Super Unleaded

FreeAmerican · February 3, 2017

I have been using 93 consistently for some time (over a year) I normally buy gas at Sam's / Costco and the 93 is what 89 is at most other places. (My Sam's does not have 89, just 87 and 93)

When I bought my truck I ran 87 for a month, recorded mpg then ran 93 for a month and did the same. This was all on summer gas and temps and my driving (back and forth to work were all the same. I did pick up 2 mpg.

So over a year I am spending $50 over 10,000 miles. No brainer for me.

mookdoc6 · February 4, 2017

Geez.... You couldn't be more wrong. Tuners all over have said the running at least 89 is a real benifit for this high compression engine.

RT

Without a doubt the 5.3 runs 50% better on 89 than 87......It's apparent almost immediately!

GMC2015 · February 4, 2017

Without a doubt the 5.3 runs 50% better on 89 than 87......It's apparent almost immediately!

Made a difference in my 4.3 running 89 over 87.

mookdoc6 · February 7, 2017

I am the least likely person to ever put more expensive higher octane rated gas in a engine that does not specifically mention it needs 91-93 minimum. Anyway, the forums having read their posts and I tried it one day! Well no crap! I never even bothered to know what the compression ratio was of this Gen 5.3. Yeah, it likes 89 and it's not a placebo..........

Cowpie · February 12, 2017

All I run is 93 in my trucks. Sure, they will run on 87, but I hate the reduced power and valves clattering when pulling a trailer.

You pull a trailer all the time? I could see where premium could be of benefit under hard pulls and heavy loads. But am not convinced it is necessary for general driving situations.

But if it is all about octane, which is the only difference between regular and premium, then for a 5.3 that is flex fuel, just use higher blends of ethanol. Low end regular E15 in my area is 89 octane. And a dime cheaper per gallon than regular. E85 is 100 octane, and about 60 cents a gallon cheaper in my area than regular.

And the cost. Lets use as an example that I get 15 mpg on regular. At the current price in my area, $2.22, that is about 14.8 cents a mile cost. Say I get a couple mile per gallon better with premium, for the cost in my area, $2.75, and getting 17 mpg, the cost would be 16.2 cents a mile. Now the fuel economy drops with something like E85, even though the actual performance may be better. Lets say it drops to 12 mpg. At $1.69 a gallon in my area, the cost is 14 cents a mile. Premium performance at a cost per mile that is less than regular. No brainer.

FreeAmerican, I did the 10,000 mile calculation that you say only costs you an extra $50 a year, on the numbers I just gave. Came to about $140 extra cost to use premium with the fuel prices in my area. Having a better mpg has a warm fuzzy feeling I guess, but if it actually is costing me more per mile to get it, then what is the benefit?

FreeAmerican · February 13, 2017

You pull a trailer all the time? I could see where premium could be of benefit under hard pulls and heavy loads. But am not convinced it is necessary for general driving situations.

But if it is all about octane, which is the only difference between regular and premium, then for a 5.3 that is flex fuel, just use higher blends of ethanol. Low end regular E15 in my area is 89 octane. And a dime cheaper per gallon than regular. E85 is 100 octane, and about 60 cents a gallon cheaper in my area than regular.

And the cost. Lets use as an example that I get 15 mpg on regular. At the current price in my area, $2.22, that is about 14.8 cents a mile cost. Say I get a couple mile per gallon better with premium, for the cost in my area, $2.75, and getting 17 mpg, the cost would be 16.2 cents a mile. Now the fuel economy drops with something like E85, even though the actual performance may be better. Lets say it drops to 12 mpg. At $1.69 a gallon in my area, the cost is 14 cents a mile. Premium performance at a cost per mile that is less than regular. No brainer.

FreeAmerican, I did the 10,000 mile calculation that you say only costs you an extra $50 a year, on the numbers I just gave. Came to about $140 extra cost to use premium with the fuel prices in my area. Having a better mpg has a warm fuzzy feeling I guess, but if it actually is costing me more per mile to get it, then what is the benefit?

Morning Cowpie

The differential between your calcs and mine is the cost of premium vs regular. At my Sams's club the difference between regular and premium is between 25 and 30 cents where yours is 50 cents. But Sam's only has reg and premium, no 89.

You really don't notice a HP increase by the seat of the pants, it torque you notice and to even notice you need to pick up 5-10 foot pounds across the rpm band. Along with better mpg, I do feel a difference in the truck along with it going into V4 mode sooner and staying there longer.

More evidence is logging the timing retard. Its not pulling as much timing which = hp/tq.

So for me its worth it. In your case with the cost of gas in your area, and if you are not towing, I prob wouldn't either.

Its like the smart cars, they get better gas mileage but at the cost of the required premium gas, a small Honda burning regular can be more economical.

Amuro · February 14, 2017

Prior GM Tech and programmers/ tune aside, from my experience and what I was trained majority of our trucks/ my 2016 5.3 has been designed and tuned for regular Octane, it was designed to use regular gas period. So using High octane/ it's not a high compression engine/ not running a supercharger nor turbo so it's a waste of money purchasing high octane fuel in a vehicle that was designed to run on regular. I've also heard If you are hauling something heavy use premium but I personally never pulled anything heavy at all, and I would probably stick with regular if i did anyways. Also I had a chance to visit and speak with some of the guys at GM Arlington assembly plant, from their mouth, if you are going to haul something use regular ol gasoline not E85/ flex fuel trucks, due to the BTUs of E85 vs Gasoline, I'm sure people now know this but this question was asked when the whole new Flex fuel came out on the first GM trucks. My 2012 Tacoma was designed to run regular and 85k later it runs perfectly fine, 2016 Chevy 5.3 in the owners book states to use regular and runs perfectly fine, runs smooth with no issues. Just my 0.2 worth of info. At the end of the day do what makes you feel happy inside, and if running premium fuel makes you happy despite it's NOT designed to run premium then go for it!

Cowpie · February 14, 2017

The cost is variable depending on region. Some places, E85 is not really a good option since it has no good cost spread.

FreeAmerican · February 14, 2017

I can't even find E85 around here.

FreeAmerican · February 14, 2017

Prior GM Tech and programmers/ tune aside, from my experience and what I was trained majority of our trucks/ my 2016 5.3 has been designed and tuned for regular Octane, it was designed to use regular gas period. So using High octane/ it's not a high compression engine/ not running a supercharger nor turbo so it's a waste of money purchasing high octane fuel in a vehicle that was designed to run on regular. I've also heard If you are hauling something heavy use premium but I personally never pulled anything heavy at all, and I would probably stick with regular if i did anyways. Also I had a chance to visit and speak with some of the guys at GM Arlington assembly plant, from their mouth, if you are going to haul something use regular ol gasoline not E85/ flex fuel trucks, due to the BTUs of E85 vs Gasoline, I'm sure people now know this but this question was asked when the whole new Flex fuel came out on the first GM trucks. My 2012 Tacoma was designed to run regular and 85k later it runs perfectly fine, 2016 Chevy 5.3 in the owners book states to use regular and runs perfectly fine, runs smooth with no issues. Just my 0.2 worth of info. At the end of the day do what makes you feel happy inside, and if running premium fuel makes you happy despite it's NOT designed to run premium then go for it!

In what world is 11 to 1 not hi compression?

Amuro · February 14, 2017

In what world is 11 to 1 not hi compression?

I never searched or care to check what the compression is on my 5.3 to beggin with, and I stated refer to your owners book which states use regular fuel, not High octane fuel. My assumption due to the fact of regular ONLY is that the engine in my truck is not a high compression engine. And I would still say refer to the owners manual in reference to what gasoline octane to use for your engine, 5.3 or 6.2. Put whatever you want, it's your truck.

FreeAmerican · February 14, 2017

I never searched or care to check what the compression is on my 5.3 to beggin with, and I stated refer to your owners book which states use regular fuel, not High octane fuel. My assumption due to the fact of regular ONLY is that the engine in my truck is not a high compression engine. And I would still say refer to the owners manual in reference to what gasoline octane to use for your engine, 5.3 or 6.2. Put whatever you want, it's your truck.

I think you are a little off on your statement. The manual states ( and I just copied / pasted right out of it)

Use only unleaded gasoline rated 87 octane or higher

I just wouldn't say the motor is not designed for higher octane, the manual just lists a min octane, a floor so to speak.

But as you say to each his own.

FreeAmerican · February 14, 2017

I will add this line from the manual as well. For the 6.2 which is only .5 higher compression than the 5.3

Use premium 93 octane unleaded gasoline in your vehicle. Unleaded gasoline with an octane rating aslow as 87 may be used, but it will reduce performance and fuel economy

07Softail · February 14, 2017

Gas threads are like oil threads FUNNY AS HELL!!! Will the truck run on 87? Yes it will, But will it run as good as 89 No it won't. GM states that it can run on 87 to get the customer to bite on a new vehicle that can run on 87 pump. It's marketing and as I recall when buying my truck the dickhead salesman said that very thing (you can burn cheap 87 gas)!

RT

Amuro · February 14, 2017

From what I recall/ my truck is at the dealership for repairs so I can't check right now right now, it was regular unleaded for the 5.3 and IF I remember correctly if not please correct me if I'm wrong, the 6.2l was premium. That's the little I remember from my owners manual. When I purchased the truck I forgot to ask the sales person what octane level to use on my new truck. I checked on the owners Manual and I recall regula for the 5.3 but I will check and have no issue admitting I'm wrong on what I recalled from the book