00pooterSS

iTrader: (40)

10-15 is 10-15

93 octane costs roughly 8$ more a tank than 87, and $4 more than 89. No point in going 89 IMO. The additional MPG cancels out the additional cost. And even if 93 didn't do much better than 89, which it will, it's 6 points higher than 87 vs only 2, it's only $4 a tank, and it will will also cancel out.

ALL engines can run more timing at ALL times on higher octane.

FFDP

iTrader: (2)

If it means that much to you, by all means do it.

There is still a point where timing stops allowing you to gain MPG/Horsepower and the one could be achieved with either octane. A dyno would be ideal to see where peak torque stops.

00pooterSS

iTrader: (40)

Yeah at some point it maxes out, I hear ya. But we both agree there will likely be more peak power and the cost is pretty insignificant so I'd just rather go with 93.

Honestly I wanted a 6.2 truck but couldn't find any in the price range I wanted to pay so I'm gonna do a couple of things to the 5.3 to get it up to 6.2 ish power but make sure I don't **** away MPG while doing it.

Noah Burns

iTrader: (5)

When I went to LTs I had ORY with MBRP catback. I always got worse mileage with higher octane fuel so unless I was going to be hard on it I ran low grade (87 around here)

00pooterSS

iTrader: (40)

Also good to know about the octane. I've had this truck less than a week and still learning.

03sierraslt

iTrader: (22)

Mines all stock, that I can vouch for... mine gets the best on 87, in fact I’ll go as far as to say I can feel the power loss on 93. These DI motors are sensitive, mine runs better when it’s warmer outside also. I suspect the fuel atomizes better with higher charge temps.

All the complete opposite of my 04.

1994Vmax

iTrader: (4)

When I had my 2015 6.2 we tuned it. The power pick up was good and the afr was a lot more consistent but mileage never improved. Buddy tuned his 2014 5.3 truck and it's night and day for power... again mileage has not changed. Stock is pretty normal on these... the physics of a brick come into play.

Yes I tuned my 17 and it's just getting worse the more I do because the mods are not for gas mileage lol... not that I care anyway haha.

I will be honest that I have had at least a dozen tuned vehicles by different tuners and whatnot... not one got better economy after.

TXsilverado

iTrader: (19)

are you wanting good mileage to save money, or just for bragging rights? you need to look for bang for buck if it's about saving money.


any additional mileage that you MIGHT get with that 93 octane will not equate to an $8 saving per tank over 87 or 89.


it's like people thinking e85 is the answer. yes, it's cheaper up front, but you fill your tank nearly twice as often. where is the savings?

arthursc2

iTrader: (5)

Either because I subconsciously drive different, or the tune had an impact, I picked up a consistent 2mpg after my last dyno run. I went from 10.5-11mpg city to a clean 13, and on the highway I moved from 13 to 15 unloaded.

Loaded I am still 8-9. It was like that stock.

Best it ever saw was 19mpg on the highway lol.

Atomic

iTrader: (42)

Also keep in mind people lie, especially on the internet. Bragging about MPG is almost as bad as people bragging about HP

Giving the benefit of the doubt, they may just trust the cluster info instead of actually measuring from the pump and dividing range by that. Also need to verify speedometer is calibrated correctly to tire size.