Fuel brand quality - Smart Car of America Forums : Smart Car Forum

helidrvr · 10-09-2008, 07:26 AM

Something highly curious has come to my attention over the last couple of months. While this is not a "smart issue" on it's own, it is nevertheless significant to us all.

1. I have a Scan Gauge II and for months have been monitoring both real time mileage (RTM) and (tank) average mileage (AM), mostly out of curiosity.

2. I drive the same route to and from my office every week day and use the smart for local shopping etc. on weekends. No significant fluctuations there. I fill up with high octane all the time. I use the RTM mostly to learn how drivng style can influence it.

3. Generally my AM has been around 37.5 - 39.0 MPG. About nominal for my (suburban) driving environment. Every now and then however, I will get a tank which gives me 42.0 - 43.5 MPG.

Finally, I picked up on the one matching variable: Fuel brand.

All low mileage cycles have been on "no-name" fuel (MARATHON).
All high mileage cycles have been on premium brand fuel (SHELL).

Has anybody other ScanGauge II user looked at this?

BigWarpGuy · 10-09-2008, 07:31 AM

I do not have a scangauge but it does show the old adage; you get what you pay for. In my area, Shell has the higher gas prices.

Old smart · 10-09-2008, 07:53 AM

There has been a lot of comment in the considerable past in one of the big UK forums about the noticed difference in fuel brands - there seems to be truth in it. Marathon isn't exactly a "no-name" (they refine their own products in a number U.S. of locations), but their formulation may vary from Shell's as long at it meets industry and governmental specifications.

Shell is a Top Tier Gasoline; Marathon isn't.

helidrvr · 10-09-2008, 07:59 AM

Turns out that the Top Tier brand is no more expensive per mile than the "cheaper" brands.

SHELL it is for me from here on out!

forestacademy · 10-09-2008, 08:03 AM

Have you checked to see if the premium at Marathon includes any ethanol?

Around here most premium gas does not include ethanol but the other two grades do. Every now and then I find Premium that includes ethanol and will cut mileage.

**jediknight36** · 10-09-2008, 08:16 AM

Quote:

Originally Posted by helidrvr

Something highly curious has come to my attention over the last couple of months. While this is not a "smart issue" on it's own, it is nevertheless significant to us all.

1. I have a Scan Gauge II and for months have been monitoring both real time mileage (RTM) and (tank) average mileage (AM), mostly out of curiosity.

2. I drive the same route to and from my office every week day and use the smart for local shopping etc. on weekends. No significant fluctuations there. I fill up with high octane all the time. I use the RTM mostly to learn how drivng style can influence it.

3. Generally my AM has been around 37.5 - 39.0 MPG. About nominal for my (suburban) driving environment. Every now and then however, I will get a tank which gives me 42.0 - 43.5 MPG.

Finally, I picked up on the one matching variable: Fuel brand.

All low mileage cycles have been on "no-name" fuel (MARATHON).
All high mileage cycles have been on premium brand fuel (SHELL).

Has anybody other ScanGauge II user looked at this?

Quote:

Originally Posted by helidrvr

Turns out that the Top Tier brand is no more expensive per mile than the "cheaper" brands.

SHELL it is for me from here on out!

Ethenol plays a huge part of it, but Shell's premium as a really good detergent in it. So does Chevron/Texaco. Ford and GM both import Chevron from the south when they test MPGs for the EPA and for Emissions. Thats because Chevron (who owns Texaco now) adds Tecron to their fuel. You can buy it at Autozone too, but its "free" at the station. You pay a bit more, but it really does improve mileage. Shell tends to be a but higher than Chevron but if you have one and not the other go for it. It will benefit you in the long run.

**jwight** · 10-09-2008, 08:18 AM

Here's my question: the Top Tier designation seems totally related to the additive (detergent) packages in these brands. Since all of our smart engines are relatively low mileage at this point, it's unlikely using some "inferior" gas would have built up enough deposits that it would impact mpg. And if so, switching to Top Tier gas would not immediately result in better mpg.

So, what's the advantage, if any? Octane is octane (unless ethanol is added, in which case we get lower mpg, not higher) and unless there's some other hidden factor here I'm not clear on why using a Top Tier gas equals higher mpg.

**jediknight36** · 10-09-2008, 08:21 AM

Quote:

Originally Posted by jwight

More on Top Tier gas: Top Tier Gasoline

Here's my question: the Top Tier designation seems totally related to the additive (detergent) packages in these brands. Since all of our smart engines are relatively low mileage at this point, it's unlikely using some "inferior" gas would have built up enough deposits that it would impact mpg. And if so, switching to Top Tier gas would not immediately result in better mpg.

So, what's the advantage, if any? Octane is octane (unless ethanol is added, in which case we get lower mpg, not higher) and unless there's some other hidden factor here I'm not clear on why using a Top Tier gas equals higher mpg.

Not all top teir does. QT is top Teir and I have seen peoples engines blow using QT, which is why they have to guarantee the fuel now. Fuel deposits can build as quickly as one tank from what I understand. If Im wrong, then all I know is that it does help. Go fig!

BigWarpGuy · 10-09-2008, 08:23 AM

I will try either Shell or Chevron if available. Thank you for the recomendation.

**jediknight36** · 10-09-2008, 08:28 AM

Quote:

Originally Posted by BigWarpGuy

I will try either Shell or Chevron if available. Thank you for the recomendation.

if not, go to Autozone and buy some tecron. Its usually in a black bottle with the Chevron logo on it. Not only do I recommend it, but our service dept at Toyota of Lewisville does too.

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