Shell gas MPG

Does Shell gas give your car more MPG?

Since it was new I’ve been using regular 87 octane gas from Fred Meyer (Kroger) in my 2018 Versa manual 5 speed with 57000 miles. MPG has averaged 41 since new but the last 3 fill ups were with Shell 87 octane regular where average MPG has gone up to 45.3. I’m starting to think there really is something to the idea that all gas is not the same. Has anyone else noticed improved MPG with different brands of gas?

It’s possible for different brands to give you different MPG’s.

The amount of ethanol can also affect MPG’s

It’s also that time of year where summer blend gas is showing up which will also increase your MPG’s

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Ethanol labeled 10% on both brands. Have not seen MPG go up when the switch to summer blend happened over the last 5 years.

Shell is more expensive than Kroger so I’ll have to calculate which is cheaper overall.

In another century I drove a lot as a salesman. I kept detailed records on gas cost, mileage, maintenance etc. Back then I found that Gulf premium gave me the best cost per mile. The cost per gallon was higher but the mpg improvement made it worth buying. That changed sometime in the early 1980’s (I think Chevron took over parts of the brand) After that I did not see the difference.

This was also the time when octane rating of gasoline was boosted with increased long chain hydrocarbons that were harder to autoignite but also had more energy. Now days octane is boosted with additives that suppress ignition under pressure

@It_s-Me make a good point about ethanol content. Most pumps state “up to 10%” ethanol. If the tank farm that supplies Shell gas was short ethanol they may have shipped ethanol free gas . That would give a slight boost in mileage. But with the tight cost control Shell and the other big boys have I doubt that will last long if that happened.

Probably says “May Contain Up To 10% Ethanol”

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Gasoline typically comes from the same tank farm and specific brand additives are then infused. The additive that most affects gas mileage is ethanol and it decreases mileage. It seems to me that enough ethanol is added to achieve an 87 octane rating and that could be up to 10%. I suppose they could use other legal octane enhancers but I’m not familiar with the legal additives.

To average 41 mpg you had to have many tanks get over that and some getting less . I don’t ever remember getting the same mpg reading 3 times in a row .

I get my best mpgs in spring and fall, when temperatures are moderate. Have you noticed the same thing? It may be seasonal variations.

I don’t have a Shell close enough to me know. Years ago, when I lived or worked close enough to a Shell station - I always found them to be a good quality but usually more expensive than other.

Mobil on the other hand - has always given my vehicles WORSE performance. Golf and Sunoco are good. Around here in NH I use Iriving gas. Top Tier gas and usually one of the cheapest.

Once in a while if I’m driving I’ll punch the mpg button just to see but otherwise I don’t obsess over mileage. The guy that used to own the Mobil station also had bulk service. He owned his own tanker and would fill up at the same refinery everyone else used. I worry more about water and junk in the gas.

Finally a topic I can confidently share my knowledge or experience without feeling guilty.

I have always gotten better MPG with SHELL compared to other brands. Always.

It is so noticeable that the entire family uses shell, but some friends avoid shell due to the higher price.

When I full the tank right up and travel exactly 50 miles, the gas info on the dash slightly moves. This is constant with my driving behavior. The gas needle slightly moves at exactly 50 miles of travel when I use shell.

But the needle always moves at 40 miles of travel when I use Sunoco and Mobil. Some times I might get lucky to get 43 miles.

I also noticed power differences . Like my car kicks in lower gear when using shell, giving the car a boost without having to depress the accelerator too much.

I pay attention to gas mileage, too, and have also noticed that some brands of gas provide better MPGs.

However, I’ve also sat down and done the math. Sometimes, using round numbers… if I get 2-3 more MPG using Shell, but it costs $0.15 more per gallon… have I really done myself any good?

I’ve especially noticed this with the price of “pure” non-ethanol gas in my part of the world. No doubt you get more MPG…but it costs $0.50-0.75 more per gallon. It’s not that good.


I use the non oxy for my small engines. I don’t remember what I paid last week but yeah at least an extra 75 cents. Well worth it though to not have fuel problems in my mower, blower, generator, pressure washer and chain saws. Never had a problem again after switching about ten years ago. Just sayin is all. But I always use conditioner too, but I hate that perfumed stuff from Walbro.

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I’ve just been using Sea Foam - 1oz / gal when I fill the cans. It stabilizes, and I assume helps keep things clean.

My driving is pretty consistent, all mountain highway, 40 MPG is the lowest I’ve seen. I saw 47 once but considered it a fluke. Maybe I had filled up with Shell or another brand that time.

Yeah I used to use sta bil, then a small engine shop said it was junk. So then I switched to the Briggs brand until they discontinued it . So now it’s Walbro from the carb guys, but it stinks like French perfume. You know the rest. Never dated a French that I know of so I may be just full of it. At any rate it gets on your hands and wife wants to know whose perfume that is. Just kidding but it does stink

Ah, just switch to the Seafoam. Aren’t you from Minnesota? The Minnesotans are supposed to love the stuff, what with the 10,000 lakes and thus all of those boats and stuff. It doesn’t smell like much of anything at all. Maybe it can keep your small engines good AND keep you out of trouble with the wife :wink:

Seafome for the boats, never noticed any gas mileage gain from any top tier gas., including BP that evidently is not top tier anymore.

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I haven’t responded to the main issue in this thread b/c I think it’s a red herring. I don’t gas up by brand or even pay much attention. And any variation in MPG is very likely a) nearly impossible to measure accurately, and b) if it exists at all probably due to variations in ethanol content, as was already noted.

As for Seafoam and small engines…I give it a thumbs up.

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I am just going to admit that I am a skeptic. Never less than 40 mpg ( how does someone exceed the EPA mpg all the time ) ? The same exact mpg 3 times in a row ?