Advanced Techniques for Improving Gas Mileage

Note: My article on the recent trip to Choren is finished, but I am waiting to hear back from them before I post it. I signed a non-disclosure agreement before I toured the plant, and I want to make sure they are OK with what I wrote. As soon as I hear back from them, I will post it.

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I ran across an interesting article today. Some of the claims are suspect, but I may have to test some of them out:

“Hypermiling” drives savings as fuel costs soar

PHILADELPHIA (Reuters) – As U.S. gasoline prices hit records on almost a daily basis, an increasing number of motorists are following a radical driving technique designed to eke out every last mile from a tank of fuel.

Known as ‘hypermiling,’ the method can double gas mileage, even in gas-guzzling vehicles that would normally get less than 20 mpg.

Promoted on a growing number of Web sites, hypermiling includes pumping up tires to the maximum rating on their sidewalls, which may be higher than levels recommended in car manuals; using engine oil of a low viscosity, and the controversial practice of drafting behind other vehicles on the highway to reduce aerodynamic drag — a practice begun a few years ago by truck drivers.

That practice wasn’t begun a few years ago by truckers. I used to do it 20 years ago. But I don’t recommend the practice. It is very dangerous. I would also be careful about that tire pressure; I have seen a few blow out before.

As far as the claims go, I think some of these are pretty far-fetched. But I have never personally attempted any these techniques:

Adherence to hypermiling and other disciplines are designed to boost mileage well in excess of the U.S. Environmental Protection Administration’s official ratings, which apply to each car model.

Wayne Gerdes, a former nuclear plant operator from Wadsworth, Illinois, and the originator of hypermiling, said he gets 40-70 mpg out of his Ford Ranger pickup truck, about doubling its official fuel consumption of 25 mpg.

Hypermiling can even make fuel-sipping gas-electric hybrid cars more efficient. Chuck Thomas, 50, a computer programmer from Lewisville, Texas, said he has been getting 71 mpg from his Honda Insight, a hybrid whose EPA rating is 58 mpg, in the two years since he has been hypermiling.

Those kinds of claims sound to me like “you can run your car on water.” Anyone have any first-hand knowledge of getting much more than the EPA’s official ratings?

18 thoughts on “Advanced Techniques for Improving Gas Mileage”

  1. Some of these guys do all sorts of silly things, like taking corners at high speed to avoid braking and the subsequent re-acceleration, turning the engine off and coasting to a stop when a red light is seen up ahead, putting under-spec headlights/electrics in to avoid battery drain… Go and read one of their forums and you’ll see all of this stuff and more.

  2. Up until the day it was totalled, I got 38-42mpg in my ’96 Accent, which, under the current ratings scheme would have been rated 33mpg highway by the epa. This is without over-inflating the tires or do anything out of the ordinary… just accelerating reasonably, doing the speed limit, and coasting to stops. 45-46mpg was possible when drafting semis with over-inflated tires. A nice improvement, but nowhere near doubling the epa mileage. Hypermilers use “ridge riding” and “pulse and glide” techniques which I didn’t feel were safely practical in my commute.

  3. Years ago, a mechanical engineer told me that I could get great mileage and/or great performance if I just put 5-weight oil in my car…and then I would have to overhaul the engine soon thereafter. Quite a bit of engine drag is due to oil viscosity, but it’s for a good cause.

    This page has interesting info on multi-weight oils and such:
    http://www.waynesgarage.com/docs/oil.htm

  4. I have had for years an idea of how to improve mpg’s in towns and cities throughout the USA. It would cost us consumers nothing more than the tax dollars we already pay.

    Simple really. Now I don’t know how bad it is where you all live but here in Las Vegas I would venture to say we have the worst coordinated/timed traffic lights I’ve ever seen.

    Forget rush-hour as the immense amount of vehicles on the road make it impossible for conscious effort to make the next light. But for being a 24-hour town I routinely get aggrevated when I am driving past midnight and have to heavily break for a red light then sit there in amazement of not a car in sight. Only to speed up and catch a green the next one but another red down the road despite going the speed limit and knowing lights are supposed to be timed to the limit.

    BS. Either that is a myth or I picture some high level traffic guy sitting around his office browsing the net waiting for lunch who has never ventured out past 10pm in {city of chouice}.

    How about when a couple cars are cruising a major road and have caught the past few lights only to have a random car on a side street make us all stop only so he can get an arrow. 5+ cars all just dropped their mpgs by 50% so 1 car can avoid idle while we all pass.

    Better timed and coordinated traffic lights in every city could easily increase mpgs for everyone. And probably dramatically considering stop-go is usually almost half of what cruising speed mpg is.

    I get po’ed just thinking about it as I do a lot of night driving and have this happens a lot to me despite best efforts.

  5. I know not the right place to post, but this got my blood boiling. Hillary Clinton was on Fox news last night. The part 1 of interview is here: Senator Clinto on Bill O’Reilly . Go to the 3:20 mark. Mrs. Clinton says this:

    HRC: “The oil companies have made out like bandits, you know that. We all know that, right?

    BO: “Yes”

    HRC: “There is no basis for them to have these huge profits. They’re not inventing anything new.”

    BO: “What are you going to do, take 20% of their profits away from them?”

    HRC: “You set a baseline, and above that baseline you begin to tax their profits.”

    This is mindnumbingly stupid. First, “make out like bandits”? Profit margins for oil companies are in line with other US industries. The large profits come from the large size of these businesses.

    Mrs. Clinton implies that oil companies don’t pay any taxes, and that above a “baseline” she would begin to collect taxes. Either she is stupid or deliberately misleading. What she is saying is she wants MORE taxes above some threshold.

    Well what can you expect from a politician? I’ll bet even our CEO can operate a coffee machine. Hillary Clinton tries to be a regular person.

  6. Not inventing anything new???

    Guess those billions in R&D are just a waste. Cancel Offshore Technology Conference in Houston this year. Nothing new to see, move along.

    Breathtakingly stupid, pandering, just another out-of-touch politician.

  7. These Prius hypermilers managed 109 mpg on public roads one weekend. 1397 miles on a single tank! They used pulse-glide but no drafting.

    The math is straightforward. Prius needs 3-4 kW to sustain 35 mph. In normal operation even the Prius Atkinson cycle is not very efficient at such low power. But at the 12 kW or so needed for gentle acceleration it’s 35% efficient. So they accelerate to almost 40 mph (pulse) and then back off the accelerator such that the car coasts with the engine off (glide). All gasoline is then burned at high efficiency, extracting about 12 kWh out of each gallon which is enough to travel 3-4 hours or 100+ miles.

    My minivan does 25 mpg on the highway. It’s not hard to keep the instantaneous mpg above 30 drafting semis at a slightly unsafe distance, but to maintain 40+ you’d have to be very close. Mythbusters showed a 40% drop in fuel consumption at 10 feet (!!), which would take a 25 mpg vehicle to 42 mpg. Note that was at 55 mph, the relative improvement would be better at 70.

  8. doggy – You can save a lot of gasoline by drafting – especially after you are dead from the horrible accident.

    Last summer I experimented with hypermiling our minivan. In normal driving I got 18-19 mpg. I switched to synthetic oil, ran the tire pressure up to 42 psi, stripped out excess weight, even the spare tire and floor mats. Then I worked hard to manage driving, including some pulse-gliding. I tried to eliminate as many stops as I could by managing speed and route. No drive-thrus. Best I did was 26 mpg, about a 40% improvement.

  9. I have consistently gotten 60+ mpg from my 99 VW TDI golf by careful driving, and careful maintenance…
    tire selection, clean air filter, syn. oil, etc.. No pulse and glide though. That would get you killed in CA.

  11. So King, I am guessing that there isn’t a “Clinton for President” sign in your front yard? 🙂

    I find those kinds of comments incredibly frustrating. I think the issue is that politicians use these kinds of tactics – find an enemy and heap all troubles on that enemy – to deflect away from policies that have put us into this position. It’s not the government’s fault (of course it is the “other party’s” fault). It’s not the consumer’s fault. No, oil companies are responsible for the situation you are in.

    RR

  12. “Advanced Techniques for Improving Gas Mileage”

    One of the most advanced techniques would be to use a bicycle for trips of five miles or less.

    If everyone* in the country used a bike for most of their trips of less than five miles, our oil consumption would drop significantly.

    * With the obvious exceptions for handicapped, etc.

  13. So King, I am guessing that there isn’t a “Clinton for President” sign in your front yard? 🙂

    Good guess. And to think I almost voted for her in the Texas primary.

    You won’t find a McCain sign or Obama sign either.

    The Arab states blame their problems on Israel, US politicians have “big oil”.

    My question is if there were NO U.S. oil companies would prices be the same or more?

  14. Rum doodle – If everyone* in the country used a bike for most of their trips of less than five miles, our oil consumption would drop significantly.

    I already do, if the weather is good and I don’t have to carry too much. I even walked to my Dr’s office! First time I’ve ever been able to do that.

  15. I get 32mpg in my 2001 Toyota MR2 Spyder (EPA 22-27). My improved economy is probably due to:

    1) Reduced back pressure due to an aftermarket muffler.

    2) Timing lights so I don’t have to come to a full stop.

    3) Reduced weight a) the aftermarket muffler is 13lb lighter b) I use a battery designed for a motorcycle and is 4 lb lighter c) I cary a can of fix a flat instead of the spare tire, 20lb lighter.

    4) on long trips I shift to nuetral on downhills and coast.

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