Mpg Difference Between Different Filling Stations

[kc5deb]

I've got a weird question that really doesn't fit anywhere, so, might as well ask it here. I have an 02 2500 with the 6.0L. From the time I bought it till a few weeks ago, I bought gas a supermarket's pumps, normally 86 octane, and no matter what, I've gotten on average 11-12mpg.

 

A few weeks ago, my dad borrowed my truck while his was in the shop, and he put a full tank of gas from a conoco station, 86 octane as well.

 

On my next fill up at the supermarket pumps, I thought I had misfigured something, because no matter how I figured it, I got 15mpg out of that conoco station tank of gas. I fill up with my normal gas as usual.

 

The fuel gage goes down faster (as normal), but, this time I decide to fill up at the conoco station this time. Again, the supermarket pump gas showed that I got my normal 11mpg.

 

The next time I fueled was a few days ago, and I swear, the conoco tank showed 15mpg...

 

I'm absolutely stumped... How could one station's 86 octane fuel produce nearly 4mpg MORE than another's 86 octane fuel?

 

I've been traveling out of town these last few days, and I've filled up twice with other brands of fuel, and the lowest I've got is 14mpg, with the highest being around 16mpg (mainly highway miles).

 

Here's the other catch... I travel a lot to a town about 80 miles from here to get my son every other weekend. When I fill up in that town, I fuel up at the same supermarket chain's gas pumps in that town..

 

I'm going to continue to use the conoco pumps to see if I get a constant 14-16mpg opposed to the supermarket gas.

 

Has anyone else seen anything similar?

[sillyazz]

I've got a weird question that really doesn't fit anywhere, so, might as well ask it here. I have an 02 2500 with the 6.0L. From the time I bought it till a few weeks ago, I bought gas a supermarket's pumps, normally 86 octane, and no matter what, I've gotten on average 11-12mpg.

 

A few weeks ago, my dad borrowed my truck while his was in the shop, and he put a full tank of gas from a conoco station, 86 octane as well.

 

On my next fill up at the supermarket pumps, I thought I had misfigured something, because no matter how I figured it, I got 15mpg out of that conoco station tank of gas. I fill up with my normal gas as usual.

 

The fuel gage goes down faster (as normal), but, this time I decide to fill up at the conoco station this time. Again, the supermarket pump gas showed that I got my normal 11mpg.

 

The next time I fueled was a few days ago, and I swear, the conoco tank showed 15mpg...

 

I'm absolutely stumped... How could one station's 86 octane fuel produce nearly 4mpg MORE than another's 86 octane fuel?

 

I've been traveling out of town these last few days, and I've filled up twice with other brands of fuel, and the lowest I've got is 14mpg, with the highest being around 16mpg (mainly highway miles).

 

Here's the other catch... I travel a lot to a town about 80 miles from here to get my son every other weekend. When I fill up in that town, I fuel up at the same supermarket chain's gas pumps in that town..

 

I'm going to continue to use the conoco pumps to see if I get a constant 14-16mpg opposed to the supermarket gas.

 

Has anyone else seen anything similar?

 

Yes my truck does not like Chevron gas , its either Exxon or Shell that gets the best mileage. I think they put different things in there gas.

[Norseman]

All I run is Conoco gas. The truck seems to run better on it. WHY?? Who the hell knows, it just does.

[nbscanuck]

Not all gasolines are created equal. Even though they both say 86 octane, their are different amount of detergents and other substances that make the difference.

 

I have a Diablosport programmer and I can watch the performance of the engine live (mainly knock for this subject). It does change from gas station to gas station, even tank to tank from the same station. I guess there is even difference in the batch of fuel in their big tanks.

 

If the Conoco is the same price as the supermarket (even a little higher), I'd be buying Conoco. It might pay to try a few tanks of some other brands to see if there is a difference.

[waterman]

if ethanol is the additive of choice, your fuel consumption, maybe be increased up to 10%

[SKYrado03]

if ethanol is the additive of choice, your fuel consumption, maybe be increased up to 10%

I can't buy that.

My 03 4.8L, hates ethanol, would only average 10-12mpg.

 

Since going back to Shell 87octane my milage is up above 15 (see sig), and seems to be going higher. An increase of 33%

 

Are there any members that work in GM assembly plants, here? Maybe you can answer this.

 

I feel that vehicle manufacturer's tune their vehicle's for the vehicle's destination point.

Mine was made at the Fort Wayne, Indiana plant, but sent to Pa., therefore a tune that fits Pa.'s general driving conditions.

Like the oil companies formulate their fuel for different sections of the Country.

 

And to answer the OP, yes, I also have experienced differences between different oil/fuel companies.

[waterman]

if ethanol is the additive of choice, your fuel consumption, maybe be increased up to 10%

I can't buy that.

My 03 4.8L, hates ethanol, would only average 10-12mpg.

 

Since going back to Shell 87octane my milage is up above 15 (see sig), and seems to be going higher. An increase of 33%

 

Are there any members that work in GM assembly plants, here? Maybe you can answer this.

 

I feel that vehicle manufacturer's tune their vehicle's for the vehicle's destination point.

Mine was made at the Fort Wayne, Indiana plant, but sent to Pa., therefore a tune that fits Pa.'s general driving conditions.

Like the oil companies formulate their fuel for different sections of the Country.

 

And to answer the OP, yes, I also have experienced differences between different oil/fuel companies.

 

 

 

i stand corrected. 10% was a number that i experienced, i was merely suggesting that perhaps this could explain the discrepency the OP reorted. actually sounds like his numbers were closer to yours.

[The Factory Man]

<br />

if ethanol is the additive of choice, your fuel consumption, maybe be increased up to 10%

<br />I can't buy that.<br />My 03 4.8L, hates ethanol, would only average 10-12mpg.<br /><br />Since going back to Shell 87octane my milage is up above 15 <font size="1">(see sig)</font>, and seems to be going higher. An increase of 33%<br /><br />Are there any members that work in GM assembly plants, here? Maybe you can answer this.<br /><br />I feel that vehicle manufacturer's tune their vehicle's for the vehicle's destination point.<br />Mine was made at the Fort Wayne, Indiana plant, but sent to Pa., therefore a tune that fits Pa.'s general driving conditions.<br />Like the oil companies formulate their fuel for different sections of the Country. <br /><br />And to answer the OP, yes, I also have experienced differences between different oil/fuel companies.<br /><br /><br /><br /><br />

 

GM does not tune their vehicles for differant areas of the country, unless of course we are dealing with emissions requirements that are differant than federal requirements. FYI, some gasolines have improved additive packages to keep the injection system, valves and combustion chambers clean and these are called Top Tier Gas and the stations selling it can be found at the link I attached. I wouldn't run that discount gas found at many gas stations. I have seen Top Tier Gas clean up some pretty dirty systems.

 

http://toptiergas.com/

[SKYrado03]

GM does not tune their vehicles for differant areas of the country, unless of course we are dealing with emissions requirements that are differant than federal requirements. FYI, some gasolines have improved additive packages to keep the injection system, valves and combustion chambers clean and these are called Top Tier Gas and the stations selling it can be found at the link I attached. I wouldn't run that discount gas found at many gas stations. I have seen Top Tier Gas clean up some pretty dirty systems.

 

http://toptiergas.com/

Thanks for clearing that up for me

[SKYrado03]

i stand corrected. 10% was a number that i experienced, i was merely suggesting that perhaps this could explain the discrepency the OP reorted. actually sounds like his numbers were closer to yours.

Not a problem...At times, the pen is mightier than the sword.

[waterman]

Don't you hate it when you post to a thread and the op never tells you if what you theorized was correct?

[alvocado]

<br />

if ethanol is the additive of choice, your fuel consumption, maybe be increased up to 10%

<br />I can't buy that.<br />My 03 4.8L, hates ethanol, would only average 10-12mpg.<br /><br />Since going back to Shell 87octane my milage is up above 15 <font size="1">(see sig)</font>, and seems to be going higher. An increase of 33%<br /><br />Are there any members that work in GM assembly plants, here? Maybe you can answer this.<br /><br />I feel that vehicle manufacturer's tune their vehicle's for the vehicle's destination point.<br />Mine was made at the Fort Wayne, Indiana plant, but sent to Pa., therefore a tune that fits Pa.'s general driving conditions.<br />Like the oil companies formulate their fuel for different sections of the Country. <br /><br />And to answer the OP, yes, I also have experienced differences between different oil/fuel companies.<br /><br /><br /><br /><br />

 

GM does not tune their vehicles for differant areas of the country, unless of course we are dealing with emissions requirements that are differant than federal requirements. FYI, some gasolines have improved additive packages to keep the injection system, valves and combustion chambers clean and these are called Top Tier Gas and the stations selling it can be found at the link I attached. I wouldn't run that discount gas found at many gas stations. I have seen Top Tier Gas clean up some pretty dirty systems.

 

http://toptiergas.com/

 

 

I've seen this site referenced before but there is no information on who sponsors it, developed the definition of "top tier gas" or how they qualified the recommendations. I personally would not trust something simply because it's on a website. Bare in mind that gasoline is traded and sold as a commodity. That means that refined gas is pulled off the national pipeline system by companies based on schedule and they get whatever refined product is coming through the system, regardless of who refined it. There are specific additives and detergents blended at main terminals which will not noticeably affect things like gas milease assuming you are using the same octane. I've personally watched tanker trucks for small, independent stations fill up at a BP terminal. Major companies sell their products to these jobbers so you aren't necessarily getting low grade gas just because you buy at a lesser known station. You will get differences in the additives which may affect things like carbon build-up, etc. over the long-term as stated above but with regards to the original post, gas mileage should not be affected.

[klunkerbus]

Possibly the supermarket is selling "winter blend" and conoco is not. Even if your area doesn't require winter blend gas, maybe that is what the supermarket is being supplied because that is what their source has available. I've read about people that can tell by a mileage drop when their area switches to a winter blend. I believe most suppliers are using an ethanol blend to meet the winter emissions requirement. I don't know if the winter blend is based on 10% ethanol or perhaps a smaller amount.

[landryd]

I wonder if the accuracy of the supermarket's pumps would have an effect. If you are manually calculating your fuel mileage and taking the number of gallons filled right off the pump, then if the amount of gallons showed is higher than what you really put in would decrease your mileage on paper. It would also benefit the supermarket by charging you more. I'm not accusing anyone of anything, but I would check the calibration tag on the pump.

[FuzzyDriver]

There is another issue that is recently starting to get media attention and might be a factor - hot gas. This ripoff was first reported in the semi-truck circles at truck stops. They found that some vendors were heating the fuel. They buy it cold then expand it with heat. It stays warm underground for a long time, plenty of time to sell it off before it cools off. Hot gas doesn't have as much energy per gallon as cold gas, so your gas mileage (it takes more hot gas to go a mile than cold gas to go the same mile). Next time, see if the hose is warm or your gas tank is warm after you fill up at the station getting you the poor mileage. There is no current law forcing pumps to be temperature compensated in the US, but there is in Canada.