What gas do you use in you 2014 gmc sierra?

[bigsapper]

No but you won't get the full benefit until you're essentially "pure" E85.

[calgator73]

Been emailing back and forth with Blackbear tuning about getting a tune done. They recommend running at lease 89 octane in the 5.3. See the quote below from my email with Justin at Blackbear. I will be more than likely using 89 octane from now on with the tune. I probably wont use E85 anymore because of the crappy mileage and its overpriced by me. Paid 3.72 for E85 last weekend, and 3.55 the weekend before that! Meanwhile since then regular gas has dropped below 3.70! The combination of an 89 octane and a tune from Blackbear, I'm sure I will see similar performance gains like when using E85 but with the gas mileage of regular gas.

 

Is the use of 89 only recommended with a tune?

[fondupot]

Is the use of 89 only recommended with a tune?

They recommend it even without a tune.

 

 

Sent from my iPhone.

[calgator73]

Wonder what kind of power/economy improvement

[fondupot]

Wonder what kind of power/economy improvement

Filled with 89 last night. The tank had a couple gallons of E85 in it tho. But I'll see how it is after a few days

 

 

Sent from my iPhone.

[Silverado-Hareek]

Filled with 89 last night. The tank had a couple gallons of E85 in it tho. But I'll see how it is after a few days

 

 

Sent from my iPhone.

 

Yeah please do I'm curious to see if 89 has any benefits over 87. Either way I'm sticking with Shell gasoline. It's a top tier fuel and I can use my Kroger discount!

[fondupot]

 

Yeah please do I'm curious to see if 89 has any benefits over 87. Either way I'm sticking with Shell gasoline. It's a top tier fuel and I can use my Kroger discount!

 

I will usually use Shell or Mobile. My two favorite stations are kiddy-corner to each other and usually have the best prices within 1 cent of each other. Yesterday I used Mobile because I got a $5 credit on purchases over $30 with my Amex card. So that alone paid for the 89 octane over the 87.

[calgator73]

I've got 7/8 of 87...it'll be awhile for me. I think if I go to 1/2 and fill with premium that will bring me to 90

[JJRS89]

A little over half a tank gone with BP gas (87, I believe). Getting a little worse gas mileage. maybe about .5 a gallon less

[Full Lock]

If nothing else running higher cot. is just alittle added protection for the the engine, being a 6.2 or a 5.3 both run high compression ratios. I know the 6.2 has a pretty high compression ratio 11.5:1 and I believe the 5.3 is 11:1

Please correct me if I'm wrong cause I'm goin by memory

[VMaxtastic]

I started running 91 in my 5.3. Better mileage, and better performance, for like 8 dollars more a tank

[Isriam]

anyone use costco gas? i love it.

[courts94s]

I have a 4.3L and got 80 extra miles when I switched from crap AAFES 87octane to Shell's 91octane. It worked for me!

 

 

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[Brian S.]

I have a 4.3L and got 80 extra miles when I switched from crap AAFES 87octane to Shell's 91octane. It worked for me!

 

 

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I have the 4.3l as well, get 16-17 overall on regular gas, 21-24 on highway trips.

 

Have used the E85 as well and get 13mpg (15-16 Hwy) but it does cost $.50/gallon less at $2.95/gallon.

[courts94s]

I have the 4.3l as well, get 16-17 overall on regular gas, 21-24 on highway trips.

 

Have used the E85 as well and get 13mpg (15-16 Hwy) but it does cost $.50/gallon less at $2.95/gallon.

I averaged 20.7 on this last tank of gas. I got right at 500 miles. I filled up with E85 this evening, so I'll post the results of this tank once it's gone. My put $15 in and messed my whole exact measurement up. But it would have been 500 miles @ 20.7 mpg.