Hi All,

I recently got back from a Thanksgiving road trip (NC-IL and back) - a 2000 mile round trip.

The first 2 tanks (NC-IL highway cruising) worked out at 35 mpg.

The third tank was city driving around IL so wouldn't expect as good but came out at a lousy 25 mpg.

The forth tank (first half of return trip IL-NC) was all highway cruising but came out at 30 mpg - way off the mpg for the first 2 tanks (also highway cruising).

The fifth tanks (second half of IL-NC) was highway cruising and came out at 36 mpg.

Clearly there were 'issues' with the forth tank. The only factors I can think of are

1) It was a tad colder
2) There was a bit more of head wind.
3) The tank was filled in IL. This might explain the 5 mpg discrepancy because I noticed the pump mentioned the fuel contained 10% Ethanol.

Would Ethanol have this effect ?

Would all fuel in IL have Ethanol right now (hence also explaining the lower then expected mpg for tank 3) ?

Any other comments ?

 

E10 yields ~3% FE hit relative to pure gas. That's about 1mpg for us. Also, NC may not have winter formulation, depending on where you are? Winter gas takes off another 3-4%.

Yes, IL is an E10 region, at least part of the state. And definitely winter fuel.

Browse here http://www.epa.gov/otaq/gasoline.htm to find out the particulars for your area.

You hit many of the factors that make up the rest, but missed altitude. What was the net change from A to B? Parts of NC are pretty high, relatively speaking.

Did you have more stuff in the trunk (presents, etc)? Grandma tied to the roof Griswold-style?

 

Hi gonavy

I'm in the flat central bit of NC - pretty much the same elevation as our destination in IL. We had to go through the blue ridge mountains (I40 west) which gave a slight net gain in mpg (from start of mountains to the end of the mountains) - maybe not as much as if we had driven the same distance w/o the up/down bits.

Apart from a possible gain in weight from all the turkey consumed (2 occupants), the car was in pretty much the same shape as the outward trip - as "confirmed" by the fifth tank @ 36 mpg (btw: not as good as yours - how do you do that ??? )

The map on the EPA site show none of NC as having reformulated gas (but the part of IL I filled up in *is* reformulated)

How is gas changed for the winter? - I assume "winter gas" is not the same as reformulating with Ethanol (the EPA website leads me to think Ethanol is year-round).

 

Yes, ethanol (or MTBE in most areas) is a year-round additive to reduce CO emission and possibly reduce ground-level ozone (see this bit of controversy: http://www.osti.gov/fcvt/deer2002/lawson.pdf). Both reduce MPGs, but ethanol more so. All RFG fuel is "oxygenated" with MTBE or ethanol to 2% oxygen by voume (that's about 7% ethanol or so). Some areas (IL, IA) use E10 which exceeds this requirement and has higher oxygen content, with correspondingly lower CO and FE.

Benzene and other toxins are lower year-round in RFG as well.

In addition to the year-round RFG requirements there are seasonal ones as well. The biggest difference is in vapor pressure (RVP):
Summer fuel is required to have a lower RVP, to mitigate evaporative emissions caused by higher temps. It is literally heavier, with more chemical bonds in the fuel molecules...more bonds to break = higher energy content = better MPG.

Winter fuel has lower RVP, so it evaporates more easily, is easier to ignite (and start your car when cold), but has lower energy content.

On a related note,
I did an experiment in my HAH with "E33" - 1/3 ethanol, 2/3 winter gas. MPG results were not pretty. 12% hit, even worse in loacl driving. https://www.greenhybrid.com/discuss/...ress.4411.html

OTOH, E85 spits out ~14lb of CO2 per gallon burned; gas spits out ~20lb. Per mile, E85 still spits out about 20, BUT...the CO2 from ethanol was part of a plant just a few months prior, which had sucked in that CO2 a few months before that, as opposed to introducing "new" CO2 that was locked away for millions of years. Now where that E85 comes from is another issue for another thread.

You've shown that you can get good FE- 36 ain't bad going over the Appalachians with a passenger and cargo. I assume you were on CC a lot at 65-70. Getting over EPA is often a function of your personal driving situation and commute/travel route. 80% of my driving is my solo commute, so I can use more techniques than when with my wife, who looks at me funny when I get too green for her taste. So I cave to negative peer pressure. I am weak. (I was able to admit that even without going to therapy!) And I too get 36 or so on hills at 65-70mph with CC on.

 

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That's possibly backed up by the EPA- their surveys indicated ~1% ethanol in sampled NJ areas- an strange number, explained by some stations/chains using it and others not. Also seen in MA and CT and a few others.

HESS also only uses North American-sourced fuels, IIRC. No Osama feeding there.

How did you come across that info? Was it posted on the pump?

 

I've heard that from a friend, too. Does anybody know where I could get actual hard data about the composition of the gasoline from major US vendors? I've been trying to settle an argument with my old college roommate.

 

there was a thread in the forums somewhere that listed the companies that used US-sourced crude, and I think a link too.

Here we go:
http://www.eia.doe.gov/pub/oil_gas/p...mmary2005.html

For the 1st half of 2005, the following companies imported NO cude oil from the Persian Gulf Region (pre-refined products may have come from offshore that were from PG drude, though)

Sunoco (almost all West African)
Shell
Flying J
CITGO imported barely 1%...they are wholly owned by the Venezuelan gov't, which is its own can o' worms.
Some others I didn't recognize, probably wholesalers.

It must be pointed out that even though a company may not import oil from a source, once its refined it all goes to a few terminals for transport through pipeline, where it often does get mixed. Retail gas is a wildcard in most cases.

In 2000, Shell imported a lot from the PG, but BP/Phillips had zero. So it goes with the market. Sunoco is the only company I found no PG imports from, but they get distillates from offshore- no telling their source.

 

That's good to know, since Shell regular seems to make my HAH go best (and, unless I am imagining things, seems to allow for a very slight mpg gain, if that's possible).