How to Become a Hypermiler

83,937

49

217

Engineer making renewable energy products for African entrepreneurs.

Intro: How to Become a Hypermiler

The best way to save on fuel is to not use it at all - ride a bike, use mass transportation, etc. However, there is a rather large subset of the population that live in a suburban prison. The following is a set of techniques used by people that call themselves hypermilers to achieve high fuel economy/efficiency (FE) numbers, save the planet and save their wallets.

Step 1: Tires

Inflate your tires to, at least, the maximum inflation pressure to reduce rolling resistance.

Should you wish to go beyond, that is up to you. Personally, I inflate my tires to around 55psi (they are rated for 44). Please do not attempt on old or visibly damaged tires. My tires are new and in excellent condition.

Modern tires are radially belted - that is, they won't balloon like tires of yore. Keep in mind what you're doing though. You are reducing the contact patch of your tires in order to decrease static friction. This will reduce your overall braking ability. So riding someone's bumper at 80mph is just that much more dangerous. Again, these steps only work when combined - you can't pick and choose.


When it comes time to buy new tires, look for low rolling resistance (RR) tires. While they may not have the same 60,000 mile (or even 40,000) guarantee, they will save you in the fuel department. The Toyota Prius comes equipped with LRR tires.

Step 2: Weight

Take everything out of your car.... Then put back only what you need.

For those more daring, remove your emergency jack and spare tire and be sure to carry a cell phone in case of emergency. AAA is a good thing to invest in - even if you don't plan on following these mileage techniques.

If you won't be carrying passengers, remove your rear seat and passenger seat as this will lighten your load by a couple hundred pounds.

Step 3: Maintenence

Keep your engine in Tune and use the lightest weight of oil as possible. In addition to friction, you also have to combat viscous forces. The thicker the oil, the more resistance your engine has to overcome.

O2 sensors are very critical pieces of equipment - especially the 1st one (primary).

If you have a check engine light (CEL) and your car is a 1996+ model (for US vehicles) - get your car scanned. Certain auto parts places will scan codes for free (such as Autozone). Fixing parts yourself can save a lot of money - that is, only if you feel comfortable doing it.

Step 4: Reduce Driving Loads

That is, load placed on your engine. Avoid using the following

  • Air Conditioning
  • Defrosters
  • Loud Sound Systems
  • Headlights (that means, try driving in the day rather than at night)


You can't get something from nothing. The greater the load you put on your alternator - the harder your engine has to work to turn it. As a corollary, the more amperage you put into a motor, the greater the torque it will provide...

Step 5: Instrumentation

Install a trip computer that can give you instantaneous fuel consumption feedback. Then, turn driving into a game - always try to beat your highest score.

Nissan, according to internal testing, estimates gains in fuel economy ~10%
All New Nissan Vehicles will be equipped with fuel consumption instrumentation.

Toyota Estimates 5-10%, and They too will include instrumentation in new vehicles

Step 6: Pulse and Glide

Assume you want to average 35mph.

Start at 40mph and allow your vehicle to decelerate, in Neutral, to 30mph -- this is called the glide.

Then, accelerate back up to 40mph in the same amount of time that your glide took -- this is called the pulse.

For the more intense, glide with your engine off. This will increase your FE number dramatically while gliding in gear will reduce them as you'll be combating engine braking.

This technique has been proven many times over to be an effective way to increase mileage. But, your mileage will vary based on traffic and other drivers. Other drivers will get quite pissed off at your pulse and glide, so use your best judgment.

Step 7: Hills

Avoid accelerating up hill. Try to coast up hill or, at the very least, maintain constant throttle (not speed). Then, while going back down the hill, accelerate back to your cruising speed.

Step 8: Traffic Lights, Stop Signs, Traffic

The instant you see a red light from a brake light or the yellow/red light from a traffic signal - take your foot off the gas and coast. It's no use speeding up into a stop.

The same goes for approaching a stop sign.

Step 9: Acceleration

The best way to accelerate is by keeping your engine at peak torque. This means, accelerating too slow (as you may have been told to do) and accelerating too fast (bringing your rpms up high) are inefficient and will reduce your fuel economy numbers.

Ideally, peak torque at 50-75% throttle.

Step 10: Aerodynamics and Modification

Aerodynamics are important to a car. It's hard to make a car better aerodynamically - but it's very easy to make it worse.

*Blocking your grille has proven to be effective - just remember that your radiator (and grille opening) were designed for the worst case cooling scenario. So monitor your engine temps and adjust your grille opening accordingly.
  • Fold your mirrors. If you can, fold your rear view mirrors in. Just be sure to stay in compliance with local laws.
  • Belly Pan - A significant amount of resistance comes from the open areas under your car. Covering them with corroplast or some other material can reduce your drag coefficient (Cd)
  • Wheel skirts - covering your wheel wells to keep your cars body one contiguous object can help
  • Air Dam - see image, if you car doesn't have one already, this can help
  • Always Drive with your windows up

The best thing you can do to help your aero resistance is to slow down. Resistance goes up with the cube of your velocity (holding everything else equal).

Step 11: Pretend You Have No Brakes

If you didn't have brakes, you'd only go as fast as you needed to ensure you could stop at your next destination. That is, don't apply so much power that you'll only be throwing away your engery VIA braking.

Coasting is your friend.

Step 12: Join a Community

Find an online community to talk with and collaborate. There are plenty of people more experienced and knowledgeable than I.

Personally, I'm fond of the people on Gassavers. You'll find plenty of experiments that, quite commendably, follow a scientific method structure.

Step 13: Credits

Images came from flickr searched for using the creative commons licesnce. Some images came from metrompg.com

Share

    Recommendations

    • Furniture Contest 2018

      Furniture Contest 2018
    • Metalworking Contest

      Metalworking Contest
    • Fix It! Contest

      Fix It! Contest

    217 Discussions

    0
    None
    ac-dc

    7 years ago on Introduction

    There are so many things wrong with this instructable I don't know where to start.

    Do not over inflate tires. It is dangerous, should be illegal and might be, will wear them irregularly in the middle regardless of being radial belted. The proper inflation level depends on the vehicle weight and is usually stamped on the the vehicle door sticker or elsewhere.

    Seats don't usually weigh 100+ lbs each, even if they are motorized, not even a full bench rear seat.

    There is nothing to "tune" on a modern fuel injected, computer controlled engine. It's sort of a myth perpetrated by youngsters repeating what old timers said back when engines could be tuned manually without reprogramming a memory chip.

    It is very ill advised and dangerous to suggest not using air conditioning (heat delirium while driving causes accidents), or defrosters (which you'd only use to get rid of frost, it's illegal to not keep visibility by choosing not to use a defroster when needed). Further, if you can't see traffic or traffic control lights, signs, etc, due to frost or fog you can't plan your acceleration and deceleration as well.

    One thing not mentioned was that on some vehicles you can change the vacuum tube configuration to make the AC system blower blow out the defroster ducts without it in defrost mode so you can clear windshields without running the AC compressor and incurring the additional engine drag, but be sure to keep the vac system a sealed system as an open (leak) will cause CEL to come on and you'd be in the inefficient computer open loop mode in many cases.

    Pulse and Glide driving is not proven to increase mileage in general, only with hybrids and certain ICE vehicles. With most (other) vehicles the more effective driving is to accelerate at the engine's peak efficiency RPM then maintain approx 40 to 45 MPH, or the speed limit if it is lower than 40 MPH. This in fact _has_ been proven constantly to have better fuel economy. Pulsing up to speed again is "usually" less efficient than maintaining the average speed. Of course certain engine and transmission combinations can change this, but it was suggested as if it's always an improvement to pulse and glide when it isn't.

    Constant throttle up a hill does noting to improve fuel efficiency. Keeping the throttle varied so the engine always stays within its peak efficiency RPM is more fuel efficient.

    Engine off coasting may be illegal, but it can be done safely if the driver is either very strong/small car so steering effort is manageable, or it has electric steering so the battery is enough of a reserve to power it. Brakes are the same thing, there is reserve pressure for one stop or pumping can build it up, but of course either is still less safe.

    The suggestion about 50-75% throttle is only valid for small cars with anemic engines and matching gear ratios/shift points, with no traffic around. Otherwise you could be accelerating too fast, unsafely and putting stress on the vehicle and tires. Often if you accelerate a little slower, you have more time to react to road conditions or vehicles ahead of you. Point is, the exact situation changes which acceleration strategy is most efficient.

    Blocking your grill has not proven to be effective, except on select vehicles! You're making blanket statements that are incorrect a large % of the time. It is not just a matter of reducing drag or cooling system temperature, it is a matter of how the computer changes engine fuel air mix due to the temperature of the engine. Sometimes it helps, other times not. It will have to be tested per each vehicle and also with different driving speeds and ambient temperatures. Also, most cooling systems rely on electric motor(s), it causes more alternator load to block the radiator.

    To summarize, sometimes these strategies help but other times they not only don't help but increase vehicle wear, risk of an accident, road rage from other drivers, and are illegal. It is no more reasonable to break laws to save gas than to break laws because you feel like robbing a bank to buy more gas. Vote to change things, and petition your government representatives for change.

    4 replies
    0
    None
    LazyHac-dc

    Reply 2 years ago

    Also, you can adjust simple things like fuel and ignition timing to create a more efficient burn. Consumer vehicles are full of compromises to fit as many potential customers as possible. For example, if company A leaned out their fuel mixture, certain drivers might experience preignition during certain rough driving techniques, therefore they don't lean out their fuel mix. Hypermilers who won't use those harsher driving techniques don't have to worry about those risks and can therefore tune the vehicle for a leaner burn and therefore greater fuel efficiency than stock, at the expense of power and versatility. The same thing can be said for ignition timing, if the ignition is advanced too much it can cause damage in certain circumstances, however fuel efficient driving (again) typically avoids these scenarios, and the ignition can be advanced without concern for damage to the vehicle, again at the expense of versatility of the vehicle (not at the expense of power though, since increased ignition advance increases both efficiency AND power). Of course, the benefits of both are minute in most vehicles and are typically best applied to tune a vehicle to better utilize certain engine mods.

    0
    None
    LazyHac-dc

    Reply 2 years ago

    In terms of pulse and glide technique, it actually works well for all vehicles, it simply might require impractically large differences between max and minimum speed for certain vehicles. Hybrids actually are worse with pulse and glide because what energy you would have saved by conserving your momentum in the glide will usually get a loss by being converted to electric power and back with waste heat as a byproduct. Pulse and glide partially works by reducing engine restrictions, with more open throttle there is less restriction on the engine trying to pull in air, this is why all of those milage competition vehicles with less than a fraction of a liter engines getting 3000+ mpg always run full throttle. Pulse and glide works also by placing the largest possible load on an engine, which causes more fuel to be converted into energy. This is why pulse and glide is more difficult in an automatic without manual override, because it is harder to keep the engine in the ideal range with 50-75% throttle without causing the tranny to think it has to keep the engine at high RPMs which would ruin any gains. With a manual selector/tranny, you can keep the engine in the ideal rpm range while still maintaining the 50-75% throttle that both reduces intake restrictions and increases engine load. Keep in mind, for a given rpm range load from throttle increase does not increase at the same rate as fuel consumption in a given RPM range.

    A more scientific explanation is that the higher your EFFECTIVE compression ratio the greater amount of power for a given amount of fuel and therefore more power and fuel efficiency for a given throttle position. For example, lets say 50% throttle position lets in twice as much air which is therefore compressed twice as much as the amount of air at 20% throttle. You might be accelerating at both throttle amounts, but for a given RPM range 50% is more efficient because the engine "sees" a higher compression ratio, you're basically doubling your EFFECTIVE compression ratio by increasing throttle which would increase fuel efficiency by itself even without less intake restriction.

    In another sense, you can increase fuel efficiency to an extent by increasing the GEOMETRIC compression ratio in your engine through head milling or thinner gaskets. The only reason we don't see extremely high compression ratios (14-1 and up) is because of preignition at such high compression ratios which would require very special and expensive fuels to counteract, and because the engine would wear out a lot sooner due to much higher loads. If those obstacles were overcome, one would find that as compression ratio increases, exhaust temps would decrease closer and closer to absolute zero, since more energy is being converted to motion rather than heat (would still have to deal with waste heat in the radiator though).

    This is also why turbochargers can increase fuel efficiency if sized to an engine right and driven for efficiency rather than power, they not only increase intake efficiency through wasted exhaust energy, but also increases the effective compression ratio. True, there is a slight amount of restriction to the exhaust but when driven right those restrictions are nowhere near as great as the gains from increased intake efficiency and compression ratio. The turbo basically has the same effect as an atkinson cycle engine, higher compression for a given amount of intake restriction.

    0
    None
    jimmytvfac-dc

    Reply 6 years ago on Introduction

    just look at the tyre that's on the picture, is like a ballon, overinflated and blown up

    0
    None
    mijhy

    7 years ago on Step 6

    As a professional driver, i thought i would add my 2cents to this particular step. While they are obvious benefits of "coasting" I want to point out it can also be very dangerous. In a winter climate much of the control you have over your vehicle is from your engine, disconnecting it from your wheels leaves you no chance to correct a slide if you get into one. Yes you could only do it in summer, but once you fall into a familiar practice it would be all to easy to repeat it with out thinking, and then when your in a ditch or upside down you realize that 1% gain in fuel efficacy wasn't worth it. There are some comments about brakes going down hills, well of coarse you have to break, but what if you coast to a stop light, forget your not in gear, and roll back into another car. Every state is different on passenger cars, but it is federal law, that any commercial vehicle never be out of gear for more than a few seconds (time to shift). Again its only my 2 cents, but it is something to keep in mind.

    2 replies
    0
    None
    LazyHmijhy

    Reply 2 years ago

    In terms of pulse and glide, depending on your vehicle and technique you can get over 50% increase in fuel efficiency. That and often in ice it's easier to regain traction with no load on the tires, which would help them regain traction sooner, at least for the majority of drivers out there.

    0
    None
    ac-dcmijhy

    Reply 7 years ago on Introduction

    while using powered traction to get yourself out of a slide works for professional drivers, the average person on the road tends to overcompensate trying to do so and ends up that much worse out of control than if they only concentrated on steering and braking.

    0
    None
    swander

    7 years ago on Step 6

    This is a joke. If you dont have a hybrid or electric car, this pulse and glide is a wash. Take a carbureted car for instance: Every time you mash the pedal, you are squirting up to 80cc of raw fuel into the carb (Holley 850 DP with 50cc pump on rear) This is an extreme example but it is a valid concern. This fuel is way more than is needed to combust so you get the telltale black puff out the rear. Keeping a steady rate will net more mileage than this dangerous illegal practice of turning the motor off or varying your speed 25% on a shared road.

    1 reply
    0
    None
    LazyHswander

    Reply 2 years ago

    It actually works well for all vehicles, it simply might require impractically large differences between max and minimum speed for certain vehicles. Hybrids actually are worse with pulse and glide because what energy you would have saved by conserving your momentum in the glide will usually get a loss by being converted to electric power and back with waste heat as a byproduct. Pulse and glide partially works by reducing engine restrictions, with more open throttle there is less restriction on the engine trying to pull in air, this is why all of those milage competition vehicles with less than a fraction of a liter engines getting 3000+ mpg always run full throttle. Pulse and glide works also by placing the largest possible load on an engine, which causes more fuel to be converted into energy. This is why pulse and glide is more difficult in an automatic without manual override, because it is harder to keep the engine in the ideal range with 50-75% throttle without causing the tranny to think it has to keep the engine at high RPMs which would ruin any gains. With a manual selector/tranny, you can keep the engine in the ideal rpm range while still maintaining the 50-75% throttle that both reduces intake restrictions and increases engine load. Keep in mind, for a given rpm range load from throttle increase does not increase at the same rate as fuel consumption in a given RPM range.


    A more scientific explanation is that the higher your EFFECTIVE compression ratio the greater amount of power for a given amount of fuel and therefore more power and fuel efficiency for a given throttle position. For example, lets say 50% throttle position lets in twice as much air which is therefore compressed twice as much as the amount of air at 20% throttle. You might be accelerating at both throttle amounts, but for a given RPM range 50% is more efficient because the engine "sees" a higher compression ratio, you're basically doubling your EFFECTIVE compression ratio by increasing throttle which would increase fuel efficiency by itself even without less intake restriction.

    In another sense, you can increase fuel efficiency to an extent by increasing the GEOMETRIC compression ratio in your engine through head milling or thinner gaskets. The only reason we don't see extremely high compression ratios (14-1 and up) is because of preignition at such high compression ratios which would require very special and expensive fuels to counteract, and because the engine would wear out a lot sooner due to much higher loads. If those obstacles were overcome, one would find that as compression ratio increases, exhaust temps would decrease closer and closer to absolute zero, since more energy is being converted to motion rather than heat (would still have to deal with waste heat in the radiator though).

    This is also why turbochargers can increase fuel efficiency if sized to an engine right and driven for efficiency rather than power, they not only increase intake efficiency through wasted exhaust energy, but also increases the effective compression ratio. True, there is a slight amount of restriction to the exhaust but when driven right those restrictions are nowhere near as great as the gains from increased intake efficiency and compression ratio. The turbo basically has the same effect as an atkinson cycle engine, higher compression for a given amount of intake restriction.

    0
    None
    reddeth

    11 years ago on Step 6

    It takes a lot of power to get up to 40 MPH, even going from 30, this glide on/off idea is not only dangerous, but cannot stand to be truly effective, you're using a lot of an engines power to make it back to 40 MPH, this may be different for electric/hybrid cars running on the electric motors, which in turn use deceleration and braking to generate more power but on a traditional gas powered car this would not be a productive enough maneuver to outweigh the danger you present to other motorists by the constant accelerating/decelerating.

    6 replies
    0
    None
    trebuchet03reddeth

    Reply 11 years ago on Introduction

    ...but cannot stand to be truly effective...

    The pulse and glide method has been empirically tested by many people. Remember, while linear energy (momentum) is conserved - power is not. This is where the pulse and glide method shines. As for danger, possibly. I find myself much more alert and in every defensive driving course I have taken - evasive action is done by braking and steering.... Not gas and steer ;) Also take into consideration that you should be giving yourself plenty of space to begin with ;)

    Here's Just one, well written example

    0
    None
    reddethtrebuchet03

    Reply 11 years ago on Introduction

    I still find it questionable, but this isn't a forum for discussion, thank you for the link, thats all I'll say on the subject.

    0
    None
    trebuchet03reddeth

    Reply 11 years ago on Introduction

    I still find it questionable,

    That exactly the attitude I want from people :) And I mean that with no sarcasm whatsoever :D Go out and test for yourself, see what data you end up with :D There are some better explanations out there which I can dig up if you'd like - but all I ask is that you keep an open mind :)

    But, as a quite example from my numbers.... I might pulse for 7 seconds while getting 20 or so mpg -- and then I'll glide for at least double that getting ~180-200 mpg (that's engine on, clutch off). If I were cruising for that same 21 second period, I might be getting 31. That's not enough information to put everything together (I'll have to go out to my car and grab my notebook for that), but perhaps that glide number brings it into the realm of feasibility for you ;)

    0
    None
    ac-dctrebuchet03

    Reply 7 years ago on Introduction

    The correct answer is that for most vehicles pulse and glide results in worse fuel economy. It only helps with specific vehicles, most of which are hybrids.

    The problem is the method was suggested as if it applies to any vehicle (by omission of vehicle parameters necessary to benefit from it) when for "most" people it is worse because most people don't own applicable vehicles.

    0
    None
    LazyHac-dc

    Reply 2 years ago

    It actually works well for all vehicles, it simply might require impractically large differences between max and minimum speed for certain vehicles. Hybrids actually are worse with pulse and glide because what energy you would have saved by conserving your momentum in the glide will usually get a loss by being converted to electric power and back with waste heat as a byproduct. Pulse and glide partially works by reducing engine restrictions, with more open throttle there is less restriction on the engine trying to pull in air, this is why all of those milage competition vehicles with less than a fraction of a liter engines getting 3000+ mpg always run full throttle. Pulse and glide works also by placing the largest possible load on an engine, which causes more fuel to be converted into energy. This is why pulse and glide is more difficult in an automatic without manual override, because it is harder to keep the engine in the ideal range with 50-75% throttle without causing the tranny to think it has to keep the engine at high RPMs which would ruin any gains. With a manual selector/tranny, you can keep the engine in the ideal rpm range while still maintaining the 50-75% throttle that both reduces intake restrictions and increases engine load. Keep in mind, for a given rpm range load from throttle increase does not increase at the same rate as fuel consumption in a given RPM range.

    A more scientific explanation is that the higher your EFFECTIVE compression ratio the greater amount of power for a given amount of fuel and therefore more power and fuel efficiency for a given throttle position. For example, lets say 50% throttle position lets in twice as much air which is therefore compressed twice as much as the amount of air at 20% throttle. You might be accelerating at both throttle amounts, but for a given RPM range 50% is more efficient because the engine "sees" a higher compression ratio, you're basically doubling your EFFECTIVE compression ratio by increasing throttle which would increase fuel efficiency by itself even without less intake restriction.

    In another sense, you can increase fuel efficiency to an extent by increasing the GEOMETRIC compression ratio in your engine through head milling or thinner gaskets. The only reason we don't see extremely high compression ratios (14-1 and up) is because of preignition at such high compression ratios which would require very special and expensive fuels to counteract, and because the engine would wear out a lot sooner due to much higher loads. If those obstacles were overcome, one would find that as compression ratio increases, exhaust temps would decrease closer and closer to absolute zero, since more energy is being converted to motion rather than heat (would still have to deal with waste heat in the radiator though).

    This is also why turbochargers can increase fuel efficiency if sized to an engine right and driven for efficiency rather than power, they not only increase intake efficiency through wasted exhaust energy, but also increases the effective compression ratio. True, there is a slight amount of restriction to the exhaust but when driven right those restrictions are nowhere near as great as the gains from increased intake efficiency and compression ratio. The turbo basically has the same effect as an atkinson cycle engine, higher compression for a given amount of intake restriction.

    0
    None
    bmackinnon2ac-dc

    Reply 4 years ago on Step 6

    I must have forgotten my 2003 5.4L V8 F150 was a hybrid... I can get about 25 mpg on the highway, quite an improvement.

    0
    None
    pgan002

    4 years ago on Introduction

    To avoid stopping at a red light, try to arrive there just after it turns green again; if there is traffic stopped at the light, arrive just after it is leaving. This usually means breaking lightly, rather than coasting, as soon as the turns red. If you coast you might arrive too early and have to stop. But do not break too hard. Start breaking lightly and increase your breaking, always keeping your speed strictly above the speed required to coast to the light. Knowing the optimum speed comes with experience.

    1 reply
    0
    None
    LazyHpgan002

    Reply 2 years ago

    Another thing to add, if you keep an eye on the lights for the traffic on the other road at the intersection you can predict when your light will turn green. Where I live, if there's no turn lane light, my light will turn green about half a second after the other roads light turns green. If there is a turn lane light, and it turns green first for oncoming traffic, my light will turn green about 3 seconds after the last vehicle in oncoming traffic turn lane has entered the intersection. With that, I can start my vehicle moving just before the light turns green which also helps to avoid angering the drivers behind me with my slower acceleration.

    0
    None
    JustinC4

    3 years ago on Step 9

    Nope. This is false. I have an OBD Bluetooth connection to my tablet. This method sucks up fuel like a sponge. A nice slow acceleration is what is best, besides truckers (who have Standard Transmissions) do the same and they're all about conserving fuel. My car is an automatic.