewer miles per gallon.

 

As Octane only measure the tendency of the fuel to pre-ignite in the engine cylinder before there is a spark from the plug, it is not a linear measurement. 10 gallons of 87  octane and 10 gallons of 93 octane mixed into a fuel tank does not provide a 90 octane mix but something in the 91-92 octane range. When I had a car that took 93 octane gas I would alternate between "premium" and "regular" gas in filling the tank. With 100% 87 octane gas the fuel economy dropped by 2-3 mpg with the car.

 

The Honda Civic and the Honda Accord used the same engine but the Accord used premium gas and provided about a 2% gain in horsepower. The Civic was the smarter buy.