Different Gas stations affects MPG?

[smay665949]

I was talking with a friend from work about how his car is running poorly. He told me he fills up at Cosco because of the cheaper fuel.

In my area we have Maverick, Flying J, Cosco, Sams, Conoco, Chevron, Citco, Shell Tesoro and Sinclair. My advice to him was to fill up at Chevron, Shell, Citco or Conoco based on my experience with my 2001 Chevy Impala. If I used Maverick, Flying J, Cosco or Sams I would expect about 25-50 miles less on a tank. In addition the car would misfire at idle with this cheaper fuel. I also seemed to get a smoother idling engine running 87 octane accept at Chevron where I could have the same result with 85 octane.

Unfortunately my wife fills up wherever is convenient. She has been driving the car for 3 of the 6 years I have owned it and I have had to replace the fuel filter every year until she got her Jetta TDI. I have also had problems with occasional engine surge that the dealer couldn't isolate that went along with the fuel filter replacements. Surprisingly adding a bottle of Amsoil Performance Improver Fuel Additive at 201,000 miles and the problem has gone away. Needless to say I was totally impressed with the results especially when the instructions on the bottle said to use it every 4000 miles.

Groar, Where do you get different grades of diesel? In my area we have on and off road diesel and Sinclair carries B50 Biodiesel in the summer that runs the same but loses about 30 miles on a tank. Of course we also have winter diesel in the winter that kills economy.
In the summer my 8000 pound 95 Ford F-250 extended cab 4X4 gets consistent 19MPG shifting at 1500-1800 RPM with an occasional jump to 20 when I stay under 65 on the interstate. In the winter it gets 17-18.
I hope to get an extra 100 horsepower, 230 ft pounds of torque and 22+ MPG with an upgraded exhaust turbo and intercooler.

[groar]

Originally Posted by smay665949

Groar, Where do you get different grades of diesel?

In fact the grade diesel may not be the correct term. It's mainly the default additives that make the diesel a low/mid/high grade.

In supermarkets the additives are minimal. They permit to avoid foam when you fill your tank (so they sell you more diesel at each refill), and optionally to mitigate diesel's odor persistence (to make you feel more ecological). Here is low cost, low grade.

In little stations and automatic stations you have a few more additives. Here is mid cost, mid grade. An example is Esso stations.

In stations with services, the additives are more important and should permit you to never have to add additives such as injectors cleaners. These are also compatible with next European norms such as low sulfur (10 ppm due for 2009/01/01). In these stations you have both mid and high grade. Costs are of course mid and high. In France there is only Total, Shell and BP.

Since a few months both my wife and I are using high grade and are seeing a better behavior of our cars. They have always been maintained as constructor's schedule. Now I can accelerate from 1200rpm while I couldn't stay at 1500rpm before that. The "holes at acceleration" disappeared on my wife's car.

Denis.

[bowtieguy]

Originally Posted by smay665949

Surprisingly adding a bottle of Amsoil Performance Improver Fuel Additive at 201,000 miles and the problem has gone away.

i'm going to presume that's not spam. so i'll defend that statement...

a local celebrity mechanic/consumer advocate recommends Amsoil PI as well. he believes it's one of the best fuel additives out there(as most are just a waste of $$$).

i've used it with good results as well. every 4k miles is debateable however. i drive mostly hwy miles, so 6 months or 6k miles works for me. depends on your application certainly.

[Jay2TheRescue]

I'm experimenting with a bottle of BG 44K in the beast's current tank.

-Jay

[GasSavers_GasUser]

Originally Posted by suprapsu

I notice that some different gas stations have different quality gasoline. I know for a fact that with Shell they add a techron additive to premium gasoline. Anyone notice the difference in MPG when using different gas stations?

I own a Supra and I know for a fact that different gasoline affects its performance but I'm not sure about MPG?

Techron is a registered trademark fuel injector/system cleaner owned by Chevron not Shell. So it wouldn't be in Shell gas unless Shell bought out Chevron lock, stock, and barrel, patents and all. It is in all grades of Chevron fuel and is part of Chevron's patented additive package.

Branded gasoline mostly comes out of the same pipeline so it starts out all the same. Then each Brand ads their own additive package to the gas. That is where the difference is. All major brands have their own (secret and patented and hyped up as better than the other guy). Which one is really better?? Who knows.......

As far as non name brand gas goes, you have no idea what you are getting and I am sure there is a difference between that and a branded gasoline. Then, after that, there is probably ethanol in it in areas where both ethanol blended and straight 100% gas is available. Generally, you get what you pay for in quality. (or in the case of gas, what you pay too much for)

Personally, I pretty much stick to name branded gas and avoid the others unless it is an emergency.

[smay665949]

Originally Posted by groar

In fact the grade diesel may not be the correct term. It's mainly the default additives that make the diesel a low/mid/high grade.

With the exception of Chevron diesel is competitively priced here and I can't tell the difference in FE like on my gas cars.

The nice thing about my Ford is the tanks are 16 and 17 gallons so I know if I get 285 or more miles to a tank I am getting right at 19MPG.

I have run fuel additives with no effect on economy. Cetane boost quiets the engine and helps it start better in the cold.

I have read in some of the diesel mags that low sulfur diesel has killed power and economy.

[groar]

Originally Posted by smay665949

Groar, Where do you get different grades of diesel?

In Europe the minimal cetane index is 51. After a little research I found that Total has 52 for its mid-grade and 55 for its high-grade. This index is partly boosted thanks to an additive called procetane. High-grade from Shell and BP also have a cetane index of 52.

I read in some french forums that some third party additives for diesel contain procetane.

Denis.

[jeep45238]

Originally Posted by 1cheap1

I fill up to the top of the filler tube every time so i know it is filled up.

Your EVAP system does not like this one bit. Just an FYI.