Tag Archive 'ecodriving'

Jul 11 2008

Choosing Your Route for Maximum Fuel Economy

Good fuel economy isn’t all about driving an efficient car or modifying your car. One of the biggest limiting factors is your commute. The length of your commute isn’t something you can do much about, but there is almost always more than one way to get somewhere, as long as you’re willing to spend the time and effort to do it. This article will examine what makes a good route and how you can use different environmental factors to your benefit.

Before I get into techniques to save gas with your automobiles, it’s important to mention that if your commute is short and your climate is hospitable you have the perfect opportunity to get in shape. Your bike (or perhaps your legs) will become your best friends; saving you money and keeping your body in good health at the same time, what could be better? Besides people power, public transportation is a wonderful way to go, and will only get better as more people choose to ride. The park and ride is an especially attractive way to go when you’re commuting into a congested and polluted city.

That said, even the most diligent public transportation users or peddlers will need to drive every once in a while, whether it be to work, school, or out on the town. The first consideration is how many places you need to go. If it’s more than one plan your trip so that you’re looping around rather then zigzagging back and forth. For such trips you will not perform them enough to do a detailed analysis so you should abide by a few simple rules for best results (on average):
- Take the shortest path through all stops
- Avoid areas with heavy traffic (especially those that noticeably affect your driving patterns)
- Try to avoid roads with lots of stop signs and lights
Of course these things must all be balanced, but for most trips there are obvious options such as cruising down the interstate versus going through town.

Now, for those trips that are repeated with great frequency a bit of investigation is in order. By investigation I mean using your instantaneous fuel economy display to log your segment mileage over the course of several days so that you can compare different routes to see if there is on that gives consistently better mileage. However, be warned that you may chose a longer route with better mileage but still be burning more fuel! This is one of the reasons instant feedback is so important. If your vehicle was manufactured in 1996 or later check out www.scangauge.com or look online for a used model for sale. If your car is older but fuel injected email me and I will see what I can do to help you out with instrumentation (I have had great success with a device called the superMID in my 1991 CRX).

I’ll assume that most people are not instrumented yet and describe a few common scenarios and how they affect fuel economy:

1. Highway – In most cases highway driving will give you the best fuel economy you’ll see. There are some truly amazing fuel economy drivers that do much better around town than on the highway, but for most of us (myself included) the highway is a good place to be. But don’t forget: slow down! I drive 55 on the highway; that 10 MPH may seem like a lot but it does not extend the trip time very much and boosts gas mileage tremendously. Because aerodynamic drag increases greatly with speed, short of serious modifications to the car, slowing down will give you the biggest gain on the highway.

2. Around Town – This is the killer for most people. Frequent starts and stops, especially when coupled with a heavy foot, destroy gas mileage. Avoid heavy traffic, speeds that do not allow you to use your highest gear, and areas that do not lend themselves to safe coasting practices. Even if it extends your trip slightly the highway is preferable to 25 MPH speed limits and frequent, unexpected stops. However, if you have to drive through town try to stay in the highest gear possible. Your best instantaneous fuel economy will be achieved at the slowest speed you can go in the highest gear possible. When in a 30 MPH zone I regularly achieve 80+ MPG instantaneous readings because my engine is only turning over at 1,000 RPM.

3. Hills – It may seem counterintuitive, but hills can be a fuel economy driver’s best friends. Sure, you’ll get bad mileage up the hill, but as much as you go up you will eventually go down, and on the downhill engine off coasting will seriously increase your trip’s fuel economy. Some of the best fuel economy drivers live in hilly areas that allow them to have their engines on for only 50-60% of their commute, which allows them to achieve phenomenal mileage on their stock vehicles. When considering a hilly route it is best to plan stops that will be at the tops of hills so that you can coast while going up a hill and use less gas to get up to speed as you go down the other side. This may be hard to do but even a few stops can make a huge difference. Also, hills allow you to practice a technique called “driving with load.” DWLing means slowing down up the hill and regaining speed on the other side. This gives the engine a break when it’s working its hardest both as it struggles up his and as it struggles to regain speed.

4. Lights – In many places lights are timed in order to allow drivers who maintain the speed limit to pass through with limited obstruction. If you live in an area with timed light do your best to figure out the timing pattern and adjust your speeds in order to minimize stops. If a light is red it still might change based on the timing, so if you know it well enough you can plan your coast to coincide with the change of the light and the anticipated pace of traffic. When you do get caught in a red light, don’t take off, start up slowly and shift low in the RPM range. Chances are you will get caught by another soon enough and you will have wished you wasted less gas getting up to speed. Also, by accelerating slowly you leave space in front of you where you can coast while coming up to another stop. If you are right on someone’s bumper you have to yield to their reactions to upcoming lights. Another thing is that when stopping you should use engine braking as much as possible. When engine braking you are burning no gasoline and also reducing wear on your brakes.

So generally, to wrap it up, instantaneous information is necessary for a detailed analysis, but in the meantime anyone can improve their commute by taking advantage of existing circumstances or finding another route that is more exploitable. If the interstate you drive down has a side road with lower speed limits, take that, not only will you have a more relaxing drive but the lower speeds will improve your fuel economy. If you launch from the light to get up to speed just to hit the brakes for the next light, start up a little slower, shift lower, and coast to the next light. It’s all about attitude, once you stop rushing through things you won’t feel as rushed to get them done.

A friend, who I consider a good fuel economy driver, took the time to write up a few details of his commute and technique for the site. Please check it out here. Thanks alot, Phil.

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Jul 11 2008

EcoDriving for Beginners: How to Get Great Gas Mileage

In response to the recent hype surrounding hypermiling, I have been meaning to write this article for a little while. Finally I have been able to get around to it. Even if it is not in need of immediate revision, I intend it to always be an open project, so feel free to email me about it anytime.

So, what is hypermiling?
Hypermiling is a term that has been around for a while, I’m not sure how long, but it is generally though to have either come from or been popularized by Wayne Gerdes of cleanMPG.com. On ecomodder.com, the site that I frequent, a hypermiler is someone who acheives 20% above the combined EPA rating for their car.

How does one hypermile their car?
Well, it’s really not all that difficult. The range of hypermiling techniques are quite wide, from easy to very difficult. I’m hoping to address them all, but with the emphasis on the safest and easiest. I will also concentrate on some general tips to help people save gas. Hypermiling your car isn’t always the best way to reduce consumption!

Why should I do it?
There are many reasons that hypermilers do their thing: fun, challenge, environmentalism, and thrift. Depending on the type you are, you will find yourself gravitating to certain groups of techniques. I myself am an environmentalist, so you will see that showing up, be warned!

I will organize this as best as I can, but it may get a little confusing. Please bear with me and feel free to email if you find something amiss.

Section 1: Drive Less
I put this section first because it is the best way to reduce your gas consumption. If this isn’t an option, skip on down, but I think it’s well worth a look for everyone.

1 – Live closer to work
Living near your job will not only reduce your gas consumption, but will reduce stress, be safer, and give you more free time. If you’re spending 10 hours a week commuting, consider a change.

2 – Carpool
Carpooling will not only reduce consumption, but will reduce vehicle wear and tear, saving you a lot of money overall. Carpooling reduces road congestion, and really isn’t all that bad. Make a friend at work and commute together, it’ll be nice not to have to drive all the time!

3 – Bike
If you live close to work, biking can create entire days when you don’t even turn on your car. Even if you don’t live close to work, chances are that you live close to something you do. For those short trips to the bank, the post office, etc., consider getting on the old bike and getting a workout. You’ll enjoy yourself more and won’t be using any gas! Also, keep in mind that short trips are the hardest on your gas mileage. Eliminating all those below-average, around-town trips will boost your mileage without even touching your car.

4 – Combine short trips
You’ve probably heard this a million times, combining trips will save you gas, simple as that.

Section 2: Change your vehicle
Regardless of how you drive or how much you drive, getting a more economical vehicle will help. Check out the 100 Greenest Cars at Yahoo!

1 – Buy a smaller car
This is usually the cheapest and easiest thing. Think about how much size you really need and how often you actually fill your car to capacity. So what if it’s a little squished in the back when you have to haul extra people? That’s never hurt anyone in the past. Moving to a smaller vehicle will save you money in just the vehicle cost, let alone the fuel savings. Just make sure your smaller car isn’t a sports car!

2 – Buy a hybrid
They’re all the rage right now, and for good reason. Honda and Toyota hybrids can regularly dominate their non-hybrid competition. For a bit more money, you get all the comfort of a bigger car and all the economy of a smaller car. Hybrids are generally some of the best cars on the market for pollution and reliability. Don’t let the skeptics get you down about battery replacements and pollution, these claims are greatly over blown.

3 – Buy a motorcycle
Though a motorcycle would be difficult to use as a sole means of transportation, small motorcycles such as the Kawasaki Ninja 250 can be had for about 2000 dollars and will return fuel economy great than 75 MPG and great performance. If you do go this route, don’t forget your gear and your safety course!

4 – Buy a scooter
Just like number 3, but even better mileage! If you live in the city, this is the perfect solution for a lot of people. Honda currently makes the best scooters out there, and a Honda Metropolitan will return over 100MPG. Just don’t buy a 2-stroke and remember the gear and the safety course!

Section 3: Change your driving habits
This is the most important thing you can do when working with an existing vehicle. There are a ton of strategies, but I will try to simplify them to serve as an introduction.

1 – Get instrumentation
The most important thing you can do is get some instant feedback so that you know what’s going on with you car. If you are driving an OBD2 vehicle (1996 and up), go to www.scanguage.com and pick yourself up a Scanguage II. You can also find them on ebay for a little cheaper, but they are indispensable. For older, fuel injected cars, check out the SuperMID. It is more limited in terms of compatibility, but very worth it if you are compatible.

2 – Slow down!
Air resistance increases exponentially with speed, so slow down! The difference between 55 and 75 is astronomical.

3 – Plan your route
One of the easiest things to do is choose a better route to work. In many cases, you may find that you use less gas but get lower mileage, or go further but use less gas, depending on which route you pick. This is why tip 1 of this section is important. Check out this article for more information.

4 – Stop idling
When you idle, you are getting 0 MPG. Idling the car in the cold does not help warm it up, it actually takes longer. Just drive gently after starting up.

5 – Avoid rapid acceleration and hard braking
These sort of actions waste gas. Instead of braking hard, coast from as distance. Use your brakes as sparingly as possible. Also, be aware the slamming the gas will only dump more fuel on than is necessary. Conservative acceleration will generally return the best fuel economy.

6 – Anticipate changes in traffic
If you know that a light is going to become read or turn green, slow down in advance and give it time to do so rather than gunning the gas up to the stop. In heavy traffic give yourself a bit of space before starting up, try to keep moving slowing rather than alternating between fast speeds and stops. This is one of the best tips for driving, as it will prevent you from making many unnecessary stops.

7 – EOC (Engine Off Coast)
Engine off coasting is the way to go to increase fuel economy to astronomical amounts. This is very difficult and can be unsafe, so be very careful when using it. Also be aware that long EOCs can reduce catalytic converter heat and increase emissions (though the time period or relative emissions increases are unknown.
Before EOCing, you need to be aware of how your car will preform under the circumstances. The basic drill is to put the car in neutral, turn the engine off, and turn the key back to run (to give you the use of the speedometer as well as the ability to turn the wheel). EOCing will cause you to lose both power steering and power brakes. You will have a limited power brake reserve, but this depends on each car.
For your first EOC, find a deserted road with a long open stretch and then key off, turn to run, and begin coasting. While coasting, test your steering and your brakes. If they do not feel comfortable, don’t EOC! You don’t want to risk anyone’s life in this pursuit. If steering is okay and the brakes work well, you are ready to EOC in normal driving. Just remember to be very alert and not to EOC in environments likely to have unexpected occurrences. Stay safe!

8 – Draft
On the highway you will notice that SUVs are basically moving walls, pushing all the air out of the way. If you get in behind one, air drag will be cut astronomically. Now, don’t get too close, try to leave 100 feet, or else the trucker will become angry and neither of you will be safe. Even at 100 feet drafting has benefits.

9 – Pulse and Glide
P&G is an interesting technique, taken from the hybrid drivers, which involves alternating EOC and acceleration. P&G is most effectively done at slower speeds, where air drag is not as much of an issue. To P&G you pick a target speed (say 40) and accelerate past it (to 50) and EOC until your speed drops (to 30), you then start up again and accelerate back to the upper target. Rinse and repeat for awesome mileage. Note: This is best done when no one is around and is very annoying to keep up!

10 – Driving with load
In hilly terrain, it can kill FE to be constantly gunning it up hills. DWL involves picking a fixed throttle and slowing down up hills and gaining speed down. Rather than holding speed, you are holding the pedal. This is a very affective way to deal with hills, though you often will need to bend the rules to not slow down traffic too much.

11 – Reduce engine loads
High fans, loud stereos, A/C, and heat add load to the engine and reduce fuel economy. It is much better to roll down your windows than to turn on A/C in almost any circumstance, so keep this in mind. A/C can reduce fuel economy 5-30%.

12 – Turn of 4WD
If you can, turn it off when it is not necessary, it increases driveline losses.

Section 4: Modify your vehicle
Vehicle modifications are some of the most difficult and hardest to quantify changes you can make. Some of them are great, others might seem like more effort than they are worth, and some will be just too hard to do. Pick and choose.

1 – Swap the engine
This depends greatly on your mechanical ability. If you can do it, pick out an engine, and throw it in. This is akin to getting a new car and can give you huge boosts in mileage. I won’t go in depth, however, because I’ll assume that if you know how to do it you can pick out an engine. Perhaps in a later article I will detail the options for Hondas. (Feel free to bug me if you want it done.)

2 – Swap the transmission
Very similar to the above. An auto to manual, like I did, will realize the biggest change. I picked up about 50% on my mileage with this swap. Figure out the gearing on various transmissions and see what suits your needs. You can also swap gears around from within transmission, but then it just gets more complicated! Check out this link for more.

3 – Increase tire pressure
This is one of the easiest ways to increase mileage. I currently have my 44 max psi tired inflated to 50 psi. This doesn’t mean that you should do it, but it has been done by many people. When overinflating, inflate a bit at a time to test handling and feel before you settle somewhere comfortable. Be prepared for a bit rougher of a ride, but you will see the fuel economy increase!

4 – Warm air intake
The WAI will not work for everyone, but it is worth noting because it is a very good mod for Saturn owners. For whatever reason, Saturns really respond to warm air intakes, so take advantage of it of you can. A WAI is generally constructed by extending the stock intake to suck air from closer to the exhaust manifold (where air is warmer). Once again, experiment before you finalize anything.

5 – Block your grill
The air drag caused by the radiator is rather large, so grab that corrugated plastic and block your grill. Be careful to make your first block easily removable and watch the temperature gauge to make sure you don’t overheat. It’s important to find a balance between cooling and aerodynamics, even a partial block will help.

6 – Rear wheel well covers
These snazzy looking covers will help smooth airflow across the car by closing the rear wheel wells. These are affective, though not mind-blowingly so. A must do for anyone with a lot of highway driving or someone interested in aero mods.

7 – Undertray
Covering the entire bottom of the car with corrugated plastic will reduce air drag caused by the roughest surface on most cars. This mod is difficult mainly because you have to get under the car and work on your back securing everything. If you do this, make sure to leave easy access to oil and anything else you might need to get at normally.

8 – Take off the alternator belt
This is a pretty hardcore thing to do, but pays large dividends. By removing the alternator belt you disable the alternator and remove all electrical load from the engine. This means that you will be running down the battery constantly, so to do this you need to minimize electrical loads and run a battery charger at home to keep the battery topped off. There is also the possibility of running a solar car battery charger, though I haven’t heard of anyone experimenting with this yet. Make sure to only remove the belt in case you need to reattach it at some point to deal with rain or darkness!

9 – Replace your radiator fan
If your fan is belt-driven or otherwise inefficient, pick up a new, electric fan to help reduce engine load. This is an especially good modification for those with belt-driven fans, and can save quite a few horsepower.

10 – Remove power steering
For many smaller cars, powering steering is more of a luxury than a necessity. My CRX does not have it and I’ve always been glad of that fact, it makes me feel more connected to the road to have manual steering. That being said, for cars with power steering there are often ways to disable it or to convert the car to manual steering. Also, electric power steering has become an option in recent years. Power steering is just another one of those little things that will rob you of a few HP here and there.

11 – Boattail
This is further down because it is difficult to do, even if it is good for a lot of improvement. A boattail reduces drag caused by turbulence at the rear of the car, which accounts for a large amount of a car’s aero drag. Check out Basjoos’ car in the gallery for some interesting ideas.

12 – Low rolling resistance tires
Much like increasing the tire pressure, LRR tires reduce rolling resistance by using a harder rubber material. They are more expensive and harder to find, but keep them in mind next time you’re shopping for a car.

Good luck and happy hypermiling! Don’t forget to make suggestions.

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Jul 11 2008

Hypermiler Profile: Darin Cosgrove

Published by Benjamin Jones under EcoDriving,Interview

Name: Darin Cosgrove
Occupation: Underemployed Tinkerer
Weapon of Choice: 1998 Pontiac Firefly

Much like our first profile, Darin is an icon on the forums at ecomodder.com. For months he has inspired many to stretch thew limits of their own fuel economy. He’s a pioneer of controlled testing and a believer in aero mods. Darin’s a pretty cool guy and also a great resource. This site is inspired by him and his efforts with his own site www.metroMPG.com.

When Darin first came to the ecomodding game he thought that a consistent 60 MPG would be awesome. Now that he’s posting 80 MPG tanks and 130+ MPG segments, the story has changed just a little bit. Most of Darin’s improvement is a result of driving techniques and some modifications. With his scangauge he practices nearly every driving technique known, and does so well. You can check out a brief summary of these techniques here. Aside from driving, Darin has swapped in the taller transmission from the 1.3 liter Metro/Firely/Swift and done several aero mods (most notably rear wheel skirts and grill block.

For Darin is doesn’t stop with great fuel economy; currently he is in the process of building a commuter EV (electric vehicle) out of another Metro. He and his partner in crime, Ivan, are hoping to complete the project for mere pennies (~1500USD is the goal, I think) and while it will not be a road warrior it’ll get the job done. At the time of writing the two are working on coupling the electric motor (donated from a forklift) to the Metro’s stock transmission. While progress is slow the result should be great; I’m looking forward to profiling it on this site!

Darin has certainly been instrumental to my quest for great gas mileage, and I’m glad to have access to his thoughts and postulations on a plethora of issues. This interview is a compilation of the questions that I asked Darin and those that another gassavers member, named Rick (RH77) asked a while back. So thanks to both Darin and Rick for this.

Ben: When did you begin hypermiling?
Darin: I taught defensive driving as a part-time job while I was going to
university in the early 90′s.  Part of my training for that job was to
research and present a seminar to my fellow instructors.  I picked
“economy driving”.  Proving the best way to learn is to teach, I’ve had
the bee in the bonnet ever since.

Ben: How have your goals changed?
Darin: In two ways:

First, I have a habit of resting on my laurels until someone else at GS
starts posting some amazing numbers, and that often spurs me on to
re-test myself to see if I’m fully tweaked, skill-wise and mechanically.
People like basjoos, Dan, and now Larry cause me to re-evaluate &
re-set goals on a regular basis.

Second, the more I play at this, the “smaller” my goals get – due to
diminishing returns.  I achieved the big savings early on.  I’m tickled
to see a mechanical/aero mod than nets a couple of % improvement, or a
tank average that’s a little bit higher than the last.

Ben: If you could have any car, what would it be?
Darin: One that doesn’t exist yet: a very aerodynamic plug-in hybrid.  And it
would still probably sit parked most of the time while I ride around on
my beater 10-speed bike.

Ben: What are your views on alternative fuels?
Darin: Not overly educated on the topic.  I’m on the fence with Ethanol,
because the evidence seems split on whether it’s energy positive.  Even
if it were vastly energy positive, the efficiency nut in me still
cringes at the thought that its reduced energy content is going to drop
my absolute FE numbers, which is just silly.

Ontario is going to 5% mandated ethanol in the not-too-distant future,
so I’ll have to lobby for a fudge factor at GS to compare ethanol to
non-ethanol cars.

I love the concept of WVO biodiesel.  Yes, my dream car would have a
small clean diesel as its ICE component, so I could bug the local chip
wagon guy for his used fry oil.

Ben: What motivated you to make your landmark 133MPG RT?
Darin: Landmark, eh?  Well, a number of things.  Larry’s recent performance,
first of all, made me want to test my (& the car’s) limits a little
further.  Also it made me curious what the car’s ultimate limit is
(still haven’t found it – probably won’t this year with recent autumn
temps).  Plus, I wanted to put my high numbers in context by showing the
(low) average speed I had to drive to get them.  I have a feeling people
see high numbers and go “wow!” without always being aware of the speeds

Ben: What will win, hydrogen or EV?
Darin: For me?  EV!  Not sure about everyone else.  Then again, since the
hydrogen cars are all EV technology anyway, with a fuel cell plugged in
where a good battery should go.  It’ll make doing EV conversions for
future tinkerers easy!

Ben: What are your three best driving tips?
Darin: Don’t.  Slow down.  Coast a lot or CODFISH.

Ben: How about best modifications?
Darin: Believe it or not, the single biggest gain I’ve measured so far was by
unbelting the alternator for local driving and going with solar/grid to
recharge the 12V battery.  Cruising FE is 10% higher when I do that.
Cumulatively, the 5 different aero mods I’ve tested just surpass that,
at around 12% (@ 90 km/h).

Ben: Is there an end in sight to your skyrocketing fuel economy?
Darin: See above, re: diminishing returns. :)

And now here’s a bit from Rick’s interview, we both asked the same question about Canada/US, so there you have it. Thanks again to Rick for letting me use this.

Rick: What is it for you?

Darin: No simple answer, it’s all kinds of factors: I’m a kind of minimalistic person to begin with; saving money, conserving resources; it’s a kind of game – through through gassavers it’s turned into a friendly competition (where before it was a game played against myself); obsessive compulsion; pick an answer!

More personal insight: one of my favourite non-car-related hobbies is sailing and sailboat racing.  It’s very similar to the whole gassavers mentality: making the most of a finite resource (the wind), continually using your wits to judge the situation, trim the sails and watch for opportunities in the air, current and the fleet to improve efficiency (make the boat go faster).  It’s a very similar mind-set to hypermiling a car.

As for environmentalism… it’s not a huge driving factor.  But I do tend to ride my bike more than drive locally in the summer.  Even the forkenswift project is less about making an environmental statement and more about the coolness of the idea overall and the technical challenge.   (Though I’m sure i’ll get all smug about the environmental reasons when we’re done!)

Rick: Secondly, discuss the Suzuki-Clone experience you’ve had.

Darin: These cars were always on top of the fuel economy charts, and I had actually wanted one for years.  I put off trying a suzukiclone for a number of reasons, one of which is my old accord kept ticking along for 8 years.  Also, they have a stigma – with two elements really: 1) the notion that being cheap, they must be junk.  that turned out to be untrue – it’s actually one of the most reliable used cars of the many that i’ve owned; 2) the social stigma – they’re the antithesis just about everything that’s communicated in mainstream car marketing (ie. irrational, emotion-based messages).  They’ve even been mocked on the Simpsons TV show – can you guess which character owned a Metro?  (Answer at the end).

My current suzukiclone is a true “barn find” – it was bought new by a little old lady who fell ill within the first year, and so it was parked in her family’s garage … for the next 7 years.  When I bought it last november (firefly #2), it had just 2,400 km on the odometer.

There’s no getting around the fact it’s a small car.  On the freeway, you don’t sit back and shut off the brain if it’s windy or there’s any truck traffic.  Then again, i owned a motorbike… so it’s all relative. The first time my dad saw the car, he said (and BTW, this is the single most common response to the car): “Is it safe?”  (My answer: It’s safer than a motorcycle!)

I’m used to it now.  When I drive a larger car, I’m surprised by all the “extra” mass and power people are “wasting” fuel on.  (I had this reaction driving a friend’s altima yesterday!)  If I were to take a cross-country trip, I wouldn’t hesitate to drive the blackfly.  If I could buy a smaller car, I probably would.

Rick: Maybe we could compare and contrast cultures and how we can learn from each other.

Darin: Not sure what to say here.  car-wise the big difference between us is Canadians’ affinity for smaller cars.  Maybe we’re more practical? Maybe we’ve got less disposable income.  Gas has always cost more here, due to fuel taxation.  Maybe it’s a cultural thing – we don’t have a home-grown auto industry, and the American psyche is somewhat tied to (big) detroit iron.  From the outside, I get the impression that Americans equate “small” with “foreign”, so buying big iron is in itself a kind of patriotic statement.

Thanks to Darin and Rick for this, they’re both great and I hope everyone can learn just a little bit from this. Also, check out www.metroMPG.com!

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Jul 11 2008

Acceleration and Fuel Economy Tested

One thing that has been floating around the heads of many users at www.ecomodder.com for a long time is which method of acceleration proves most effective for fuel economy. It would seem logical that the slow and steady would prevail, but there is also the argument that a quick sprint to cruising speed is best because it gives more high FE cruising time. Even though the acceleration would use more gas it would be balanced by the better FE from cruising or engine off coasting. I chose tonight, the last night I would have my car before heading off to Dartmouth College, to test this idea.

Before getting into the results the test route and procedure needs to be exhausted in order to understand what was actually going on. After warming up the car on the test route I got down to business. There were two theories at test here and I will now describe how each of them was applied in my testing:

  1. Slow and Steady – For this I used my regular acceleration patterns. I gave very light throttle, shifted into 2nd at 1500 RPM, 3rd at 1500 RPM, 4th at 1250 RPM, and 5th at 1250 RPM. From this point I accelerated in 5th (beginning at 1000 RPM) up to 40 MPH until I hit on of the designated engine off coast (EOC) points. If I was not at a stop and simply pulse and glide (P&G) coasting I would bump in 5th and get back up to speed in the highest gear possible at a slow pace.
  2. Jack Rabbit – Because extra throttle doesn’t do much at the low RPMS I usually accelerate at I took first gear to 2500 RPM, second to 2000 RPM, and 3rd to 2000 RPM. At this point I shifted straight into 5th as I was already going the mandated 40 MPH for the test. I gave the car 50-60% throttle during these periods of acceleration.

Here’s an edited version of the course I tested this on. It made for a total of 4.79 KM from start to finish. Each number on the map will correspond to a note discussing driving tactic or course layout:

**NOTE: Traffic was not an issue at this test was conducted at midnight on empty roads** On that note, here is a point by point description of the trip:

  1. Start point, stop sign. Accelerate to 40 MPH
  2. EOC to point 3.
  3. Traffic light but I stopped each time to keep it consistent. Accelerate to 40 MPH.
  4. EOC to point 5.
  5. Stop sign, accelerate to 40 MPH.
  6. P&G to 30 MPH.
  7. Bump start and acclerate to 40 MPH.
  8. EOC to point 9.
  9. After taking curve at 25 MPH bump start and accelerate to 30 MPH.
  10. EOC to point 11.
  11. Bump on for ~100 yard then EOC to Stop/Start.

Each of the EOCs was begun at the top of a hill or to a stop (the only flat EOC was to the stop). It was odd that each leg of the trip had a hill right in the middle, but that’s how the cookie crumbles I guess.


Ah, the fun stuff, finally! I won’t say I was surprised terribly, but a little bit. The difference isn’t much, but heck, it’s consistent.

Slow and Steady Results

Test Number 1 2 3
Time 6:28 6:23 6:32
Engine On % 53 51 51
Engine On FE 34.41 MPG 32.31 MPG 32.47 MPG
Fuel Used .228 L .236 L .234 L
Segment FE 65.53 MPG 63.30 MPG 64.12 MPG

Jack Rabbit Results

Test Number 1 2 3
Time 6:16 6:24 6:27
Engine On % 50 49 49
Engine On FE 33.06 MPG 32.22 MPG 32.49 MPG
Fuel Used .226 L .226 L .225 L
Segment FE 66.29 MPG 66.41 MPG 66.54 MPG

There is certainly no big gap between these two sets of results, but I believe they are consistent enough to draw a conclusion. The average of all the slow and steady results was 64.32 MPG while jack rabbit acceleration yielded an average of 66.42 MPG for a difference of 3.3%!

I attribute this difference to the increased amount of EOC available with the jack rabbit acceleration. I believe that if there were more distance on each leg the difference would be even greater, but that test will have to wait for another time!

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Jul 11 2008

Basic Fuel Economy Driving Techniques and Instrumentation

There’s been a lot of talk about how important instantaneous feedback is in achieving high fuel economy, but what role does it really play and how can it be most effectively used? Hopefully we can get into that a little bit here. Firstly you should not that this article will be focused mainly on using the SuperMID since I don’t have and can’t use a Scangauge. If your car is 1996+ you can check out there Scangauge at their homepage, www.scangauge.com. Regardless of the device this article will be written in order to discuss how it is used to help you get better fuel economy.

Take a look at this little diagram that I made of the main screen of my MID:

Instantaneous FE – This tells you the fuel economy you are getting at the very moment and has little bars that fill up the top-middle such that more bars equal greater fuel use and so on. This is highly variable but you will use this feature when featuring the gas, driving with load, and a whole host of other things that are based mainly around a target fuel economy.
Average Speed – This gives you the average speed for the trip, pretty straightforward. You’ll notice, however, that if you’re repeating a specific trip a slower average speed will generally correspond to a higher trip fuel economy.
Injector Pulse Width – Raw data about how long the injectors are open for. This is a good indication of load in my experience as it takes the speed component out of the FE equation and tells you directly how much gas is going in there.
Distance – Records how far you’ve traveled since resetting the section you’re viewing.
Fuel Used – Records how much fuel you’ve used since resetting the section you’re viewing.
Percent Distance with Engine On – This is one of the neater features of the MID. Because it was originally designed for use with the Toyota Prius to allow FE readings higher than the stock computer could record it was also programmed with a function that records what percentage of the distance traveled is done so with the engine on. In the case of the Prius this would be a ratio between the combustion engine and electric motor, but for us it is a great measure of the use of engine off coasting and engine braking. It records any amount of distance traveled without the injectors opening as time with the engine off, and is a very helpful tool to compare engine off coasting’s effect on fuel economy.
Engine On FE – This is another Prius feature that is very interesting to compare engine efficiency with efficiency of driving technique. You can see that the engine on fuel economy is lower than the trip fuel economy (the difference translated to about 3 MPG) so that even on this very short trip where I didn’t do very much engine off coasting I have reaped the benefits!
Trip FE – Trip FE is either the most important or second most important function of the superMID. Trip FE will allow you to pick routes to work/school, help you figure out if your driving skills are improving, challenge you to do better on every drive, and let you test modifications you’ve done to the car. Most of the rest of this article will be based around the use of trip FE.
Last KM FE – The last KM FE is just that, the FE that you’ve managed over the last KM of distance. This section evens out some of the spikes of the instantaneous FE and alerts you to the fact that you might be getting bad FE due to a slight grade or unnecessary throttle pressure. It’s also rewarding to see it pegged at 99.99 KM/L after a > 1KM engine off coast.

SuperMID Daily Driving Tips&Tricks

  1. Begin with the most fuel efficient route – Why spends weeks fine tuning your trip to work when in the end you could’ve been getting better mileage on some other route? Before you spend all your time trying to max out a certain route experiment with others to help you find out which one is really best. Don’t go be straight trip FE, use the total fuel used section to see where you’re actually using the least. Make sure that you give each route a fair shake and try to collect data from days with similar weather patterns. Also, be aware of the hypermiling potential that one route might have over another; if one has a steep hill with a gradual downslope and the other has a gradual hill with a steep downslope you are more likely to succeed with the first option. You will spend less time going up the hill and more time coasting your way down. For more information on route selection check out this article.
  2. Set goals – Before the discussion on actual driving tips, you need to remember to set goals, both for tanks and individual trips. The most important thing about goals is breaking them, because every time you smack through a milestone you will be motivated to set another one and break that one too. Start of realistically though. If you’ve been getting 35 MPG say you want to hit a 40 MPG tank and 50 MPG segment, not too far out of the realm of possibility but certainly beyond what you’ve been getting.

    Another important method of goal setting is to make each particular milestone in your drive a goal in itself. For example, when I drove to school I would do whatever I could to get to 30 MPG before leaving the developement. This was rather difficult as there were many stops and it needed to be done on a completely cold engine, so the challenge was ever present. However, I knew that if I could accomplish this I was set up for a good day in terms of fuel economy. I would also set goals for FE when entering the highway, leaving, and passing other certain major changes in the trip. In this way I could tell whether or not I was on course for my overall goal and could thusly adjust my driving habits.

  3. Feather the gas – This technique is extremely important if you want to squeeze ever last bit of gas mileage out of your car. Generally when you drive you’re giving more throttle than you need to to maintain speed or you’re constantly and very slightly accelerating. With the superMID you can vary your throttle pressure until you’re at your very lightest point while maintaining speed and you’ll actually see the increase in fuel economy. Even with this knowledge now I cannot properly feather without the MID, it’s just crucial to be able to see the slight differences in pressure and road grade that you would never notice without instantaneous feedback. The MID challenges you to milk ever last MPG from your drive, even when you’re just cruising.
  4. Slow down – Speed kills! Aerodynamic drag increases greatly with speed, not to mention engine RPM and load. If you can manage it go 55 on the highway or avoid the main highway altogether. You’ll see a huge savings from 65 to 55 MPH, especially if you have short gearing that leaves you cruising at upwards of 2500 RPM.
  5. Engine Off Coast – Engine off coasting is just what it sounds like. When you come to a stop or a span where you can coast without losing speed you shut the engine down. To do so flip the key to I and allow a few seconds before switching back to II. This will disable power steering (if you have it) and your power brakes will only have enough charge for a few stops. Make sure to practice EOCing in an area where you can safely test you car’s reaction to this technique. If you’re EOCing to a stop simply stop and when you’re ready to go key back on. If the EOCing is part of a coast simply key back on when you’re ready to restart or bump start by letting the clutch out while in gear to restart the engine.
  6. Pulse and Glide – Perhaps the most intriguing and beneficial of all the FE driving techniques, P&G involves two basic steps. The first is a moderate throttle pulse to a target speed and the second is an engine off coast back down to the lower target speed. The idea behind this technique is that normal internal combustion engines are inefficient during normal cruising but more efficient at moderate throttle. When that moderate throttle is couple to the infinite FE of EOCing you will end up with a higher average FE than if you simply cruised at a steady pace. This is most easily accomplished at low speeds because there is less aerodynamic drag than would be present at higher speeds. So with a low speed P&G you can really increase the distance of your glide. Of course all the same issues apply with P&G that do with EOC, so practice in a safe area and make sure to measure your non-P&G FE first so that you can compare and refine your technique.
  7. Drive with Load – When DWLing you do your best to maintain fuel economy when encountering hills or small inclines. In normal driving you would attempt to hold 45 MPH by increasing throttle pressure, but when DWLing you pick a target fuel economy level and allow yourself to lose speed while going uphill in order to not lose fuel economy. You may then pick up speed on the downhill where you can speed up quickly and without greatly damaging fuel economy. DWL will greatly aid fuel economy but depending on the speed and size of the hill there is a limit to its benefits. If you’re in a trafficless area and willing you can bleed off as much speed as you want, but while in traffic you have to consider potential safety issues during DWL.
  8. Parking Tactics – Always park in the highest spot you can find. If your driveway at home has a slope, use it. Roll out into the road before starting and try to use some of that momentum to begin your drive. In parking lots back it in when you park. Reverse is a killer but using it on a warm engine is better than having to reverse out of a spot on a cold engine. If possible find a gap where you can pull straight through and be facing forward in the space so that you do not need to reverse at all. When entering a parking lot scout it out immediately and try to find a spot in a location that you can coast to without using any extra gas. If you can shut off the engine entering the lot and coast into your space you’ll have saved a lot of gas that would normally go to first or second gear navigation.
  9. Braking (or lack thereof) – Using the brakes is an awful waste of momentum, try to avoid it at all costs. Anticipate traffic flow and coast to a stop rather than following traffic and braking with it. If you coast early many times traffic will pick up by the time you reach the clog and you will not need to brake at all. Take curves as quickly as possible while maintaining safety. If possible coast to the turn so that you do not need to brake at all. When approaching lights coast first, engine brake second, and then brake as a last resort. If you time things just right you can make most lights and turns without using the brakes at all.

Well, now that that’s over with, I should describe some of the other functions of the superMID. As you may have noticed in my picture there is an “A” by the engine on percentage. This corresponds to a trip stored within the superMID, there is A, B, Start, Tank, and Lap. A and B are just arbitrary storage containers, Start records everything since the beginning of the use of the MID (unless it is reset), and Tank records your statistics for the tank. The Lap function stores 20 different laps and is very helpful for testing as you only need to push one button to switch to a new lap. It also allows you to compare the current lap FE to the last lap without switching menus.

Now that you know the tips, tricks, and function of the superMID, go out and get yourself one! If you’re seriously interested contact me and I will put you in touch with Yoshi, the maker.

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Jul 10 2008

EcoDriver Profile: Dan Kroushl

Published by Benjamin Jones under EcoDriving

Name: Dan Kroushl
Occupation: Professional Slacker (You don’t really need to know, do you?)
Weapon of Choice: 1992 Honda Civic VX (Stock)

For months Dan has been a bit of an icon around ecomodder.com and I thought it fitting that he receive proper mention here and he has driven so many people to look for new heights in their quest for gas mileage.

When Dan first came to the ecomodding game he was making 50 MPG tanks in his Del Sol S. This doesn’t seem like much now, but at the time it was amazing. In the end Dan managed to hit mid 60s in the Del Sol and is now pushing past the 70 MPG barrier in his Civic VX.

You might not know Dan, but he’s already become a mini-star on the internet for his contribution to the quest for fuel economy. You can check him out on the Toyota website here where his efforts with four partners set a world record for fuel economy. This has since been topped, but who knows how long any of these records will last?

However you look at it, Dan’s really paved the way for great fuel economy; first in the Prius and now in his fifteen year old Civic VX.

In order to share a little bit about his technique with everyone, I asked him a few questions about his adventures with hypermiling.

Ben: How did you first learn to hypermile?
Dan: I started hypermiling in 1985 when I bought the CRX HF. I did just what made sense to do to save fuel. Turns out that those things match up pretty well with what now turns out to be accepted hypermiling techniques.

Ben: What difference has the superMID made in your driving practices?
Dan: It helped the Prius Marathon team learn to go from 107ish to up to 120MPG. It (and the scangauge) is the single best investment in FE improvement. I guesstimate that it was good for 20% improvement in the Del Sol FE, from 55 to 65 MPG.

Ben: How does your Civic VX compare to the Prius in terms of comfort, usefulness, and FE?
Dan: The VX can carry up to 5 passengers, but more cramped than the Prius. The Prius has much more cargo room, quieter, smoother ride and has A/C. The VX gets much better highway FE and similar city FE if driven properly. The VX was about 1/10th the price of the Prius.

Ben: Do you see any obvious advantages or disadvantages to driving the VX?
Dan: The VX is the highway cruiser. The Prius is much easier to drive in the city, EV mode being very useful.

Ben: Do you feel cooler when you drive the Honda?
Dan: I feel like a geek in both. But if I had the rust repaired and a nice new shiny coat of red paint, I would feel cooler in the VX.

Ben: Could you give us a short description of your route and common segment FE?
Dan: My commute is 40 km (25 miles) each way. Ten km city type driving, then 20 km highway in 45-55 MPH zones and then 10 more km of city type driving. Lots of hills. [Dan regularly gets 75 MPG on his commute.]

Ben: What are your three biggest FE driving tips?
Dan: Get a SuperMID or Scangauge, drive such that you don’t need to use your brakes, leave early and take your time, the speed limit is the maximum, not the minimum.

Ben: Three biggest modifications?
Dan: SuperMID/Scangauge, LRR tires, full belly pan.

Ben: For all those driving a non-FE car, how hard was it to pick up the VX?
Dan: Just watch ebay for VX’s. You want a 49 state version, not the CA version. Be prepared to do some repair work to get it in top shape. Most likely it will need an O2 sensor for $315 at Autozone [You can get these much cheaper if you have a warning that you will need it!]. Other likely repairs will be axle replacement and front rotors as they tend to warp. Most have rust at the rear wheel wells but not to worry, FE isn’t effected that much by rust. Don’t be too concerned about high mileage, Honda’s last forever. If you do find one on ebay, try to get a test drive before bidding.

If you can’t find a VX, a CX will do quite nicely.

For those interested, here’s his gaslog with the VX:

Thanks very much to Dan for sharing with us, hopefully his example will lead us that extra little distance to superb fuel economy!

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