San-AnT

So my brother's 06 TSX has been getting really shitty gas milage these last two weeks, down from 31-33 to 21-23. however, the dealer that we both go to has a service manager who tried to tell us that his lower milage is due to gas stations changing to a summer blend.

correct me if i am wrong, but wouldn't a summer blend allow the car to be MORE fuel efficient? btw, we both live in very warm climates. I think this guy is FOS

Corresponding article below (keep in mind that even though it is an old article, it is still relevant):


What Is Summer-Blend Gas?
And if it's so clean, why don't we use it year-round?
By Sam Schechner
Updated Monday, April 12, 2004, at 5:55 PM ET

According to a survey of 8,000 service stations released yesterday, American motorists are paying an average of $1.80 for a gallon of gas. While several factors—including record demand and the unusually high cost of crude oil—account for the increases, news reports also place some blame on shortages caused by the annual switch to smog-reducing "summer blend" gasoline. What is summer-blend gas? And if it's so clean, why don't we use it year-round?

The term "summer blend" is shorthand for a menu of federally and locally mandated summertime fuel recipes that are designed to cut down on smog. The gasoline we use is always refined from an intricate blend of ingredients; the process combines coffee-dark crude oil with various additives that increase performance or make fuel burn more cleanly. Because overlapping federal and local requirements call for different recipes in different locales and seasons, there are approximately 20 distinct "boutique blends" of gasoline sold in the United States. Some Americans end up pumping a blend called Carb (named for the California Air Resources Board) while others burn Atlanta (named for Georgia's capital, where it's sold).

Refineries brew their summer blends by removing hydrocarbons that are more prone to evaporate in hot weather. These chemicals, called volatile organic compounds, react with airborne pollutants in the summer sun to form ozone, one of the main components of smog. From June 1 to Sept. 15, the EPA mandates that pumps in 12 high-ozone urban areas—such as Los Angeles, New York City, and Baton Rouge—deliver gasoline that meets special low-evaporation standards. Several states have voluntarily adopted the rules, and 15 have enacted their own seasonal-blend regulations on top of the EPA's. For example, pollution-conscious California has mandated that service stations must start selling its summer blend in May.

Summer-blend gas isn't new. It was first sold in 1995, as required by the Clean Air Act's 1990 amendments, and the current, even cleaner, concoction was phased in for the summer of 2000. Since then, there have been sharp spikes in fuel prices every spring as summer blends get rolled out. This is not so much because it's expensive to make the gas—the added cost per gallon is only 1 or 2 cents—but because refineries generally try to sell every last bit of winter fuel before mixing in the slightly more expensive summer batch. Sometimes they draw down the stock too far, creating shortages before the first deliveries of summer blend enter the supply chain. The return to normal blends in the fall causes a far less pronounced spike because the industry, free from summer standards, doesn't bother selling off the summer gas before mixing in the less pricey stuff.

So why not use the summer blend year-round? The main reason—apart from the fact that the 1990 law isn't written that way—is that summer-blend gas doesn't work as well in the winter. Summer blend's low-evaporation rate makes engines less likely to stall in hot weather but can make them difficult to start in the cold.

a newer link: http://www.suntimes.com/output/news/...gasside20.html

jpt

There's not nearly enough of a difference between summer and winter gas to lower your mileage by 30%. Has traffic been getting denser? Did your brother's job move closer to his house?

San-AnT

no and no. no major changes at all. that's why we are trying to get a better reason for the drop in mileage

Alin10123

The winter blend is supposed to get you less mileage because of the higher % of additives that they add in there. It's done this way so that your car warms up faster in the winter and doesn't give off as much emmissions. In the summer you shoudl be getitng MUCH better gas mileage. The guy is full of it.
Even if it was true, it wont account for a 30% drop in gas mileage. I'd try a different dealer or something if i were you.
Have oyu checked the simple things yet? Air filter? fluids? tire pressures? alignment? tire wear?

San-AnT

well, his CEL light came on last night. they didn't even bother to check it out, they just gave him excuses. he's going to a different dealer now.

psteng19

It's not due to summer blend.

It's due to the changeover from MTBE to E10 (ethanol).

fuckleberry

wow 2 TSXs in teh family.
Who's your bro here ?


BTW, got the navi mod done. Thanks for everything !

virtualbong

Your bro gets 31-33 mpg??? That's awesome! I do a lot of highway driving and I only get about 26-27 mpg on my 05 auto.

Alin10123

CEL?
dang... that's possibly from a shady gas station. Maybe they put water in their gas. try a different brand of gas from a station that gets a lot of volume to see if things change.

San-AnT

he only uses shell. so do i. anyway, the former mileage is only highway (from houston to san antonio) time, not city driving. that's about what i get on the highway also. it's a 3 hour trip in-between, so few or no stops means more mpg.

San-AnT

he's purplepeopleater. lets see some pics of your mods!!

jpt

Also no.

japhar81

I gotta say I've noticed this too. Same daily commute. Same traffic (none). Same setting on cruise control. First four tanks I was averaging 29-31, the last couple, I'm at 26.5-26.7.. Same two gas stations for all the tanks. I was writing it off as summer blend/E10.. if that's not it, what could it be?

My TSX is brand new still, only 6 weeks old, cant be engine trouble already.

sauceman

So it would probably be an anti-smog part like an O2 sensor that screwed up and is also messing up your mileage, since your ECU has to go in limp mode, making it run very rich and with retard timing.

jpt

San-AnT

i agree with you sauce, but he doesn't think that's it. I told him from day one he probably has a faulty O2 sensor.

sauceman

Yeah, that summer blend thing is pretty retarded. You're supposed to always get much better mileages during summer, due to various factors, one being the air resistance is lower because of lower density, and that same lower density forces the ECU to lean out the mixture as well.

psteng19

Huh???
Are you saying that I'm wrong? That E10 is not hurting gas mileage?

sauceman

I remember having tested with it a few years ago on my Accord and it did negate the mileage by a few mpg. Power seemed also short.

biker

Go to Brazil and see your milage drop a lot because of the amount of ethanol in the gas. The more ethanol in the gas the lower the milage - not to the tune of 30% but it does hurt milage. Vehicles designed for E85 usually have lower milage numbers than the regular gas equivalents of the same car running on just gas.

Assuming the summer blend changes the proportion of ethanol in gas to about 5% of volume, I'd say the milage hit should be on the order of maybe 1-2%.