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Discussion Starter · #1 ·
I have a 2011 Chevy Silverado 1500 5.3L v8
And I’m wanting to know how high of a rating I can run in my truck. I do 87 now but my mileage is 10mpg and im wanting to know if I do a higher level will I get better mileage and would it hurt my engine
 

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2015 Silverado LT Texas Edition
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I'm assuming you mean Octane.
Answers are probably not, and no.

How long since you've done a good tune up? What tires are you running? How many miles on the truck?

We need more info...
 

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TO answer your question you can run 93 octane all day long. Will it make a difference maybe a bit with a slight power boost will you notice most likely not. Will it give you better fuel economy more than likely you will not see a difference and if you do it will not be worth the additional cost. Sounds like the truck needs a tune up like others have said.
 

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Higher octane fuel does NOT contain more energy per gallon.
Higher octane fuel does reduce tendency to knock/ping.
Higher octane fuel will NOT hurt your engine.

When engines detects knock/ping they typically adjust timing to prevent engine damage -- and typically produces less power.

Some brands of fuel will have a larger amount of additive per gallon in their higher octane fuels.
This may be a benefit of the engine has had a steady diet of fuel from locations/brands that includes little or no additive.


Some brands have less or no ethanol in the higher octane fuels.
(one brand 'here' has up to 10% in reg, up to 5% in midgrade and zero ethanol in premium grade)
Ethanol contains less energy (btu) per gallon -- so in this case it is possible to get slightly higher mpg.


If the engine will run on E-85, it is very likely that the E85 will get less miles per gallon.
Depending on the relative pricing of E85 in the area, it is possible that running E85 might result in lower fuel cost per mile.


Above posters gave good advice.

First thing to do is determine why it is only getting 10mpg.
It's not because it's running 87 octane.
 
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