2018 Tahoe 5.3l - Gas question

[PappaBear23]

Hey all,

Just bought my first new car ever, my 2002 Chevy Tahoe 4.8l finally bit the dust with 180K, it was so good to me and it had a nice long life!

I'm in a 2018 Chevy Tahoe 5.3L its amazing so far, I miss some little quirks from my other one, but overall its a huge upgrade!

In the owner's manual it says to use top tier gas and at least 87 octane fuel. I've already figured out what top tier fuel is but is there any real difference in running 87, 89, or 91 octane gas?

I would love to know because the difference price wise between 87 & 89 are minimal where I am and I'm wondering if I'll get better gas mileage and power running 89.

Thanks,

- Colby

 

[AZCreeker]

I only put 87 in mine.
My Suburban sucks so much gas, i'll get the cheapest I can find.
FYI here is some recent articles about how higher Octane might not be worth the increase in cost.

https://www.roadandtrack.com/car-culture/buying-maintenance/a14425998/premium-gas-fuel-benefits/

 

[swathdiver]

You will almost always get better mileage running higher octane fuel. How much so depends on where and how you drive. Low octane fuels generally do not have the detergents in them that keep your fuel system clean.

Not all brands deliver the same performance either. Start a log and run a couple tanks of each while running the same profile to get an accurate comparison. If I want to lose 2 mpg and run 93 octane, I can always count on Shell to deliver the loss! If I want to lose 4 mpg, then Cumberland Farms' fuel is happy to oblige.

In thirty years it has been my experience that it costs more to run the cheap stuff than the good stuff. Don't think in terms of price per gallon, but rather, cents per mile.

For example, would you rather pay $2.99 a gallon for regular and get 12 mpg or $3.38 a gallon for high test and get 15 mpg? In this example, it costs $.25 a mile to run the "Cheap" gas and $.22 1/2 cents a mile to run the "Expensive" gas.

You'll have to work out your own numbers. One fella here with a K2 saw no difference.

 

[cardude2000]

Just depends on if you want max HP and efficiency from the vehicle. Wont hurt the vehicle to use 87 though.

 

[swathdiver]

Just depends on if you want max HP and efficiency from the vehicle. Wont hurt the vehicle to use 87 though.

It does hurt. Most of the fuel system problems we see here are from folks feeding their motors that swill. Clogged injectors, pumps whining, carbon deposits on their valves and pistons, etc. Granted, direct injection won't have fuel cleaning their valves but that's not the point. We didn't even address the poor performance, knocking and pinging.

 

[cardude2000]

It does hurt. Most of the fuel system problems we see here are from folks feeding their motors that swill. Clogged injectors, pumps whining, carbon deposits on their valves and pistons, etc. Granted, direct injection won't have fuel cleaning their valves but that's not the point. We didn't even address the poor performance, knocking and pinging.

On a 2015+ those issues would have nothing to do with using 89 vs 91.

That has to do with using crappy off brand gas.

 

[Tahoe14]

87 octane at Exxon/Mobil vs TomThumb convience store would be a big difference. I disagree that using a top tier 87 octane would cause a problem.

 

[Shadowchaser]

i use Diablo Itune2 with straight V8 setting (AFM disabled) alway use 89 and my average 16-20 mpg's

 

[PappaBear23]

You will almost always get better mileage running higher octane fuel. How much so depends on where and how you drive. Low octane fuels generally do not have the detergents in them that keep your fuel system clean.

Not all brands deliver the same performance either. Start a log and run a couple tanks of each while running the same profile to get an accurate comparison. If I want to lose 2 mpg and run 93 octane, I can always count on Shell to deliver the loss! If I want to lose 4 mpg, then Cumberland Farms' fuel is happy to oblige.

In thirty years it has been my experience that it costs more to run the cheap stuff than the good stuff. Don't think in terms of price per gallon, but rather, cents per mile.

For example, would you rather pay $2.99 a gallon for regular and get 12 mpg or $3.38 a gallon for high test and get 15 mpg? In this example, it costs $.25 a mile to run the "Cheap" gas and $.22 1/2 cents a mile to run the "Expensive" gas.

You'll have to work out your own numbers. One fella here with a K2 saw no difference.

Thank you so much! Yes I only picked up the car two weeks ago in NY, I got back to MA where I live and filled up with Cumberland farms gas and immediately noticed the difference of mpg. I'm switching over to Phillips 66 next time I fill up, looks like they are the best around quality wise.

 

[swathdiver]

87 octane at Exxon/Mobil vs TomThumb convience store would be a big difference. I disagree that using a top tier 87 octane would cause a problem.

Try it. Try Shell's 93 and Mobil's 93 and then Chevron's 93 too.