How to get better fuel economy w/your diesel



  • jim314jim314 Member Posts: 491
    The water fuel claims are bogus, and the sites that promote it are a scam. Water contains no net fuel value. It requires more energy to electrolyze water to split it into hydrogen and oxygen than you could gain in hp when the hydrogen is fed into the hydrocarbon fuel stream.
  • ladykathleenladykathleen Member Posts: 2
    Hello Jim314,

    You have of course converted a diesel or other vehicle to using water??????????????? The conversion "kits" seem plasible. They are inexpensive so who out there has actually done the conversion and what are the results????????????????
  • diehardforddiehardford Member Posts: 50
    In my opinium injecting water into a diesel is a big mistake and the repairs could be very expensive. A good web site to go to would be, then to their research and development site then hydrogen fuel info. These guys have been working on a hydrogen fuel conversion kit and hydrogen generator for quite some time. per them diesel will not run on hydrogen.
  • jim314jim314 Member Posts: 491
    One has to be properly skeptical of all engine add-ons which are claimed to increase fuel efficiency. In the specific case of the electrolysis units which produce a miniscule amount of hydrogen and oxygen gas, there is no generally recognized scientific or engineering theory whereby they could do what they are claimed to do.

    If they really did work as claimed, then they would be available from the vehicle/engine manufacturers, at least as an option. The purveyors of these devices are not bound by an ethics policy to conduct accurate and unbiased studies showing that they really do work. They cite unreliable anecdotal accounts as evidence that these devices work.
  • jim314jim314 Member Posts: 491
    The hydrogen enrichment devices currently available produce a miniuscule flow of molecular hydrogen and molecular oxygen, but the purveyors are claiming big benefits without any research to back it up. They cite research done at the US gov't Idaho National Laboratory, but that research does not support the claims of any benefit from extremely low levels of hydrogen enrichment.

    For example, one company is currently selling their brand of hydrogen enrichment device for installation on large diesel trucks (over-the-road tractor-trailers, I assume) and diesel school buses. The unit is an electrolysis unit which sells for $7800 plus installation charge of $200, so $8000 installed! The company reports that the unit consumes two liters (2 L) of water per 10,000 to 12,000 miles! 2L of water weighs 2000 g, water is 11.1% hydrogen so this 2L would yield 222 g of molecular hydrogen (H2) over that 10,000 miles!

    What is the mpg of a large diesel tractor-trailer? 8 mpg? 4 mpg?

    Let's say 6 mpg. At that rate over 10,000 mi it consumes 10,000mi / 6 mpg = 1667 gal of diesel fuel. 1667 galUS is 6309 L times the density of diesel fuel, 850 g/L = 5,360,000 g of diesel fuel over 10,000 miles.

    So the added molecular hydrogen as a percent by weight of the diesel fuel = 100% x 222 g / 5,360,000 g = 0.0041 %.

    Such a low level of hydrogen enrichment has not been shown in properly controlled trials to have any beneficial effect. This is 1/100th to 1/1000th of the minimum amount of hydrogen that has been studied in hydrogen enrichment experiments. See

    I think it is money not well spent for some struggling shipping company or independent operator to be paying this much money for something which has not been tested in well controlled trials. The FTC should investigate these claims.
  • cotcot Member Posts: 1
    What gears did you get the 07 GMC??? My 2002 7.3L Lariat was also stolen two weeks ago.
  • joe183joe183 Member Posts: 1
    I have an '06 with 3.73's and the 6 speed manual. I was disappointed as well the first time I drove it finding such high RPM at highway speed. I had traded an '02. It had 3.55's and the NV 5600 tranny. The newer ones have the Getrag tranny. The difference is not only the lower geared rears but also the fact that the overdrive ratio in the NV 5600 was .73 and it is .79 in the Getrag. I felt I had no choice but to go to the Gear Vendors overdrive unit. I installed it in my garage with a buddy in about 5 hours. You will have to get the rear driveline shortened and a different yolk welded onto it.

    I still had the stock tires and at 70 mph I was turning 1800 RPM. I drove from Billings,Mt to Bismarck, ND at about 67mph (1700 RPM) and got 20.3 mpg. I definitely improved my mileage. Since then I have installed a Lorenz 2 inch levelling kit in front and went with 35 inch tires. Also a Ranchhand bumper. Now at 70 I am at 1600 RPM and my mileage is about 15 mpg. I have installed lockouts and only noticed marginal improvement. Between the lift and the heavy non-aerodynamic bumper and, most of all, the larger tires, I think my mileage has taken the hit. Bottom line is that you will improve your mileage with the Gear Vendors unit but stay with the stock tires or only a wee bit larger. The other option would be for me to run in 5th gear overdrive at about 60 (1700 RPM). In that case the torque multiplication is signifigantly larger than in 6th overdrive and my mileage would likely improve. I just don't have the patience.

    Lastly, I drove over the road for 10 years. Cats, Cummins, Detroits. You will notice that the peak torque on the Dodge Cummins is generally around 1600 RPM. That is where you will get the best mileage. The idea would be to run a slower speed at that RPM which is entirely possible with the overdrive unit. I wouldn't agree that one needs to "keep the revs up" to run one of these engines.
  • whoopbang123whoopbang123 Member Posts: 1
    I also have a 2008 Ford F250 XLT Crew Cab 4X4 short bed, 6.4 Diesel with a 3.73 rear end. My first day of driving at approx. 65 mph, the vehicle averaged 9.3 miles to the gallon on the highway. One week later I'm averaging 13.3 on the highway at 65 mph. With a baseline of 65 mph on the highway, I've started researching various methods on how to increase my fuel mileage. My goal would be to reach or exceed 16-18 miles a gallon at 65 mph on the highway. Don't really know if this is due able but I'm trying. At this point Hypertech makes a programming device which will improve fuel economy by altering or tuning the motor for performance. So I purchased it. Additionally, I'm in the process of obtaining a new K & N Air filter that I believe will replace the stock air intake system on the twin turbo's. I guess my real struggle lies in the exhaust system or cat back. One person suggested I cut off the Particulated filter and run a straight pipe like a cat back. He said it will throw an error message but this can easily be reset. When I asked my muffler shop about this they encouraged me to keep the Particulated filter and just do a cat back. Any ideas on where to go from here? Or am I taking the wrong approach to this entire quest? [email protected]
  • grbjgrbj Member Posts: 1
    Hi Fuel Economy for Diesels Folks
    I came to your site looking for better fuel economy ideas, and see a lot of you ragging on the hydroxy approach. I personally have two 30 liters/hr units installed because I do lot of heavy pulling w my '97 7.3 liter F 350. The truck is not even broken in yet [only 38 k miles] but the cost of the fuel is threatening my retirement plans.
    Since I am buying to equip a farm and develop property a hundred miles north, I do nothing consistently enough to develop a good set of comparative stats. But I do know many of you are not very well informed about what hydroxy purports to do. Let me make some points.
    I have read that it would take 3000 lit/hr to idle a small engine, so adding only two percent to the air intake is not a significant power source.
    1. Nevertheless, the addition of the hydroxy gas significantly increases octane, i.e., the number of the 8-carbon (chain) molecules in the fuel mixture. [FYI, methane is a molecule with everything attached to a single carbon atom, propane has three, butane four, and they all boil off the crude at different temperatures in the cracking/refining process. Any fuel is a blend of different percents of the different chains and related components, all of the pieces that make organic chemistry both highly complex and difficult. Thus adding pure (and purity is critical) acetone or zxylene to fuel in small quantities can really increase performance, or do nothing at all, depending on the mix in the initial blend.] Higher octane levels increase fuel combustibility.
    2. Regarding the energy used in its production, the hydroxy gas is electrolyzed with the extra alternator capacity for winch use, cold weather, et cetera, but otherwise dumped via grounding circuitry to prevent over charging and damaging system batteries at other times.
    3. Running the hydroxy gas through small water tanks has a double purpose. The water tank prevents random back charge explosions of the volatile gas in the generators themselves, but the various ions created in the [electrolysis] process also charge the water, letting its various vapors both aid in combustion and damp slow or late combustion, a task engine designers typically accomplish by feeding the engine an unnecessarily rich fuel mixture. Carbon fuels have become too expensive to be used partially as fire extinguishers, however much such mixtures simplify design for engineers and auto mechanics. Rich mixtures are necessary for starting and cold weather operation, but not leaning the mixture as much as possible the rest of the time is a waste of resources, especially in light Congressional calls for better CAFE [car average fleet economy] standards.
    4. But the ecu [the on board computer system controlling combustion, braking, et cetera] can void all the above by detecting the leaner combustion [increased oxygen, or manifold pressure, in the exhaust system] and upping its fuel mixture imperatives to the carburetion/fuel injection system. And federal law makes disabling on board diagnostic components illegal. Whether capturing sensor signals and attenuating them back to the levels the system expects, to sustain better system performance, is a grey area. Apparently the trucking industry has explicit permission from the federal DOT for such experimental modifications. But for obvious reasons, the ordinary citizen in his domestic vehicle does not. Nevertheless, the driver who does not monitor his systems and limit its unnecessary negative responses is just spinning his own wheels.
    5. So why have auto manufactures not installed such systems in new vehicles, or at least made them available as options?
    1) they are complicated.
    2) they require more maintenance than advertised.
    3) they expose sloppy users to significant dangers, i.e. explosions, chemical burns from catalysts, economic losses from faulty information about installation and use, et cetera.
  • dawsrtdawsrt Member Posts: 1
    Hi everybody, I'm new to this site so please bare with me. I recently purchased a new motor home on a Kodiak chassis with 6.6 duramax. I drove it home from Indiana to my home in Vermont averaging 8.3 mpg. Keep in mind that there is only 1,700 miles on it. I have asked several people how to get the best mpg and some tell me to drive on the conservative side and some tell me to drive it like I stole it. The idea behind that premiss i was told is to keep the engine as hot as possible so as to burn all fuel incoming to the engine thus increasing fuel economy. I will say that I had to do alot of mountain driving a few weeks ago, pushing it real hard and got 12.5 mpg on that outing. Is there anything to this theory or not I just don't know. Any advise would be appreciated.
  • KCRamKCRam Member Posts: 3,516
    Your RV is certainly heavy enough to give the Dmax the work it wants. But since it's new and low on miles, you do want to keep the rpm (and heat) up until it's broken in and the rings have seated. This is particularly important since I imagine you won't be driving the RV every day.

    Best practices during break-in:
    - downshift on hills, both up and sown, this keeps the rpm up.
    - shift the trans manually when possible, keeping the upshifts as late as possible (whether you have a stick or automatic)
    - if you're on an open stretch of highway, downshift and stomp on the go pedal... this keeps your speed safe, but gives the engine more work to do

    Once you've broken in, then you can drive conservatively.

    kcram - Pickups Host
  • steelkensteelken Member Posts: 3
    I have a 2007 F250 6.0 ltre 2x4 crew cab at present I average 6.2 ltres per 100 klms .when my wife drives she gets 5.9 ltres /100 klms excellent to us. only added k&n filter system
  • steelkensteelken Member Posts: 3
    I have a 2007 crew 4x2 6.o .I use 6.1 litres for 100 klms ( 30+ to a canadian gallon) I installed a K&N filter system and improved from 26 mpg
  • ingarageingarage Member Posts: 4
    I don't know if it's possible to do what I want to do. I may be taking a job that requires a lot of freeway time and the company will buy my fuel but they want us to drive vehicles that get at least 24 mpg, typically cars. I want to use a 1 ton dually because I need one to pull a 23,000# gooseneck 4 or 5 weekends a year (on my time). My business driving will be at 65-70 mph, generally level freeway near sea level in California. I would buy a used truck, looking for the right gear ratio and tranny, and would make whatever mods necessary to the plumbing and programming, plus tonneau cover. Probably 2WD to save weight and height. 1st choice is Dodge mega cab short bed, then 6.0 or 7.3 Ford crew cab short bed. Has anybody achieved this average freeway economy? 5.9 Cummins likely more economical than the new engine? Is 3.54 a good ratio for this speed? Advice on engine mods? Do I have to have a stick? Do dual wheels kill me? I don't know if I'd want to tow that much with singles, even a few times a year.

    I realize low numeric rear ends mean tougher towing with that big load. This would be at 55-60, so is there an automatic that will downshift to the right gear, or should I be looking at a manual? I'd go with an underdrive or overdrive if that give the most versatility. Again, I am willing to have an imperfect towing rig to get the high mpg unloaded.
  • jim314jim314 Member Posts: 491
    You're dreaming that with mods and option choices you can get 24 mpg with a truck that can tow a 23,000 lb gooseneck.
  • gagricegagrice Member Posts: 31,450
    Just take the money for 24 MPG equivalent and pay the difference. I think 20 MPG is more realistic for a 1 Ton Dually.
  • longtallsamlongtallsam Member Posts: 1
    It may be possible with an '06 or older Dodge Cummins. I had an '03 2500 2WD, and after getting broke in good, it was consistently getting 26-27 highway, running 75 mph. I then had an '06 2500 2 WD, and it got 23-24. Both of those had the auto transmission. I don't think the Fords get that kind of mileage.

    I then traded for an '08, because I wanted 4 WD, and that was a big mistake! I had to replace the catastrophic converter and particulate filter at 17,000 miles, and have never gotten better than mpg.
  • thelawnguythelawnguy Member Posts: 3
    I have a 2000 Chevy silverado 1500. I haul 2 commercial mowers on a 6.5'x12' single axle trailer. The truck pulls okay, it has 173k miles on it though. I am going to buy a new truck, and thinking about a 6.8L v10 F250 (gas engine) I'm skeptical about the fuel economy though. I have no clue how much more I will spend in gas. Will a heavy duty truck with more pull power have close to the same gas mileage as a lighter duty truck pulling a trailer with mowers?
  • txfire1txfire1 Member Posts: 3
    You can have a straight pipe on diesel trucks and pass state inspection. Diesels have dif than gas trucks. Yes it is that common. I dont know very many guys that keep the factory exhaust. And as for riding your bike a 2 lane country road.......what else do you expect???? I hate it when people do that. Thats why they have SIDE WALKS.
  • tvoltvol Member Posts: 1
    I was pulling my travel trailor when the turbo hose that routes back out towards the radiator had the clamp at the turbo fail. Since then I have lost about two miles per gallon according to the MPG display. Any suggestions?
  • watkinstwatkinst Member Posts: 119
    A few things about diesel. Yes the military is a major user and can impact availability ie price. The second largest application of diesel product is Jet Fuel - its nearly the same stuff. Heating oil also factors in around this level also.

    3rd largest consumer is heavy trucks and equipment

    The small fry boaters - passenger cars and light duty trucks aren't even a blip on the consumption scale.
  • watkinstwatkinst Member Posts: 119
    The off road diesel ie - red dye diesel is cheaper and lower quality which the heavy equipment it tractors and such are Ok with - but the newer diesels will have major fuel system failure as the sulfur cakes up the fuel system. This is why the on road diesel was switched to lower sulfur content to allow the new diesel engine tech and performance which has led to new vehicle models turning out gas car like performance with diesel engines and 30+ percent better milege.

    Running the off road diesel in more current on road engines is a very risky bet not to mention the fines if your caught are not cheap. Nor is a fuel system failure.

    The crap that old farm tractors will run on will stop up your normal diesel pick up pretty quick not to mention foul up your fuel filters. Diesel engines have one major weakness - they need clean fuel and the high tech one's need sparkling clean fuel or your looking at some major issues.
  • nme1nme1 Member Posts: 1
    We have a 2008 F250 Diesel with 51,000 miles and are still get terrible fuel mileage. It averages between 11 -12 and thats with a chip. We are thinking about changing rear ends (now has 3.73) . Has anyone ever done this and improved their fuel mileage?
  • rodougrodoug Member Posts: 5
    My understanding is that changing to a 4.10 rear end will further decrease your mileage. I was under the impression that the 2008 change in the engine and exhaust system to lessen the emissions was the problem.
  • bsteve1bsteve1 Member Posts: 1
    can't remember my gear ratio but it's higher, highway gears, I wish I had 3:73's. I mostly city drive with a moderate load on and I'm only getting 10 mpg. Empty with a family traveling I think I was getting about 12mpg
  • rsnedegarrsnedegar Member Posts: 2
    Purchased an F-250 super duty and have been averaging 9-12 MPG around town driving the posted speed limit. Will tow my 4,000 Lb boat this weekend for the first time and I'm concerned about the millage I will get. I understand installing a chip only has minor benefits to the fuel economy but I'm willing to try it. Any recommendations on what brand/chip/programer to go with to increase efficiency?

    Thanks for any advice
  • rsnedegarrsnedegar Member Posts: 2
    How did things work out with your planned upgrades?
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