How do you reduce your fuel consumption by pointlessly driving in hypermiling challenges?

Seems like 13.7 gallons of gas that he really didn't need to use, not to mention the gas he used to get to the competition (whether by car or plane).

Filed under 'non-green activities'

Nick, sorry to say, but that's near-sighted thinking.

We could probably save a few kilowatts too by shutting down all green websites, but their value is in spreading information, getting people interested, and showing what can be done.

Same with hypermiling concepts. A bunch of people will read about it in their paper and on treehugger, and even if a few hundreds of them change the way they drive just a bit, they'll save a lot more than all the gas used in that competition.

Just yesterday I told a friend that keeping the A/C on used more gas in her car. She didn't know, so always drove with it on even when it was cold outside.

Teaching people is worth a lot.

Good point Nick! Take into calculation the infectious spread of hypermiling through his achievements and he's saved even more (even with trip to contest and 13.9 gallons included)

If you are coming to a stop, why would it matter if you use your brakes?

"If you are coming to a stop, why would it matter if you use your brakes?"

You can use your brakes, the point is to take your foot off the gas pedal as long in advance from the stop as possible, instead of keeping it on the gas until the last moment and then immediately braking hard.

I'm all for hypermiling, BUT DO NOT inflate your tires to the maximum rating on the sidewall.

A tire in a landfill is a heck of a lot worse than the extra gallon of gas you'll use this year by inflating to manufacturer's specs. There's a reason manufacturers put the numbers on the car, and it ain't so they can sell more tires.

Hypermiling isn't one technique, but a toolbox full of techniques which each person can use to suit their own style.

Likewise, seeing one "red flag" technique in an article shouldn't cause you to write off the whole field. There are over a hundred techniques listed in the forums at ecomodder.com ... and that's before you start making changes to your car to improve your drag coefficient.

i think a car running on hydrogen that is charged by tiny soalar panels on the roof of the car or paint that produces power to conver t the water into hydrogen.and seeing that it produces hydrogen instantly there is no need for tanks to hold the gas .and no more explosions in an accident its only water and will probaly put the fire out.
come on how easy is this but if the oil company finds you they will put u out of action

I learned about hypermiling from TreeHugger, so yes, the exposure is worth the "frivolous driving".
And a clarification on braking: When you're stopped, you're getting 0 miles/gallon. If you can coast into a red light, you aren't accelerating unneccesarily, and may even be able to avoid the redlight altogether (allowing you to maintain a steady speed and avoid the extra power needed to accelerate from a dead stop).
I've been averaging 35 mpg in my Saturn SL1 for about 3 months now with 40-50mpg spikes during my long distance trip to Chicago (which was required...for the record).

Turning off the A/C when it is cold is a good thing to do, but when it is hot the A/C is actually more fuel efficient than the drag created by open windows unless you are going under about 30 mph. Drag from open windows increases with speed, but gas used by A/C is a constant.

No doubt drafting improves the gas mileage of the Insight, unless you count the fuel used by the car plowing the air cavity you are ducting through. It would also improve your mileage to be pulled by a tow truck. I'm just pointing out that that is an efficiency not attributable specifically to the record breaker, but to the combined operation of two vehicles in convoy. So it's probably not an appropriate technique for competition.

Andy, but the vehicle in front doesn't push more air because you're drafting, so you are using energy that would otherwise be lost, no?

Glad to see this come up so often. My own trick on coasting into red lights is to take the car out of gear, turn the thing off (Key goes back into the on position). 1/2 of the time the light turns green when I get near it, and I put the car back in gear, let out the clutch and off I go. I am over 50MPG at this point. My comute is a little long, so I use about a gallon a day, rather then the gallon and a half I was using. I also over inflate my tires a bit, about 10%, and I widen my spark plug gap about 10% for a slightly hotter spark.
(No, I aint movin off the farm to be closer to work, and live in a rabit hutch)

Well - I think hypermiling is a great concept which everyone should learn. But I really object to unsafe hypermiling methods. People's lives are valuable, they have loved-ones and family members. And when a hypermiler drives dangerously, he is not just endangering his own life, but lives of others and that includes people he has never met.

Otherwise I love anything which reduces harmful effects on the environment, or the promotion thereof. And I really like the post pointing out that we would save a few kilowatts by shutting down all the green websites but ...

I would just really like to see people using safe hypermiling techniques, to get better gas mileage and save money and reduce environmental impact, without putting anyone in danger.

Don't always know about the a/c windows thing. Driving along a common strech of road where I typically get 80mpg with the windows partially down, my friend wanted to a/c on. That took the gas mileage down to a little over 50mpg. The speed traveling was 45mph.

So I'm wondering if the drag effect varies on the different model of vehicle. Some may have more efficient air flow over the car

Super-inflating tyres is all very well, but wear and tear issues aside, friction is related to traction, so as your now harder tyres will have less contact with the road, your braking and cornering will be affected.

By how much, I couldn't say, but as long as you're driving at hypermiling speeds and accelerations, you should be fine... :-)

13.7-gallon tank of gas?

The Insight has a 40 liter (10.6 gal.) tank.

Hypermilling is dangerous... years ago, long before it became such a fad, I got the idea that it might work after hearing something about a manufacturer claiming that it was actually more efficient with fuel injected cars to accelerate quickly to the desired gear and then let off.... I played around with it for a while, until one day the guy in front of me suddenly slammed on his brakes, got out of his truck, and came back and started to beat on my window which I was furiously rolling up. He thought that I was driving aggressively and had come to fight!!! Yikes! I guess I can see now how accelerating until you're close to his bumper, backing way off (coasting), and then accelerating up to him again could be seen as aggressive. :-) I did get great mileage though! Now I'm a "mild hypermiller"... I do it when it makes sense and can get the (pre 2008) EPA rating for freeway driving while driving in town.

Inflating your tires to the max pressure on the sidewall will not make your car unsafe. Actually the exact opposite is true. You will get better traction because more of your tire is in contact with the road and you will get longer life out of your tires. I did a lot of radial drag racing through the years and always got better traction with overinflated tires. On my street car I never get less than 70,000 miles on touring tires and 50 to 60,000 on Michelin 50 series sport radials with an A traction rating.
The main reason tire manufacturers tell you to in flate your tires to 34 psi and not the 41 psi oin the sidewall is because they do not want people to complain about a rough ride with their tires.

"Andy, but the vehicle in front doesn't push more air because you're drafting, so you are using energy that would otherwise be lost, no?" - Anonymous

There are 2 forces at play in your aerodynamic coefficient (the number that says how much force is needed to move through air - I think the Prius is around 0.21). One is the obvious force of the air that gets pushed out of the way as you literally make a hole as you move forward. This is the "drag" that most people think about - the high pressure you feel on the front of your hand when you stick it out the window on the highway. If that were the only force the coefficient would be huge and even a Prius would only get 2 gallons per mile (not a typo). But the other less-obvious force is the partial vacuum left just behind your car, which greatly counteracts the high pressure on the front of the car. Not completely, but a lot. If you want proof of the different pressures, stand on the deck of a fast-moving boat. Its easier-than-normal to breathe when you face forward because of the high pressure, and noticeably harder to breathe when you face the rear.

It all comes down to the law of conservation of energy.

When you draft someone you shift most of the 1st car's vacuum to behind your (2nd) car, while also keeping the nose of your car in what's left of the 1st car's vacuum. You get a higher MPG because now you have less pressure on your front, and even more vacuum on your rear. However, the 1st car still has the full pressure on its nose but very little of the vacuum to counteract it on its rear. The 1st car's MPG goes up. Conservation of energy - the energy to move your car has to come from somewhere, so now it comes from the poor guy in front whom you are tailgating.

So you save gas by using more of his gas. No net savings.

And I should note that someone tried this on me just last week, and I wasn't happy about it. Please don't draft/tailgate!

Wide-open highway, few cars, I even had the cruse-control on which can rarely be used in my area due to congestion. I gradually passed this guy who was in the right lane. Just as I pass he jumps right behind me, speeds up and stays there. So close I can't even see the tops of his headlights. At first I thought he just timed the lane-change wrong and would back off. After a half-mile I then thought he was being an ass, but since I hadn't done anything to him I didn't know why. Then it hit me, he's drafting me! By this point I was really feeling unsafe - and angry that he was endangering me and my car and using my gas - so I turned the cruise control off to loose speed. No brakes, I didn't want him to hit me. Still no cars around so he could have passed me if he wanted. Instead he starts flashing his lights and honking his horn like I'm going to speed up and let him keep drafting me. I continued to slow down and he finally backed off.

Moral of the story - don't draft people, you are only going to piss them off and many people won't let you! And after reading my last post above, you'll see that you aren't saving ANY gas by doing it. None.

CNCMike - If your car isn't heavy enough, inflating your tires to max will cause them to dome. Then you are riding on a much smaller part of your tire, which wears the tire out faster and gives you much less traction in cornering, accelerating, and braking. The recommended tire pressure isn't just for ride comfort, its for safety, too.

Trust me on the tire pressure. I worked for Michelin for 2 years when I got out of the Navy. Next time your driving make a point to look at all the tire marks on the road, Most of them will be two dark lines from the edge of the tire and very little color in the middle. This is because at the recommended pressure you do not get full contact of the tread width under hard braking or acceleration.

Is there any chance the Honda Insight wil be brought back or replaced?

Is there any chance the Honda Insight wil be brought back or replaced?

Doug, you are wrong. The implication of your hypothesis (conservation of energy), is that all bodies have equal form drag -- which of course isn't true. Consider a scheme in which the front vehicle has a truncated trailing section (e.g. a semi trailer) and therefore creates lots of separation, and form drag. Now suppose that the second vehicle has a front surface which mates perfectly with the back surface of lead vehicle, but also has a lovely sharp trailing edge (so the Kutta Condition applies). And let's also assume that the two vehicle are separated by a nanometer. In that scenario both vehicles benefit -- and that is the approximate scenario of a Honda Insight following a tractor trailer rig.

Now that's not to say that I'm an advocate of drafting...I'm not (necessarily). My experience, after having logger over 100k Insight miles, is that drafting works best in the steady state, i.e. no transient acceleration. Here in the Northwest there are too many hills for (really) effective drafting.

Tailgating isn't "controversial"; it's dangerous and illegal.

The way tires are designed to work maximizes their grip when slightly underinflated. If you decide to take advantage of the reduced rolling resistance afforded to higher tire pressures, be aware that you are then driving with less cornering and stopping power. Especially under wet road conditions. If you do this, you might want to go somewhere with no other traffic (or anyone else who may become upset or alarmed) and do a few hard stops from different speeds under safe circumstances, so as to become aware of how your vehicle responds with less traction. If you wait until you are forced into a hard stop by traffic, you'll have to guess at how much extra room to allow at which speed, and it's very easy to be mistaken in such estimations.