Yep, we all are doing better than a non-hybrid would do. I just like obsessing and it is nice to do it here where everyone is so helpful and patient

 

Another thing that can affect gas mileage is a seasonal change in the fuel additives. I don't know how it is in the rest of the country, but Maryland changes its gasoline formulation during the winter months. In theory the "winter gas" formula is supposed to reduce air pollution (it doesn't, but the chemical factory that makes the additive contributed heavily to one of our past Governor's re-election campaign. Go figure).

Anyway... this "winter gas" makes my HCH get about 42 MPG, while the "standard gas" yeilds about 45 MPG.

 

I'm not an Erlich fan necessarily, but it's got nothing to do with his campaign. The EPA mandated with the Clean Air Act, and year-round RFG in 95.

The winter oxygenating program has largely given way to year-round oxygenation in RFG, MD (Baltimore specifically was on the targt list) included. We have 10% MTBE in our fuel all year long, so that is not causing the delta you see. Pre-95 MD gas was only oxygenated in the winter.

Oxygenating fuel DOES definitely reduce CO emissions, which are not only toxic but serve as a precursor catalyst to ozone formation. There is no rational debate anywhere about this. The debate is over the "weekend effect" (http://www.osti.gov/fcvt/deer2002/lawson.pdf) and what additive is used- MTBE, ETBE, or ethanol. MTBE is carcinogenic, ETBE is hardly made, ethanol kills mileage. Pick your poison. (Now THERE is where you might find some campaign contribution cannon fodder.)

But there are still seasonal differences in RFG not related to oxygenation or CO production:
Winter RFG has higher vapor pressure, which means literally lighter molecules with fewer chemical bonds, which means less energy per gallon, about 2%. Being easier to evaporate makes it easier to start your car in the morning. Summer gas is required to have lower RVP to mitigate evaporative hydrocarbon emissions. They are also ozone precursors. If anything, SUMMER gas is the more 'eco-friendly' fuel for those with year-round oxygenation.

http://www.epa.gov/otaq/gasoline.htm to find out the specifics for your locale, and historical information from 1995 on.

Most high-population areas are all under the same program, or even stricter local codes.

 

10% of leakage??? It's huge!
Maybe, it is true among GM or Ford parts.
But, it should be defective if you saw such huge leakage. The ICE will be over cooled.

Ken@Japan

 

It's not leakage they (at least some cars) are designed that way. Think about it - do you want to have the thermostat pop open when the engine coolant is 180*F and suddenly blast in a radiator full of 0*F coolant? I know even the opening mechanism isn't a "pop" open for thermostats, they are more of a progressive mechanism; the higher the temp, the more it opens up. I'm pretty sure all are designed so even in the closed position there is a small amount of circulation to the radiator. I'll do some checking around and see what I can turn up on the subject.

 

I had a Ford full-size van that had a thermostat get stuck about 10% open and it never warmed up like that. Thermostats should be sealed shut until they reach a certain temp where they begin to open.

 

That's for sure. I've been consistently getting around 51 MPG on my 29 mile commute with morning temps around 40. I decided to see how much the cold starts were affecting my trip mileage, so I reset the trip 10 miles into my commute and got 62 MPG on the remaining 18 miles.

I can't wait to see what happens when it warms up!

 

Well, I have hit an all time low. During the fall I was getting 50 mpg. The temps have dropped to around freezing, roads are dry, but my mileage is 38 mpg. I was really hoping for a lot better

 

It took a winter storm in Dallas to realize this: if the roads are iced over, you can't safely cruise at a fuel-efficient 40mph. With the possible exception of the freeways, you can't go above 20mph if you want to stop in time. On freeways, bridges and mixmasters are frozen, and there is more traffic.

 

me obsessing??? who you calling obsessive????

as hard as i try, i still want the best of both worlds, the FE and the safety. and on the backroads home last night, i managed to eke out 55jpg again, only to lose it getting back to the 4 lane this morning. not to mention, i washed the car, and the truck was about frozen shut when i got home.......the joys of a minnesota winter. the car's either dirty or frozen.

and i do consider that we are still getting better than about 90 percent of the speeding truck jockeys that roar past us, with obvious disgust for our lowly vehicle and turtle like pace.