Speed Kills…Your Gas Mileage that is. Hypermiling for Noobies.

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in Frugality,How To...,Trick

On my recent good old fashioned family trip to the Oregon Coast we roadtripped down in our VW SportWagen TDI.  I had hundreds of miles to cover and while on the freeway I figured I’d test out some different techniques to see if I could maximize our already excellent gas mileage. We normally get about 38-40 mpg in our Jetta which is fantastic but I wanted to push it further after being inspired by the TankWars competition on the VW website.  Some TDI drivers claim to be getting upwards of 58 mpg. So what follows is a collection of techniques and their results from my extremely unscientific tests. If you want one theme overall it’s: SLOW DOWN!

Hypermiling Basics

What is hypermiling? Hypermiling is maximizing gas mileage by making fuel-conserving adjustments to your car and driving techniques.   These adjustments might be increasing the air pressure in your tires or at the very least making sure the air pressure is the appropriate level. Or it might be so far as to remove any roof racks or other items on the outside of your vehicle to reduce your wind resistance and increase your car’s aerodynamics. As far as driving techniques go there are a variety of methods you can utilize to conserve fuel:

  • Turn off the Air Conditioner. When you engage the Air Conditioner you put an additional load on the engine beyond the voltage that the Alternator is already providing.
  • Keep your windows rolled up. Hmm what? Turn of the AC and roll up the windows? These are techniques I never said they would be enjoyable. You want to save gas don’t you?
  • Drive smoothly. No sudden accelerations, it’s a mileage killer. Just ease into it, don’t jackrabbit off those starts like you know you do on the way to work.
  • Keep your overall speed down. This one is absolutely huge for all you prospective hypermilers. When you see the speed limit change to 70MPH just ignore it, move over to the slow lane and lock in about 50-55mph. You might want to also turn up your tunes to drown out the swearing and honking from your fellow drivers.
  • Don’t just sit there, get driving. Idling is earning you exactly what you expect 0MPG. If you are going to sit more than 7 seconds it’s recommended to shut off your vehicle.
  • Stay away from hills. This one’s relatively obvious but rather difficult in concept especially if you live around the Northwest where it’s not exactly pancake flat.

If you want an in depth treatise on hypermiling and it’s benefits you’ll want to check out Wayne Gerdes article on his website CleanMPG.com on Beating the EPA – The Why’s and How to Hypermile. Wayne is essentially the father of hypermiling or at least is documented as such from those in the know on the Interwebs.

Hypermiling Explored

Let me first explain that I’m not a hypermiler. I haven’t ever bothered to employ these techniques. I normally commute to work on a motorcycle and it gets roughly 50-60mpg so I feel like I’m doing my part anyways, but I was really curious if these techniques made a big difference and if they were practical.

The Conditions

It’s 1:45PM PST in July cruising southbound on Interstate 5. The air temperature was roughly 87 degrees Fahrenheit. Our vehicle is black. I would not be testing any of the Air Conditioning tests, my crew of 3 passengers would have promptly ended my hypermiling experiments with extreme prejudice. All tests were performed on relatively flat portions of the Interstate in 20 mile increments using cruise control. My car has an advanced computer system that allows me to determine instantaneous miles per gallon as well as average miles per gallon over time. The computer was reset after each test.

Hypermiling Test 1: 70 Miles per Hour

The speed changes about 6 times on the way down to Oregon so I had opportunity to test at multiple speeds. The first was at 70 MPH. The result after 20 miles was 39.6 Miles Per Gallon. That’s certainly nothing to sneeze at but I definitely thought I should be getting better than that. Oh look 60 MPH zone ahead on to test 2.

Hypermiling Test 2: 60 Miles per Hour

Same as before I locked into 60MPH on the cruise control, got over to the right hand lane so I wasn’t run down or forced to slow or speed up and after 20 miles we got a whopping 46.9 Miles Per Gallon. That 10 miles per hour made a large difference. Now on to the most painful of tests (for me anyways).

Hypermiling Test 3: 54 Miles per Hour

I just couldn’t bring myself to drive any slower than this, it’s all I can do to stay out of the left lane as a matter of course but I really wanted to see what the difference would be. All reports say that around 50-55MPH is the sweet spot for your optimum MPG so I gave it a shot. Result:  48.9 MPG. You’ve just got to get over the fact that your under the speed limit. For me it’s nearly impossible to not at least drive the speed limit but if you can you’re going to be rewarded with less time between fill-ups.

Hypermiling Test 4: Drafting

This one was difficult to quantity as your speed will vary depending on how close you are to the vehicle in front of you and how much time you spend explaining yourselves to the authorities or whether you travel in a traditional ambulance or they medi-vac you out of there. This is dangerous folks, no way around it, I tried it for a little bit behind some Semi-Trucks while everyone was drifting off to sleep for some definite gains on the instantaneous MPG meter. I was seeing upwards of 75MPG at times but I only did this in short bursts and thought better of it.

Hypermiling Practicality

So after all these tests have I drastically modified my driving style? Not really but I am more cognisant of the transitions. Those stop/starts and the acceleration make a big difference since that makes up the bulk of my driving, short trips, I’ll continue to practice that over time and see how it averages out. I would encourage you to try your own experiments and see what works for you. You might not have the luxury of instantaneous MPG results so you’ll have to track from tank to tank. Good luck and let us know if you are a hypermiler and your tricks and tips.

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{ 4 comments… read them below or add one }

tperko 2009/07/20 at 5:24 pm

In Western PA it is hard to get “good gas mileage” but I do know that the best way to conserve gas is stay around 55mph an keep slow and steady acceleration and negative acceleration.

While drafting may improve your MPG it also will get you a nice fat ticket to offset any money you would have saved on fuel, not to mention insurance.
.-= tperko´s last blog ..PocketMod Food Diary =-.

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andyrow 2009/07/31 at 6:04 am

Hi, HAs anyone tried or knows of the hydrogen attachment to your regular vehicle to get better mileage. Does this really work? I am not that technical so if anyone knows about it or has it I,d really appreciate it.
http://www.bettergasmileagetips.org
.-= andyrow´s last blog .. =-.

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Jim Deville 2009/07/31 at 8:33 am

From what I’ve read, AC doesn’t make a difference on newer cars. It’s kinda sad to see that 55mph is such a big benifit. I calculated that you can drive for 4 more hours at 55 vs 70 assuming a 12 gallon tank.
.-= Jim Deville´s last blog ..Snoqualmie Falls PGA (Perfectly Great Amber) Ale =-.

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Jennifer @ Improve Gas Mileage Guide 2009/08/04 at 2:39 pm

I’m pleased to learn that you don’t recommend drafting to improve gas mileage, though it’s disturbing that you actually attempted it, especially behind a semi! YIKES!

I learned that it’s best to shut off your engine if you’ll remain idle for 30 seconds or more, not 7. If you shut off your engine any sooner than this, you’ll burn more fuel to restart the car than you would if you just kept the engine running.

Also, it’s said that, when you’re idle, to put your car in park or neutral, this will increase gas mileage. However, I’ve noticed my RPMs jump just slightly when I do this, so I need to test this theory for myself. I plan to post the results on my web site.

Thanks for testing these hypermiling tips. It’s helpful that you had on-the-spot gas mileage alerts for yourself to really test out the theories.
.-= Jennifer @ Improve Gas Mileage Guide´s last blog ..Hypermiling Your Way to Better Gas Mileage =-.

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