2018 Tahoe 5.3l - Gas question

[RThomasII]

2016 LTZ here... Purchased brand new with 10 miles on the odometer when I drove it off the lot. I ran 87 (Shell & Exxon) for about the 1st 6 months of ownership. Then I read on here that with the compression on the 5.3 we really should be using a higher octane gas. I stepped up to 89 and I swear my truck ran better. I then stepped up to 93 and I've been there ever since. Maybe it's the placebo effect.... I don't know.... But for me the higher octane gas seems to make a big difference in the operation of my Tahoe.

For what it's worth... It was the guys over at Black Bear that posted the stuff about compression and the 5.3. I know they are a trust source around here. YMMV.

 

[thirdcoast]

OK Pappa Bear, I also have a 2018 Tahoe that I bought new in January.

I run 89 octane exclusively in this Tahoe and ONLY run major brand fuel in my vehicles.. I generally use Exxon as there is a large facility near my home and they are very busy so no old fuel in the tank// Plus it is owned by the largest fuel distributor in my area..

I track my MPG pretty close and here is what I have been getting:

Last trip to San Antonio, 156 miles one way with an average MPG of 23.4 @ 77 MPH on cruise..

Around town with occasional short highway spurts average MPG 16.7

Last combo town & highway average MPG 20.1 at speeds between 35 & 75..

Now in full disclosure, I have a Corsa catback exhaust & a CAI on the truck and I also run my tires at 37 PSI.. BTW, these MPG's are with the AC on as it has been 95+ for a while down here in South Texas..

In my 2009 6.2L Tahoe I only run 93 octane..

Good luck and stay out of the waldomart gas stations

Thirdcoast

 

[swathdiver]

I can only best my mileage on Exxon/Mobil with a good tank of Chevron. Haven't had good fortune to get consistent fills from them yet.

The mileage you guys get with those L83 is what I was getting twelve years ago with my SV6 Montana with the 240 horse V6 motor. That particular car get better mileage the faster you went. Mileage was down to 21 @ 70 but up to almost 24 at 77 mph. It got a solid 21 mpg at 90 mph too! Miss that car.

 

[tdriver113]

Black Bear tune for 93 octane.
17 MPG around town. 22 MPG on highway driving at 70 MPH.
And that stupid AFM turned off.

THANK YOU BLACK BEAR.

 

[Greg Treantos]

Top Tier is a branding campaign. Gas stations that follow their rules get the mark. I usually go to Costco for my gas and they passed Top Tier's requirements. Here is a list of other dealers that are Top Tier branded

 

[georgebuhr]

Personally, I would recommend running the higher octane, and preferably find some with no ethanol in it. Some of the Loves gas station carry 91 with no ethanol around here, and there is a local station less than 4 blocks from my house that has 91 with no ethanol. I run that whenever I can, in whatever I can. It should give you the best mileage with the least amount of deposits. After seeing what ethanol can do to a small engine, I am not comfortable running it in a car. I will use it, but switch back to no ethanol whenever I can. I don't think it is as big an issue in a car as it is small engines, because they tend to sit much more, but other than cost, I see no benefit to having ethanol in a tank.

 

[Miami-Dade]

I only put 87 in mine.
My Suburban sucks so much gas, i'll get the cheapest I can find.
/

I would not buy the cheapest fuel I can find. I would only buy top tier fuel like Exxon-Mobil.

2016 LTZ here... Purchased brand new with 10 miles on the odometer when I drove it off the lot. I ran 87 (Shell & Exxon) for about the 1st 6 months of ownership. Then I read on here that with the compression on the 5.3 we really should be using a higher octane gas. I stepped up to 89 and I swear my truck ran better. I then stepped up to 93 and I've been there ever since. Maybe it's the placebo effect. YMMV.

It is the Placebo effect. It does not run any better. The 5.3 does not need 89 or higher for your compression ratio. That is one of the reasons why GM went to Direct Injection.

Personally, I would recommend running the higher octane, and preferably find some with no ethanol in it.

Good luck on finding no ethanol in my neck of the woods or anywhere from Key West-NYC. It is not going to happen. I wish I could find no ethanol fuel.

While I was in Virginia I visited a friend who has a 2015 Yukon with the 5.3. He drove my Tahoe on I-95 and on surface streets. He has been using 89 and said he saw zero difference in his Yukon and my 87 octane Tahoe so he going to change back to 87.

I worked for company for awhile that had several 1999-2008 Tahoe's. They all ran perfectly fine on 87 for over 200K miles. No clogged injectors,no carbon deposits on valves and pistons. We did use Top Tier fuel and all vehicles were serviced regularly.

If I have any issues running 87 in my Tahoe I will let everyone here know.

So far I have not heard of anyone complaining of carbon buildup [or performance issues] on their 2015 plus 5.3 or 6.2 Direct Injection engines. Even ones with over 150K miles.

I can not believe how many people are brain washed into thinking 89 or higher octane is better for their 5.3 vehicles. I am sure the oil companies love that.

All that is just IMHO. To each their own.

 

[swathdiver]

Good luck on finding no ethanol in my neck of the woods or anywhere from Key West-NYC. It is not going to happen. I wish I could find no ethanol fuel.

Many Racetrac stations sell Ethanol free fuel Gary. Also, along US27, between Palmdale and Haines City are a bunch of stations that sell 93 octane free of ethanol. Most only sell 89 or 90 octane like Racetrac, which is right up your alley anyway! But, neither of us frequent Bloody 27 though we do go to Davenport/Haines City once every year or so.

I remember when ethanol laced fuel was mandated that my other cars lost about 2 mpg. The only benefit to us, the consumer, is that it helps prevent detonation.

 

[Tahoe14]

Try WaWa in central Florida as they have Ethanol free.

 

[Miami-Dade]

Many Racetrac stations sell Ethanol free fuel Gary. Also, along US27, between Palmdale and Haines City are a bunch of stations that sell 93 octane free of ethanol. Most only sell 89 or 90 octane like Racetrac, which is right up your alley anyway! But, neither of us frequent Bloody 27 though we do go to Davenport/Haines City once every year or so.

I remember when ethanol laced fuel was mandated that my other cars lost about 2 mpg. The only benefit to us, the consumer, is that it helps prevent detonation.

Try WaWa in central Florida as they have Ethanol free.

Thanks for info guys!!

When ethanol first came out I had 4.6 V8 Town Car. I lost about 2 mpg just like you said immediately. I hear you on Bloody 27. Bloody 27 and Krome are the worst.

I will not buy RaceTrac fuel as a friend got a tankful of dirt in his Mercedes a couple of years ago at a RaceTrac in Broward County off I-95. This station is a super busy station 24/7. 1500 bucks later [dealer serviced] it was running good again after it was towed in.

When I go thru Central Florida Gary I barely get off I-95. But good to know.