Congratuations to me! Wahoo!!!
 

Well, I did it. With my 27 year old Honda Civic hatchback I drove 501.8 miles with one tank of gas. I normally refuel at 450 miles.

I averaged 48.92 MPG in a city / highway driving environment. I normally average 44 MPG. I had enough fuel left over that I might have been able to go 600 miles on one tank.

My changes? I applied super aggressive EOC, which was inspired by the words of someone on this forum who said, "When I'm not pressing the gas pedal the engine is off." I was fairly aggressive before, but now I was following that advice as strictly as possible.

On one straight, 7 mile road through an industrial area the speed limit is 35mph. I accelerate up to 40mph then turn the engine off. With cars approaching closed behind, I restart the engine at 20mph. If NO cars behind me, I coast down to 15mph. I probably should coast down to 10mph, which I normally use to clutch start the engine.

At 40mph it's mostly a "rolling resistance game", according to the Cummins Diesel research that I posted months ago.

I'm ALSO driving 50mph on the freeway. Surprisingly, I haven't gotten any memorable pushback from other drivers for driving this slowly. I suspect my driving such an old car buys me a lot of forgiveness. Driving a newer sports car at 50mph and hugging the fog line would likely draw a lot of gun shots.

With no cars immediately behind me, I even EOC on the freeway on downward slopes.

So, use the Happy Birthday melody and sing "Congratulations to Doug"!

Doug :)
Oakland, CA

Pretty good going Doug, well done. It's easy enough to get great mileage on quick trips here and there, but to average good economy over an entire tank is a different game altogether. Weather, traffic and road conditions will vary hugely over a tank, not to mention the type of journies etc too. I usually loose patience when hypermiling and convince myself it's not worth it ultimately ;)

How much fuel can you Hold? Since I had my Clio, I've averaged over 700 miles per tank, my best was 773 ish. I do like to squeeze in as much fuel as I can, and I'm also willing to let it run extremely low too. But having a good tank range can be a flaw too, the longer the fuel lasts, the more short trips you are likely to take. It's been well over a month since I refuelled, over here it's hard to do a 700 mile journey without running out of country to drive on!

It's a shame you are forced to take such extreme measures to get good mileage though, I appreciate it's an old car, but a modern car would do this without trying. If I lived closer, I'd love to lend you my car for a week and see what kind of mileage you could get, you seem to have a good technique now ;)

773 miles on ONE tank? HOLY SMOKES, Paul!!! (throwing arms in air)

I believe my Honda holds 12.1 US gallons, which is why I'm guessing I can get 600 miles on one tank with "fumes" to spare. :)

Which part of the UK are you living, Paul? For free use of a car for a day, it may be worth booking a flight. I can NEVER pass up a good deal!

Speaking of weather... I was thinking of coming up with a way to monitor ACTUAL wind resistance, so I can drive the car per wind resistance rather than speed. If I have a tailwind, I can drive faster without a fuel penalty. If I have a headwind, I will know to slow down to avoid the penalty. Thoughts?

Doug in California

Yes, although if I drove nice and steady on the highway long enough, I'd get close to 900 miles, maybe even more? Who knows. 12 US gallons is about 10 UK, but they always hold way more. Mine is rated the same size, but as I let it go so low, and top it right up, I can actually get another 10 litres in almost, so another 2 to 3 gallons. I live in Wales, see it says under my Avatar on the left ;)

Wind resistance idea sounds good, hard to measure in a moving vehicle though, you'd have to place the sensor in a wind void, like behind a side mirror or behind the car maybe?

It's 885 miles to cross Texas. There's a saying "The sun has riz. The sun has set. And here I is. In Texas yet." You can drive 885 miles all in Texas or you can drive 895 miles from Charlotte, NC to Wells, ME. driving in 11 states total.

A challenge for you then perhaps? Should be easy to do that on a tank in the Prius no? :)

Congratulations! Gee.... I can't imagine going that far to gain mileage.

I'm 120 miles in. I don't think I could get nearly that much out of a tank. I doubt I'd have the patience to try it either, especially if I was going west as it can be a LONG way between services.

Thanks for the chuckle. Never heard that before.

That reminded me about when I left Temple, TX to return to California. I originally took the train to Texas and bought a used car after I arrived, so I had no idea about the size of Texas.

When driving back to California, it took me two days to cross the Texas border. It drove me crazy, because I felt like I was making zero progress.

You have the same sized tank as me, you'd have to average 60 US MPG to make the challenge possible ;)