Instructables

Vehicle efficiency upgrades: 30+ MPG in 2.5ton commercial truck

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Truck MPG.gif
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[note:  new video has been added on step 1!]
[note 2: Most of what I write isn't relevant to Instructables.  My main blog is here: biodieselhauling.blogspot.com]

[note 3: Also save energy at home.  See my energy guide: instructables.com/id/Not-your-average-save-energy-advice-use-less-en/ ]

Go 50-100% farther on a tank of fuel.

Due to its size and weight this truck is considered a commercial vehicle and is exempt from even light-truck CAFE standards. Even so, with the modifications I have made, I am getting higher mileage than CAFE standards for 2009 cars.

I read an article in Mother Jones Magazine about Wayne Gerdes, mileage champion, and was inspired. I have read that people tend to get between 10 and 16mpg on average in the same truck I have. I was getting around 15. After the mods described here, on a recent tank I got 30.28mpg.

The best thing to do is to not drive at all. Ride a bike, take the train, carpool.
If you do drive, buy the absolute smallest car you can. If you only need a big vehicle occasionally, rent one.

I bicycle or use my 70mpg 250cc motorcycle for personal transport, but my truck still gets a lot of miles, so I wanted to make it as fuel efficient as possible.
I use this truck for work, moving up to 3 tons of soil or broken concrete, entire 1 bedroom apartments worth of belongings (including furniture) in a single trip, etc.
I also need something with enough power to move my 7500lb RV trailer (which is also my home - a very efficient way to live: I use as much electricity in a month as the average American home uses in one day)

Most of these steps could be done to any vehicle, increasing mileage from 50% to 100% or more.
 
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roosta5 years ago
you should never shut off the engine whilst moving as it disables the power steering, and in some (especially older cars) also locks the steering rack, so you cant turn. steering locks are security devices fitted to cars to prevent theft.
KaydenST roosta15 days ago

He took out his power steering. Interesting thing about the steering though.

JacobAziza (author)  roosta5 years ago
I don't use the key to shut the engine, so the steering lock never engages. Power steering is really unnecessary at speed. If you drive a truck with no power steering, the only time you notice it is when parallel parking. The power brakes on the other hand.... (an electric vacuum pump for the brakes is my next step)
JacobAziza (author)  JacobAziza5 years ago
electric vacuum pump has been installed. Brakes now function exactly the same whether the engine is on or off.
JacobAziza (author)  JacobAziza5 years ago
Manual steering gear is now also installed
mrcllane5 years ago
Shutting the engine off and costing is a good way to wreck. A lot of vehicles need the engine running for the brakes and steering to work.
480-ferrari-crash1.jpg

He said he had electric brakes and he took out the power steering, so it makes no difference.

Forgot to mention using your engine for braking.  When your wheels are driving the engine, it's not burning gas, and you save money on brakes.  Of course, you need a manual transmission for that.

   I coast with the engine off all the time, but safety first (I use the clutch as a failsafe way of coasting):
(1)  Normally, I coast with the clutch pushed in, transmission in gear, and the switch on.  That way if a situation arises, I can pop the clutch, start the engine and be under full power in a split second.
(2) for long, clear coasts, I leave the switch off, with the clutch pushed in & transmission in gear.  That way if I start to lose power steering (and brakes) I can briefly engage the engine (in high gear) to restore the vacuum. 
   Losing vacuum In my hilly topography is rarely a problem: by the time I start to lose steering, I have either slowed too much and need to restart the engine, or have accelerated too much and need to slow down by engaging the engine (which restores the vacuum, even if off).
   (3) I wouldn't do this with an automatic.  
  (4)  I suspect that popping your clutch to start your engine can cause a voltage surge which could burn out some electronics if your voltage regulator is defective (This seems to have happened with one of my cars).

Engine off coasting with an automatic can and usually will damage your transmission and possibly your torque converter. The ATF pump is almost always on the input shaft(from the engine and torque converter) and will not pump unless the engine is running (which is why you can't roll start an automatic (unless you have a car where the ATF pump is on the output shaft as with the old Chrysler 300's)). No fluid flow and the torque converter will drain of fluid and COULD be damaged (though not as likely since it drains when you park the car and shut it off, then refills when you start the engine) and the trans won't get proper lubrication, causing damage. This is why you are not supposed to tow an automatic with wheels on the ground
nerys denswei4 years ago
this is NOT true. you engine is still using gas.

SOME cars in SOME very specific scenarios "cut" the injector flow when a lot of very specific conditions are met.

for example my metro will do this but ONLY if I am over 2500rpm (NEVER) and decelerate with the car in gear.

since I never take it to 2500rpm (I try to max at 2000rpm and cruise at 1600-1700 rpm)

My injectors never turn off unless I turn them off.
JacobAziza (author)  denswei4 years ago
I do similarly to you (except I often coast in neutral, as some hypermilers claim it can wear out the throw out bearing to coast in gear)
but I left out these sort of details to avoid making it overly complex for people new to the idea.

nerys mrcllane4 years ago
My car has manual steering and manual brakes. There is "zero" difference in the car engine off or engine on except the gas pedal don't work anymore.

Thats it. Everything else is 100% identical engine on or off.
Joenavy85 nerys4 years ago
he does make a point though, too many people don't think about how shutting off the engine truly affects their vehicle.(though i doubt that anybody driving a Ferrari 360 Modena is going to shut off their engine to try to increase their mileage). i just put the trans in neutral and coast
yes but with older vehicles (and some newer ones) there is a spot in the ingnition where you can still have steering and brakes (if they aren't power brakes and if they are you have 1 shot with the brakes) so if you are in a wreck while coasting then you are the one at fault
nerys nclark5574 years ago
actually most properly maintained cars with power brakes have enough vac for 2-3 FULL presses of the brake pedal. and even when that runs out the brakes still work just fine they just take a bit of muscle. and all but the 90 pounds little ladies have plenty of leg muscles to work them just fine.

its one thing to have them "go out" on you its another when you know in advance whats about to happen (ie the brakes getting harder)

So unless your lacking on the maintenance you should be just fine.

power steering is nearly meaningless above 5mph.

oh and i forgot about a liitle thing called HANDBRAKES that you can use to stop even if your vehicle has ne engine (found that out when helping my dad tow my bro's  old wrecked car.(he lost it on a icy hill met a power line pole)
 

They need the engine running for power assist. Not to "work". This means they will be harder to use but anyone conscious of this particularly if they are going slow and using proper vehicle spacing should have no problems.
that's true, check out my instructable i made, and it appears the reason why. the instructable, i've read it, a quite time ago, and its quite good, as the aerodynamic features ;)
JacobAziza (author)  mrcllane5 years ago
Please read the entire instructable before commenting. I address both of these issues.
I know of people who died turning the ignition off while driving down hill. It happens every year. Think man, if you’re going to tell people to turn off their car while its moving, don’t you think it would be appropriate to give them a warning ON THE SAME PAGE they may die if they try it…….Step four. pffft
JacobAziza (author)  mrcllane5 years ago
About 45,000 people - over 100 per day - die in car crashes in the US. Auto accidents are the number one cause of death among all people under age 40. Driving is dangerous. Even with power brakes (and seat belts and air bags) driving is one of the most dangerous activities you can do. If you get in a car, you may die. If someone is following my advice, they are first off driving SLOWER than normal. Because force varies with the square of velocity, driving slower has an exponential (technically parabolic) effect on both stopping distances and the force of impact should an accident occur. If you practice hypermileing, it requires you to actually PAY ATTENTION when you are driving. If you are watching your gauges, looking at traffic lights 4 blocks down, judging following distances, and determining what gear to be in every moment, you aren't eating, talking on the phone, and changing the stereo. If you choose to coast engine off without changing to electric brakes (as I did for several months in my 2.5 ton truck) you need to be aware of your vehicle, and of stopping distances. However, I did not point this out because if you drive ANY vehicle, in ANY conditions, you need to be aware of your vehicle and your stopping distances. Since you are driving slower than other traffic, your following distances are already much larger than normal. Since you are trying to avoid wasting momentum, you are driving in such a way as to minimize your need for brakes in the first place. As to power steering, it is the most excessive and wasteful invention ever to have become a standard feature. Since changing my large commercial truck to manual steering the ONLY time I can even tell the difference is when I try to turn the wheel at a complete standstill (to get into tight parking spaces). Even moving at 1 mph makes it easy to turn the wheel. I say if you aren't strong enough to turn a wheel without help from a gas engine, you need to be out getting some exercise instead of driving a car.
I appreciate the effort and some of the stuff you’ve done. But safety first Bro. You’re not fooling anybody with your “exponential of parabolic velocity squared" BS. You should probably just walk.
funny-dog-pictures-driving-ten-and-two.jpg
JacobAziza (author)  mrcllane5 years ago
lol, "“exponential of parabolic velocity squared" BS"?
Yeah, uh - I didn't make it up. That's Newtonian physics. E=1/2m*v2
Driving slower is safer. You don't have to take my word for it.

"risk of involvement in a casualty crash, relative to the risk for a car traveling at 60 km/h, increased at an exponential rate for free traveling speeds above 60 km/h"
http://casr.adelaide.edu.au/speed/exec.html

“First, the probability of a crash is approximately proportional to the square of the travel speed. Second, in a crash, injury risk is approximately proportional to the impact forces on a person, which in turn are proportional to the square of the impact speed. These two effects can be summarized in a general rule of thumb: When travel speed increases by 1%, the injury crash rate increases by about 2%, the serious injury crash rate increases by about 3%, and the fatal crash rate increases by about 4% “
http://www.tsc.berkeley.edu/newsletter/winter2008/speed.html

Since almost no one drives at the speed limit or below, and speeding is the single largest risk factor in fatal crashes, clearly people do not consider safety to be their first priority.
If safety outweighed all other concerns, perhaps we should all drive tanks to where ever we are going.
Or, better yet, instead of wasting fuel in the supposed name of safety, just ride a bike.
JacobAziza (author)  JacobAziza5 years ago
Maybe part of your comment is because you are unaware of this point: the brakes and steering still work without the engine. They are just harder. You have to push the pedal harder and turn the wheel (slightly) harder, but the systems are still fully functional.
Agreed. It's easy to coast with my Mazda 323. It's harder in my wifes Tahoe 4x4. But it still CAN be done safely. I do it nearly every day. It just takes a little extra attention and effort.
He probably read all the way to step 4, then his brain turned off, and he skipped the rest
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JohnMichael4 years ago
While I am in favor of improved mileage, some of the modifications in this instructable are unsafe and illegal in most places.
Care to back that up with some references? 

Coasting with the car in neutral or clutch engaged has been illegal in my state since 1971 (and is illegal in many others) -http://www.leg.state.vt.us/statutes/fullsection.cfm?Title=23&Chapter=013&Section=01121

So when I am coasting in drive with my high stall torque converter, and the rpms sit at 1200rpms with my foot off the gas, I guess you could say that's illegal, since it's not technically grabbing a gear.

Not at all - if it's in drive you are in compliance. It's coasting in Neutral and/or shifting into Neutral (or for a manual neutral/depressing the clutch) with a vehicle in motion that's at odds with the law.

Now prius drivers can finally get back at Prius Repellers (big trucks) because they can drive one and enjoy the same MPG.

Rportal4 years ago
Driving slowly is illegal. It is called impeading traffic and you can be cited. Just so you know.
JacobAziza (author)  Rportal4 years ago

Driving slowly is not illegal in a single state in the US. The posted speed limit is, without exception, the UPPER LIMIT to how fast you are allowed to drive. It is NOT a mandate that you must drive that speed, it is NOT a recommendation, and it is most certainly NOT the lower limit.

If you deliberately came to a complete stop on the highway, then you are impeding traffic.
If you were, for example, driving 15mph in a 65 zone, you could be cited for a number of things.

However, even then you are not actually impeding traffic, because on a multi-lane highway, people can just change lanes, and on an undivided country road people can pass in the oncoming lane or at turn-outs.
On city streets or mountain roads where it is not safe to pass, it is also not safe to drive 65mph, so there is no problem.

No where do I suggest driving 15mph on the highway. Below around 45 or so (depending on the vehicle) you have to shift into a lower gear, and therefor your mileage drops off.

There are some (not all) states in which there is a minimum speed limit on some highways. When there is IT IS CLEARLY MARKED ON EVERY SPEED LIMIT SIGN.
In Michigan, for example, on some freeways with a 65mph upper limit there is also a 45mph lower limit. This means you can go 20mph slower than surrounding traffic (that's assuming no one is speeding)

Bottom line is, you NEVER have to base your speed on what people around you are doing. If every single person on the highway is speeding, except you, then every single person on the highway is breaking the law, and you aren't.

Don't just make up stuff that you wish was true. Almost all laws are posted on the internet, so you can find and cite the exact vehicle code you want to inform people of, instead of spreading false rumors and confusing people.
actually it is up to police descretion as to what is an impedment of traffic (which you can be charged for) and their working model is different state to state but if you stay within 20% of the limit(depending on conditions) you won't have any problems. Oh by the way you can be charged for driving at the speed limit as well if the conditions are bad. It is called negligent driving (for not adjusting to the change in conditions). Unfortunatly if you are charged with either offence it is difficult to fight in court as I know from personal experience ( I was lucky that I hold a raceing license as well therfore my knowledge and level of expertese was considered better than the police officer's involved )
laws are different in every state. what is illegal in one state might be perfectly legal in another.
Totally not true about posted minimum speed limits. Wisconsin has a 45MPH minimum speed limit on all Interstate Highways (I-94, I-43, etc) and it's not marked anywhere on any highway sign anywhere in the state. It is the same whether you're on a 65mph zone, or a 55mph zone, 45mph is the minimum. Of course, if the MAX limit is lower, then the minimum limit is lower as well, but there's no point in going 35 in a 45mph zone.
JacobAziza (author)  dragonriot2 years ago
I'll take your word for it and stand corrected.

I don't know of any modern vehicle which has max efficiency at a speed lower than 45 anyway, so there's no reason to go below that.
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