Better MPG on 93?

[StevenStarke]

I think i read someone else say this but I don’t remember. I tried a full tank of 93 and I swear to god, it seemed like I got better MPG? I didn’t track miles or anything but I may have to. Anyone else notice this? I’m curious to see if it’s better enough to justify the extra cost?

[lew-e]

I’ve noticed this. Others have noticed it too. Some say it’s an anomaly because you actively try to get better mileage when you are paying attention to it. However, I found I had better engine response and mpg. The cost was not offset though. You figure I’m paying 1.90 a gallon for 89. Or 2.50!!!!!! for 93? I’d need to be adding a ton of mpg to offset the cost. Instead I saw 1-2 mpg difference


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[KA0S]

Be careful, the resident mathmagician will be all over you for those comments.....[emoji849][emoji849][emoji849][emoji849]

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[Sierra Dan]

Which engine? 5.3 or 6.2 ?

Must be the 6.2 as Premium is "required" 

[Capt Bob]

I'll guess one would need to see a 6 mpg increase with the higher octane to break about even.

 

Engine displacement isn't a factor.

Edited January 16, 2019 by Capt Bob

[StevenStarke]

I have a 5.3. 87 octane is 2.35ish here in NY and 93 is like $2.80.  It’s prob not worth it. But i wasn’t paying attention to it, I just noticed it took longer to go down than normal. AND I added 34” tires right after filling up on 93. 

[aseibel]

You can decide if you trust these sources, i'm just sharing.

 

"If your car does not require premium gas, there are no added benefits to your car’s performance or longevity. Simply put, you’re paying good money for something you don’t need. Premium costs 15-30 cents more a gallon than regular. In a consumer notice, the Federal Trade Commission, notes: “In most cases, using a higher-octane gasoline than your owner’s manual recommends offers absolutely no benefit. It won’t make your car perform better, go faster, get better mileage or run cleaner.”

https://www.truecar.com/blog/2011/03/03/premium-vs-regular-gas/

 

"Designed for performance cars with large, powerful engines, premium also helps minimize the risk of preignition inside highly-stressed, hot engine cylinders. On a track, the extra boost given by premium can mean a few tenths of a second difference on a lap time.  In the real world, it barely affects performance, or fuel economy."

https://www.greencarreports.com/news/1077286_busted-7-things-that-wont-improve-your-gas-mileage

 

[L86 All Terrain]

Giving the engine a higher octane (more resistant to pre-detonation, knock, or early combustion) allows the ECU to advance the ignition timing and variable valve timing. Advanced ignition timing leads to a more thorough and complete burn of the A/F charge, which means more power per RPM. This means the engine can become more efficient and make more HP per gallon. This can easily work the other way also, if you are making more power, and using it, you will burn more fuel. If you are loafing around just as easy on premium vs. regular, you should in theory get better mileage on premium but I would not expect the savings to pay off the difference in the price.

 

These new LT family DI motors have a high compression ratio, even the 5.3L L83 is a 11:1 with the L86/87 being 11.5:1. Consider that compared to yesterdays 5.7L Vortec 350cid engine, which was at a 9.5:1 compression ratio, and the hotrodders ran 91+ in anything over 10:1 in the 90's. That alone is enough to convince me to use 89+ oct or E85 if available at all times. 

[M1ck3y]

The 6.2 is designed for 93, says right in the manual that 93 octane is highly recommended. No different then the vette. If shell had 93 octane where I am, I would be all over it. Or at least if I could find a 93 without ethanol (which is impossible?). Not because it gives better mileage (it will a bit) but because its the best I could run in it. If I wanted I could run 87 but mpgs will drop and power output will drop. But, in the long run I'd probably save money.

[DONWT15]

1 hour ago, M1ck3y said:

Or at least if I could find a 93 without ethanol (which is impossible?).

Try looking in areas that cater to boaters. Gas with ethanol is the kiss of death for outboards. They sit for months at a time and the ethanol separates out.

[gothp28]

I have a 5.3. 87 octane is 2.35ish here in NY and 93 is like $2.80.  It’s prob not worth it. But i wasn’t paying attention to it, I just noticed it took longer to go down than normal. AND I added 34” tires right after filling up on 93. 

If you have a 2019 please post pictures with the 34s. Not too many pictures floating around.

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[StevenStarke]

[gothp28]

Truck looks great! Did you have to have any rubbing? Lift? Offset? I take delivery of mine in 2 weeks and would like to purchase rims and tires. Sorry for all the questions but I appreciate any answers that you give.

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[Mardo]

20 hours ago, StevenStarke said:

I think i read someone else say this but I don’t remember. I tried a full tank of 93 and I swear to god, it seemed like I got better MPG? I didn’t track miles or anything but I may have to. Anyone else notice this? I’m curious to see if it’s better enough to justify the extra cost?

I'm in Arkansas and our local Walmart has 93 octane with no ethanol for around 50 cents more than 87 octane with ethanol. I figure I get 2-3 mpg more with the 93 without ethanol. It may not be worth it mpg wise but it sure seems to run better on 93 without ethanol. I have an AT4 with 6.2.

Edited January 17, 2019 by Mardo

[Texas Daddy]

Blackbear posted an article years ago about the ls truck engines needing higher octane with their increased compression ratios. The gen 4 5.3 likes 89 better than 87, and you can tell a difference...

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