Easy question - MPG

So, I took my completed car out for a decent drive, about 20 miles. Lotta traffic so I sat at some lights, a little stop-and-go, and when on the freeway (about half the miles) never got over about 55mph. Didn't go overboard on trying to maximize MPG, but did keep my foot out of it for the most part. I averaged 55.1 mpg.

I seem to recall when I last drove a good running Gen 1 that the mpg seemed to get better around 70mph, at least by the running average. Does that sound right to y'all? I'm tickled with 55mpg - my truck gets 9-10 and my Camry gets in the low 30s, I think (never tried to get an accurate measurement).

 

That's what I used to get the last time I had one of my cars running. From reading here, it seems that as the battery fades, the mpg decreases. This car has the freshly rebuilt battery. But, again, small sample size, but I tried to get a variety of driving conditions. Should have two more of my cars ready shortly, both with older batteries; we'll see how they do. I just wondering what this one would do going 70mph out on the open highway.

 

Thanks, WHCSC, I didn't know where the 70 number was coming from.

But no one is answering my question - do you see better mileage driving 55mph or 70mph? Common sense says 55, but sometimes the gear ratios in the transmission (old cars in the rear differential) can have a higher "sweet spot." Just recall before my first Gen1 seeing higher numbers on my screen at 70, but it might have just been some coasting/foot off the gas involved.

During my test yesterday, I'd say that most of the time, I was around 52-53, but when I pulled in the driveway, I was at 55.

 

I bought my first Gen 1 in from a lady in Chicago who was moving to NYC and wouldn't need a car. Had less than 20k miles, but it had been totaled in a wreck and had a salvage title. Couldn't tell at all by looking or driving it. I flew up there and drove it back to Dallas, cost me less than $30 in gas. I was amazed. It was my daughter's graduation present and we still had it in the family until a couple of years ago when a nice couple bought it for their daughter's graduation.

Funny, it had recurring instances of the orange triangle. In hindsight, I'm sure it was the HV battery, but the local dealers knew nothing about it. However, because of the salvage title, it was no longer under warranty. That didn't occur to me...or the dealers since it was so new. Had three different ones service it - not sure what they did, but the triangle would go out for a few months - before realizing that it wasn't warranty work, and then didn't charge me since they told me it wouldn't cost anything, lol. The battery finally died, and rather than pay $5k for a new one, I parked it for several years. Later got a Dorman battery for $1800 installed by Chris Auto in Dallas (great guy and member here), and drove it a few more years before selling it with about 180k miles.

Funniest story was the first time I took it to be inspected, and they guy didn't know what to do with it since the engine cut off and he couldn't get a required exhaust test. He'd never heard of such a thing, but finally concluded that it probably passed.

 

Thanks, Mendel. Makes complete sense. I wonder how accurate the mpg gauge on these cars are. I know they're pretty useless on a lot of cars, more like the tall bar graph on ours that provides the "instant" mpg. I've never done a true test by filling up and dividing miles by gallons. Probably because...why care, lol? At this mileage rate, it's all good.

 

IMHO, anything over 50mpg makes me notice. Under that, not so much, although still good. Mktg probably trying to get to that "take notice" level.

Just got back from another 15 miles, hardly any of it freeway and the whole time with the AC on (rainy cool yesterday), so it kept running at traffic signals. Now, my cumulative mileage is down to 45.

 

Yes, I'm sure that's true, but again, with the exception that gear ratios can make a difference. I have both an F450 truck and an F350. Same engine, trans, body, and interiors, and yes, the 450 has heavier axles and suspension, but still, at the same RPMs, it also goes considerably slower and, of course, gets less mpg. It also seems, although I've never measured it, to get better mileage once Overdrive kicks in than it does if I leave it in Tow Mode, which doesn't use Overdrive.

 

Cool, that's the answer to my question. My experience of seeing, IIRC, my mpg number go up after accelerating up to 70 from 55 was simply a product of, I expect, me leveling off the pedal once I reached that speed. I.e. we get better mpg while cruising than while accelerating. Just as I'd get worse mileage when slowing down to 55 while going up a hill.

 

Yeah, I've seen the pulse-and-glide effect. Works on the GF too!