MPG, Premium vs Regular Gas.

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Dmuldrock

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Just thought this might be interesting to put out there and get others experience's and opinion on running Premium Gas vs Regular Gas.
I've read a lot of posts saying there are benefits in running premium gas and it will pay for itself but after doing my own test it seems this might not be the case.
I've been getting my gas for my truck at a local Sam's club gas station.
My first 4 tank fulls I filled up with Premium Gas and after doing the hand calculations work out I was getting between 15.4 and 15.9 mpg at an average of $2.48 per gallon.
I ran my next 4 tank fulls on Regular Gas from the same Sam's club gas station and got between 15.3 and 15.9 mpg at an average of $1.97.
I drive for my job and do a mix of city and freeway driving.
I am lead to believe there are added benefits in premium gas that help keep the internal engine components clean but at just over $10 per tank full are these benefits really worth it as there seems to be no gain in mpg? Not between Sam's club premium vs regular gas anyways.
 

Ajwalk2008

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It's mainly because it's a better fuel overall. Less chances of knocking and a few other things


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Divinggumby

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You don't need to go up in quality to get quality gas. I'm not sure what kind of quality Sam's club is but make sure you get quality gas and you should be fine. Also change us the stations since they all have their own additives so one company may do something better than another so if you switch it up it will stay cleaner too. I've found the same results as you with even with a tuner so I stay with 87 since I do 20,000 miles a year and 20-30 cents more makes a big difference. If the truck wasn't used much I'd go for the better gas like I do in the toys and lawn mower since the high test does make a difference when it's sitting majority of the time.
 

Bullitt5339

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If an engine isn't designed for high octane and is in good running order, running anything else is throwing money away and provides no benefits.

As an engine gets older, it may be necessary to move up in octane because of carbon buildup on top of the pistons, valves and in the combustion chamber which does 2 things:

1: It raises the effective compression ration
2: Octane is resistance to burning, so if the engine has carbon buildup, it can form sharp edges in places, which are hotter than the rest of the parts which is prime for detonation. The higher octane resists pre-detonation, which makes it not ping anymore.

The problems are still there, and will eventually get bad enough to where even the highest octane fuel can't help, but it will extend the amount of time you get. I had an old Monte Carlo with 350k miles on it and the valve cover gaskets were the only thing that had ever been done to the engine besides routine maintenance. That thing wouldn't run on 87 octane without pinging itself to death. When I finally tore it down, the valves couldn't even seat fully from all the carbon but I drove it for 80k miles or so running 93 octane in it.
 

sandawilliams

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Just thought this might be interesting to put out there and get others experience's and opinion on running Premium Gas vs Regular Gas.
I've read a lot of posts saying there are benefits in running premium gas and it will pay for itself but after doing my own test it seems this might not be the case.
I've been getting my gas for my truck at a local Sam's club gas station.
My first 4 tank fulls I filled up with Premium Gas and after doing the hand calculations work out I was getting between 15.4 and 15.9 mpg at an average of $2.48 per gallon.
I ran my next 4 tank fulls on Regular Gas from the same Sam's club gas station and got between 15.3 and 15.9 mpg at an average of $1.97.
I drive for my job and do a mix of city and freeway driving.
I am lead to believe there are added benefits in premium gas that help keep the internal engine components clean but at just over $10 per tank full are these benefits really worth it as there seems to be no gain in mpg? Not between Sam's club premium vs regular gas anyways.

I have been driving my 6.4 for two years now and have done the same tests you have. Here in Colorado our regular grade is only 85. Both empty and towing I have never noticed a difference in regular vs. higher octanes. Power and MPG have been the same. The ONLY time I found a difference is when I fill up with 100% gas. Power and MPG increase dramatically. About the only place I can find 100% gas is around the large lakes where boaters fill up. I think ethanol is one of the biggest scams our government ever laid on us>
 

jslowell

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The book says 89 octane. Use it. This is a 5.7L hemi. It is a performance engine not a little four banger. What the heck is the difference of $5.00 per fillup. No knocks, pings and gets 20 mpg.
 
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