I have noticed that on my 2002 Siennaa that it gets around 24 mpg at a steady 70; 26 at a steady 65, and it has 217,000 miles so, yes, I am sure.
There is a state in Mexico where the speed limit on a high speed toll road is around 50 mph. It is actually too small to determine mpg. I have long wondered how efficient it is at a steady 50.
I lose usually one tire a year in Mexico. This year I lost two. Road hazards. So, I bought two local tires, Cooper Classics. He said he balanced them, but when I hit the highway over an hour away (local speed limits are around 38 mph) anything over 50 was clearly out of balance.
So, when I started my 840 mile trip back to the border for my annual visit, I had to keep my speed down to 50. The first fill after 169 miles which included roads so bad I averaged 25 mph for two hours, it came out to 24 mpg, which is pretty high for that hard driving.
The next one was another 387 miles and the fill-up took 43.12 liters, my calculation shows that as 11.391 galllons, = 33.974 mpg at a steady ~50 mph.
Last fill was in the US. Alas, it included around 70 minutes in traffic waiting for immigration, in gear with motor running. Still, it was 286 miles and the fill took 10.371 gallons for that leg. 27.58 mpg.
Total trip was 30.92 mpg.
I don’t know how much gas was used in the waiting on the bridge over the Rio Grande. A half gallon? A gallon? Any ideas at all?
Balancing at Pueblo tires cost $25 and it seems stable now.
Oops! Error. I meant total trip after the first fill was 30.92 mpg, the first 169 miles is so hard I chose to simply exclude it since I was looking for mpg at 50 mph, and that 169 miles was anything but that. Sorry.
Another thought. The usual suspects here agonize about the horrors of interrupting the flow of traffic by driving slowly. In Mexico, drivers are used to that. Big trucks grind along at slow speeds, so all drivers must be truly experienced at traveling through slow traffic. I caused no serious disruption at 50 mph. In fact, it was a peaceful, low stress trip compared to the usual. But, I don’t think I could force myself to drive that slowly without strong motivation such as I had.
And, overall, I don’t think it really took me that much longerr both days than normal. There were plenty of stretches with low speed limits, anyway.
I once read somewhere that a car uses half a gallon of gas per hour to idle. I have no idea how accurate that is.
If I was having that many flat tires in a place that might not fix them correctly, I think I’d keep two more tires mounted and balanced on steel wheels ready to use.
I’m not surprised at your gas mileage. I believe you get the best gas mileage at the slowest speed you can go in the highest gear, which is probably around 45 or 50 MPH for most cars.
We did a number of European holocaust tours with the bus going a max of 50 mph. It was a legal thing to avoid any potential injury liability, the tour organizer required the bus to go that speed. It was not bad at all from a passenger perspective but would have driven me nuts as a driver.
Remember that gasoline crunch we had back in the 1970’s? In response my local high school hosted a student car “race”, held out back on the school 1/4 mile track, and the winner was the car that got the best mpg over a 40 miles run, 160 times around. An energy conservation race. It didn’t matter how fast they drove or how long it took to go 40 miles, just the mpg. That wasn’t the most exciting car race I’ve ever seen – the students who entered found they got the best mpg at about 25 mph. That was one very slow “race”.
Now that I think back, I had to drive every day and it was even/odd license plates so you could only get gas every other day. I kept a couple ten gallon cans of gas in the garage all the time. Taking a 200 mile one way trip to the in-laws required some extra thought lest you get there and not be able to get back. All political, made no sense.
Actually, Lion, I do keep two spares already mounted, except when I went looking for a spare rim, the best deal at the time was an alloy rim, not a steel one. So, I need to keep track of extra nuts and the key to take them off and on. They balanced that one when they put it on the rim. I used it once at the time I had to buy the two new ones.
I think the tire repair shop can fix them okay, but if the sidewall is damaged, he can’t make that go away. I remember some years ago seeing nails in an intersection, and started picking them up. I think I picked up over half a pound of nails in a small area. Later they paved it so they are much easier to see.
Also, that 1/2 gallon per half hour is closer than any idea I had. Thanks. I may hit Google, I have been incredibly busy what with a plan to go back in three weeks.
I think I will run a load test in gear and in neutral, on my live data scanner, not sure if it means anything.