So I'm just simply curious about this. I buy the cheapest 7 11 gas to put it in my jeep I don't know I'm not too impressed with the mileage I get out of a tank, so does more high quality gas like shell for example really effect your gas mileage that much?

 

Theoretically, no. If 7/11 gas has an octane rating of 87, and Shell gas has an octane rating of 87, you shouldn't notice a difference; however, I have had experiences with "bad gas" causing engine stumbles and such. As far as fuel mileage is concerned, if you buy premium, you will most likely notice a fuel economy increase, because where I live, pretty much all "regular" gas has approximately 10% ethanol in it, but most premium gas is still ethanol free. Because ethanol has a lower energy density than octane and all of the other main hydrocarbons in gasoline, you essentially get less energy-per-gallon than using straight gas. If you are lucky enough to live where you can buy regular grade ethanol free gas, you will see a fuel economy increase. (Most people probably aren't willing to splurge on premium for their Jeep Cherokee, haha)

Also, winter blend fuel, which you are probably using now, can detract from fuel economy.

 

You get what you pay for. I know for a FACT that using cheap gas creates all kinds of problems you wouldn't believe. Poor fuel mileage is the least of your problems when you use this stuff.

I once saw a memo my Uncle produced, issued by his employer that demanded employees discontinue buying Arco gasoline for their company vehicles. They were tired of replacing catalytic converters that were being destroyed by the low-quality fractions and high detergent levels. I haven't used Arco since the 70's, because Arco fuels consistently destroyed fuel pumps, carburetors, spark plugs and rusted out the fuel lines. It took a while to figure out the cause, and after I switched fuels, the problems ceased altogether.

We nearly failed our smog check in CA a few years ago because of cheap, junk fuel bought from a discount USA station. The numbers were astronomical, and an investigation revealed that nothing was wrong mechanically with the Jeep; it was the cheap fractions used in the fuel that caused the high numbers. I was surprised to find that cheap fuel could cause smog check problems.

Worse, one of those fractions now is alcohol, which is mostly water, that easily damages fuel system components. Another cheap, waste-product fraction recently discontinued was MTBE, which was highly poisonous as well. I'm sure there are other waste products (aka "additive packages" or "detergents") shoved into cheap gasoline that we don't know about. Those who claim that all gasolines are all the same are flat-out wrong, and should be ignored.

My advice: steer clear of El Cheapo filling stations altogether. They're bad business.

 

I live in OK so about half of the gas stations offer, ethanol free gas. So it would be in my best interest to start putting that in my jeep opposed to E10 which I use now?

 

All gas comes from the same place. It is a commodity sold on the open market and delivered by the same pipeline. The buyer has the option of putting additives in at the tank farm,tanker truck or in some cases the additives are added by the truck driver at the point of delivery. The tank farm close to where I live delivers to multiple brand stations from the same truck.

 

Correct on the point that all (most) gas comes from the same place. I had a job at a fueling station, you saw every name brand tanker pulling in there & filling up, just watch the Indian Res. I've heard baddddd things about them...

I do notice a mpg differance in my DD VW Jetta. I crunched the numbers & filled up with regular & then with Special (middle grade 89 octane i think) and it ended up costing me more to fill, but i got more miles out of the tank. Ended up It actually cost me less to use Special than the low grade because i got more MPG's out of the tank... Work pays me for my milage so i put more cash in my pocket if i get better MPG's...

 

Very possibly. There seems to be a spread overall in reported results in the ethanol vs non-ethanol. For these Jeeps most people have good luck with real gasoline. Ironically, straight as is better for than the environment than ethanol.

In terms of gas being the same, the fuel itself only comes from a few key places. The big difference is in the additive packages that keep the engine clean, and other goodies to make it run nicely. This of course assumes a single distribution hub and refining facility and that storage is the same.

My personal recommendation is fuel from one of these guys: http://www.toptiergas.com/retailers.html If you can find ethanol-free versions of those you should be winning. At the end of the day though it's almost like engine oil. Go with what the Jeep likes!

 

Last time I went down to Tulsa for a weekend I couldnt find a single station that even had ethanol and there were several that had a big sign stating "NO ETHANOL SOLD HERE". Being from KS where corn is a big deal(not as much as wheat) it was rather strange to see so I filled up with non-ethanol fuel and it made a huge difference on the return trip. I was in a '80 cressida 2.6L efi auto. normally averaged 25mpg hwy and 22 city on e10. ac on it would drop almost 2mpg both city/hwy. return trip home with ac running it pulled off a whopping 28mpg...with the ac going.
goes to show that...
If your jeep was brought into this world before the ethanol times it will undoubtedly run better on regular fuel. i have heard of pumps and fuel lines getting eaten alive by the e10 fuel and e85 is even worse

 

i was wondering about this also

gonna test it out for myself and post the results here soon.. I allready know what my XJ does on 87 gonna try 91.