Guest Blogger: Chris Allen on Real-Time Fuel Economy

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We came across Chris Allen’s blog posts a few months ago and loved his statistics-centered style of blog posts. We asked if he would be interested in writing a guest blog post for Leith Honda, and he agreed! We definitely recommend you check out his blog when you have a moment.





I’ve had a month to play around with the real time fuel economy data my car gives me while I’m driving. This is the first time I’ve owned a car with real time fuel economy stats, so it’s been fun! It’s also been educational.

Although, really, we all know how to save fuel already, right? Especially if you watch MythBusters.

– No hard acceleration
– Let off the gas early coming to stop signs / stop lights and coast
– If you’re comfortable without the air conditioner, don’t use it
– The slower you drive on the freeway, the better
– Plus countless other little things

The Wikipedia article on this topic is pretty thorough, and there are lots of fuel saving tips out there on the internet. But most of them don’t really say what is most important. Now that I have real time fuel telemetry, I can put all of these things to the test and see how much of a difference they make.

Minimizing stops is key. When do you use the most fuel? When accelerating from a stop. It doesn’t matter how easy you are on the accelerator, either. Minimizing the number of times your car stops probably makes the most difference in terms of how much fuel you use, especially for shorter trips. (But, be responsible, of course. I don’t suggest running red lights, for instance.) Now knowing how much of a difference this makes, I’ve adjusted my route home from work so that I have one fewer stop sign to contend with, even though it’s a slightly longer route.

By the way, the telemetry reports miles per gallon, but just as useful to me – perhaps more useful in some cases – would be “total fuel consumption” during a single trip, in terms of number of gallons. Because sure, I can get a higher MPG number on that longer route. But since a longer route means more miles, do I end up using more fuel anyway? I guess I could figure that out on my own. Hmm…

Easy acceleration makes a difference, but also watch for “unnecessary acceleration”. That is, let’s say the speed limit on a road is 45 mph, and you know there’s a stop sign a few tenths of a mile ahead. If you’re not already at speed, speeding up to 45 mph only to have to brake for the stop sign a few seconds later wastes fuel, compared to only speeding up to, say, 35 mph and coasting to the stop sign instead.

This saves the brakes, too. My previous car made it to 125,000 miles without ever having to replace the brakes, even though I was originally told I would have to replace them at 80,000 miles. I’ll never understand people who speed up right before a red light.

70+ mph is not fuel efficient. Everyone knows you can save fuel traveling 65 mph instead. But how much? According to my telemetry, the difference between 60 mph and 70 mph is as much as 6 mpg, more so at even higher speeds. That’s a big difference! This will vary from car to car, of course. Personally, I think that when I’m driving to, say, Florida, the time I save over a long drive is worth the hit I take on MPG by not driving slowly. But when only driving from Durham to Cary on I-40, for instance, it’s not worth taking such a huge MPG hit just to get there 1 minute faster.

On many trips, your fuel economy will be out of your control anyway. The fact is, on most shorter drives, what MPG you end up with is more dictated by driving conditions – traffic lights, hills, etc – than your driving habits. No matter how hard you try, you’re not going to get good fuel economy if you’re hitting lots of red lights, for instance. But, good driving habits can help.

How accurate is my car’s fuel economy data, anyway? Actually, the jury is still out. According to the telemetry, I got around 29 mpg on my first tank of fuel. But when I filled the car up for the first time, my calculator actually told me I got closer to 24 mpg. I won’t read into that too much yet, because I don’t think my car had a completely full tank of gas when I drove it off the lot. The day I bought the car, the salesman spent about 20 minutes in the parking lot with me, with the car running, with the air conditioner on, showing me around the car. Not to mention, who knows how full it was prior to then? And I only reset my trip odometer upon driving it off the lot, so any fuel used prior to then (which may have been just enough so that the fuel gauge was still on “F”, but only just) wasn’t factored in. Next time I refuel, we’ll have a better idea of how accurate the telemetry is. One month in, I still only have 500 miles on the car, and it will likely be another two or three weeks before I need to refuel again.

Speaking of which, having a 16 gallon fuel tank is nice, but there’s a bit more sticker shock at the fuel pump compared to only having an 11.5 gallon fuel tank.

But hey, at least I don’t need premium fuel! Used to be, “Plus” gasoline (89 octane) cost 10¢/gallon more, and “Premium” (91 or 93 octane) cost an additional 10¢/gallon on top of Plus. Now it’s a bit more staggered: $3.60/gallon for Regular might mean $3.85 for Plus and $4.10 for Premium. Those extra half-dollars add up! So, basically, be advised if you’re thinking about buying a car that takes premium fuel. (Which, usually premium fuel cars are more expensive anyway because they make more horsepower, which means that MPG is also less than in a more standard car, so…I guess what I’m trying to say is, if you’re considering buying a car that takes premium fuel, perhaps fuel economy isn’t really a concern of yours to begin with.)


Chris is a resident of Durham, having moved to the Triangle from Jacksonville, Fla., in 2006. He is an avid traveler who has visited all 50 states, almost all of which he has chosen to drive to rather than fly, even driving his Honda Civic all the way to Alaska and back in 2010. He also obsessively keeps statistics related to all of his various road trips. When he’s not traveling with his family, he can often be found riding his bicycle or at the Triangle Curling Club. His blog is “The Spectacularly Mediocre.”

Guest Blogger: Chris Allen on Real-Time Fuel Economy was last modified: December 30th, 2014 by Leith Honda

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