Does the 5.7 get better MPG with higher octane?

Does using a higher octane have any benefits in the 5.7 and is Seafoam additive good for them.

 

MPG does not improve with higher octane fuel nor will the engine make more power. I can’t speak for Seafoam.

 

https://www.tundras.com/threads/87-octane-vs-91-octane.6820/

good read right there.

 

A coworker who has had 8 tundras swears by Seafoam. I haven't used it yet but plan to look for it soon. Unsure if it would make much of a difference but I would add this recommendation to the side of "doesn't hurt to try"

 

I have used a can of Seafoam in the tank on every vehicle and I think it helps clean them. One time I used it directly in the carb on a 2008 Dodge Dakota and it belched white smoke like a train. I thought I had blown a cylinder but once it cleared up it ran like a top.

My 2020 F150 actually did better MPGs using 91 octane even if it was just 1-2 better.

 

assuming your 2020 f150 is ecoboost, it does run better using higher octane because it's turbocharged.
Turbocharged motors (e.g., the Ecoboost) do benefit from higher octane fuels, because they are designed to do so. But if your NA motor (like the 5.7) is designed to run on 87 octane, then running 89, 92, 93 or similar octane fuel will accomplish little more than emptying out your wallet for no reason.

 

OK so how about ethanol vs. non-ethanol fuel in the 5.7, and benefits or reasons to not run ethanol blend. I know my small engines like the weed eater and chainsaw HATE the ethanol and it plugs up the jests from eating gaskets.

 

I just follow the user's manual, and the gas cap which says not to exceed 15% alcohol blend.
I've never tried pure gas. It's hard to find pure gas anywhere (at least in my area). even using https://www.pure-gas.org/ does not help me lol. I use Shell or Chevron 87 and I am happy with it.
Some areas have pure gas with Shell 91/93 and drivers have reported better gas mileage with that. Or could just be placebo effect?

 

I am in AZ and the Maverick chain of stores has "Blue Gas" that is non-ethanol. I also like Chevron fuel with Techron, it is what trucks crave.

 

seems like neighboring states all have pure gas but not NV!

 

Octane shouldn't change mpg, but it may if the engine is pulling timing. Likewise non-ethanol potentially can increase mpg since it has a higher power density than ethanol so one gallon should take you further.

With all that said, if you're trying to save money what you really want to know is dollars per mile. If you get twice the mpg with a different fuel but it costs three times more, then you're not saving any money even if the mpg is better. Higher octane and non ethanol (at least at Maverick) cost considerably more, so make sure you're actually saving money if that's your intent.

 

100% 87 is best, throw in a couple cans of Berryman's b12 in a half tank every other oil change for clean injectors and intake valves.

 

I keep hearing about berrymans. Never tried it, but i may try it now

 

I use premium because it’s the only one without ethanol around here. I’m probably wasting money. I won’t put ethanol gas in my lawn equipment either.

 

i would too if I can confirm that the Shell premiums in my area are 100% gas...I have heard about it but I can't confirm.

 

i don't have an engineering degree so take it or leave it but i generally don't use additives that aren't recommended by the manufacturer. The idea that seafoam has the same exact effect on 2-stroke or 4-stroke and works on 5hp all the way up to your italian supercar engine doesn't sit well with me.

 

I wouldn't trust anyone who has had to buy 8 Tundras...just sayin

 

I use mid-grade on my 2015 5.7L. Almost all highway driving, with 300lbs of armor on it, and, according to the dash, I average 15.5mpg.

I would swear the truck performs better with 89 vs 87. My uncle, who is a Toyota Master Mechanic, also runs mid-grade. He says the same thing: there is more 'get up and go'. It makes the drive more fun!

I also ran 89 in my 2010 Sienna (3.5L v6) for the same reason. I'd swear it performed better.

But maybe it's all in my head?

That said, I wouldn't use premium unless you have a supercharger.

EDIT: My 5.7 is an FFV, which may or may not matter.