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Improving Mini Truck Fuel Economy

Discussion in 'Performance' started by Eljordano, Aug 14, 2008.

  1. GoFaster

    GoFaster Member

    few random thoughts and things to investigate ...

    Top end is indeed where the power is. Cams, combustion chambers, port shapes, etc.

    Intake and exhaust tuning are what let the cam timing do its job. Most production engines are not particularly sophisticated in this regard, particularly the exhaust system. Often they're designed with emissions, cost, and noise reduction as priorities 1, 2, and 3. Performance is far down the list.

    A good many production 4-valve heads have ports that are too BIG for the RPM range in which the engine operates. You need inertia to get "ram induction" and you need velocity to get inertia, and for that, the cross sectional area has to be in the correct range. Too big kills mid-range and doesn't help top-end. Same thing on both intake and exhaust sides. Too big might give impressive flow bench numbers but doesn't make power in the engine.

    Air/fuel ratio and ignition timing may be set more for emissions than anything else. A wide-band air/fuel ratio gauge and a vacuum gauge are handy tools for fiddling with this.

    A lot of engines run way too rich at full load, in the interest of keeping temperature and detonation under control ... but there are other ways of accomplishing this ...
  2. Mighty Milt

    Mighty Milt Active Member

    i spent a lot of time playing with cam profiles. lift, duration, ratio rockers and lobe centers. finding what translated well from static compression to running compression. how to make power where it's needed. i ran numbers on the strip that were unheard of from an engine my size. i played with rod ratios that seemed ridiulous until you realised how it unloaded the crank at 90* and let the motor run with less friction. every little bit counts.

    a 4 valve cylinder is a great design with the swirl and all that, it's more economical than a power house. there are things you can do to get "cheap power" out of it, yet, at the same time, you are going to lose the economy that has drawn us all to the mighty mini.

    i KNOW proven methods to make HP.. but if that was my only pusuit, i would be driving an old muscle car, like my old caddy with the 472cid and and 850 carb on top... it made tons of horse power, and would pass anything on the road... except a gas station (7mpg, honestly) or i would still be stealing money from the pockets of the teenagers in thier honda v-tecs with my VW



  3. GoFaster

    GoFaster Member

    I wouldn't think it feasible or worthwhile to muck with engine internals on something like this, unless the engine has to come apart anyway for some other reason ... You can spend thousands on custom pistons to do something to the combustion chamber shape, more than you would ever recover even IF you managed to get it more efficient than the factory setup, which is unlikely.

    But set-up-related stuff, like optimizing the ignition timing or the carb jetting, usually is worthwhile, as long as you don't go blowing something up in the process.
  4. Mighty Milt

    Mighty Milt Active Member

    efficiency and performance always leans towards any multiple spark discharge system where it helps ignite fuels tboughout the stroke of the combustion stroke. If these trucks were more common to where mfg knew about them and could be more helpful through an instal I would already have an MSD 6AL in mine for the efficiency and performance. That would be the best bang for the buck without a teardown, but when I blow this motor (and it's just a matter of time) i'll put some stank on it :D
    Last edited: Aug 28, 2008
  5. misterturbo

    misterturbo Member

    I'm an electrical engineer and I have to back GoFaster on everything he said..

    To make a long story short, fundamentally the mason jar scam deal is based on truth. It does split the water into oxygen and hydrogen. I know I can't be the only one who tried this when they were a kid, put battery leads in the water, collect the hydrogen gas and light it with a match and it makes a little pop noise..

    However, the amount generated is too small to do anything.. An engine, even our 660cc engines take in at least 5L of air per second.. That contraption generates maybe 2mL of hydrogen/second. Which is probably the same fraction hydrogen is naturally present in the air. So too dilute to do anything.

    Now if you did this on a larger scale.. Say have huge tanks that take up the bed of your minitruck and stick large metal plates in these tanks and collect the hydrogen, then maybe it might do a little more.. I'm guessing that probably isn't feasible :p

    And HHO isn't a different gas its just Oxygen and Hydrogen mixed together.. ie. you use it in welding, you have one tank putting out Oxygen, and the other tank putting out hydrogen, thats all.
  6. GoFaster

    GoFaster Member

  7. Mighty Milt

    Mighty Milt Active Member

    AHA!! the truth revealed... it works!! i found this on craigslist so we can all rest our weary heads, nothing is fake on craigslist and we all know that! :rolleyes:

  8. Timetripper

    Timetripper Moderator

    Glad to hear we got that settled :D
  9. rontopia

    rontopia New Member

    I have been reading and reading on this subject. I have no idea if it works or not. what I dont understand is how the laws of thermodynamics are broken if you use 6 to 10 amps to produce hho. while its not free energy.. speaking of the alternator.. it is already spining and using energy.. no one and i mean no one is saying that you can run your car totally on hho and have enough energy to produce enough hho to sustain the engine. that is what would violate the first law of thermodynamics.. not using 6 amps off an already spining alternator.

    we can post resumes if you want.. but i assure you this concept is not in violation of any Laws.
    Last edited: Sep 24, 2008
  10. GoFaster

    GoFaster Member

    Okay. Time to put some numbers to this.

    10 amps at 12 volts = 120 watts. Let's talk totally in watts from this point on.

    To get 120 watts of electrical power from an alternator whose drive mechanism and internals are about 60% efficient, you stole 200 watts from the crankshaft.

    Now you take that 120 watts of electrical power and put it into an electrolyzer. The simple ones people are proposing are not very efficient but let's be optimistic and call it 50%. So now you have 60 watts of "power" in the form of a stream of uncombined hydrogen and oxygen.

    Now you take that 60 watts and feed it into the engine air intake. The engine is probably 25% efficient under load, worse off load. So out of the 60 watts of chemical energy that you put into the engine, you get back 15 watts of mechanical power ... but you stole 200 watts of mechanical power in the first place to do all this, resulting in a net loss of 185 watts of mechanical power to accomplish NOTHING, a big loop of smoke and mirrors.

    The proponents (hand-wavers) always claim some miraculous improvement in combustion efficiency. Sorry, but the amount of hydrogen represented by that 60 watts of hydrogen and oxygen is minuscule compared to the fuel flow rate.

    Suppose you did this to a 40 hp engine (your mini truck running flat out on the motorway!). That is about 30 kW - 30,000 watts of mechanical power - but the fuel (chemical energy) input is about 120,000 watts in order to do this. Compared to 60 watts of chemical energy in the form of the hydrogen?

    The amount of hydrogen being used in this concept is about half a part in 1000 of the energy content of the fuel. Diddly squat zip zero zilch, in other words. And that's being optimistic about the efficiency of the electrolyzer. Meanwhile, you sucked 185 watts of mechanical power out - a little less than 1% of the engine's power output in this case.

    All of these HHO systems, every single one of them, is a scam and nothing but.
    Colin likes this.
  11. rontopia

    rontopia New Member

    as I said.. I dont know if HHO systems are a scam or not.. what I did say is that there are no laws being broken if it did. and I do think some of your figures are off.. be that as it may, I do not have a HHO system and am not planing on buying one. just so you know that are some out therethat produce almost 4L every 60 seconds at 10 or so amps. how much actual fuel do you think an engine actually burns in 60 seconds?

    the problem with this whole concept is not that it cant work because it violates the first law of thermodynamics. the problem is an ineffencent electrolyzer.

    even wtih all your figures above, of which some I dont agree wtih as far as taking 1% of the power for the engine.. those watts are there as long as the engine is turning.. is there more drag on the engine to produce 120 wats or 0 watts? coils still pass over magnets no matter what.. as long as the engine is turning.

    again.. weather HHo systems work or not I dont know. and Im not saying they do. i just dont agree with invoking the first law and saying see it cant work. because the first law is about perpecual motion of which this is clearly not.
  12. John Canfield

    John Canfield Member

    Alternator theory of operation

    The more current the alternator produces, the more HP it takes to turn it. Alternator output is regulated by increasing/decreasing current to the field winding. More current=more magnetism=more rotational resistance=more output. The old generators used permanent magnets.

    Fuel from water is old scam that has been around for years and years. Here's one brief story from 1996. Things like this surface every few years when somebody decides they can make money by recycling a 'revolutionary concept.' A common element of these hucksters is there is always an element of truth and believability in the pitch.

    However, it is your money, so spend it where you see fit :)
  13. rontopia

    rontopia New Member

    im still not defending HHO systems. Im not saying this works. never did.

    it takes more HP to get more watts.. understood. do you know how much HP it takes to pull off 10 amps. I work on things much much smaller. still its hard to believe that its much HP to produce 6 to 10 amps especially when you consitter how many amps it takes to run a modern car. the difference could not be that big. lights, AC, supersonic nutron smaching gonging sound systems, power windows, power doors, not to mention the electronics in the engine, onboard computer systems, GPS navi systems, cruse control,.. i could go on.. but a modern cars take how many amps and any given time? I doubt 6 or 10 amps would be missed if the total amps is within the spec of the alternator. that amount would be less in HP then your making it out to be. I think.
  14. John Canfield

    John Canfield Member

    746 watts equals one horsepower. At 13.5 volts and ten amps, that would be (13.5*10) = 135 watts or 0.18 HP (135/746.) Figure in 10-15% more for lost efficiencies and maybe you have used 1/4 HP to generate 10 amps. Not that much unless it is a very small engine ;-)

    But this is a wandering digression that will neither prove or disprove the subject in question.

    Those that strongly want to believe in something that is highly implausible and unlikely, will do so in spite of good data to the contrary.

    ron - please don't think I'm bashing you - not at all my friend. The remarks are directed to those that embrace the 'something from nothing' concept.
  15. rontopia

    rontopia New Member

    dont feel bashed on any little bit. i enjoy the discovery.
  16. GoFaster

    GoFaster Member

    4 litres of combined hydrogen and oxygen in 60 seconds? Two-thirds of that will be hydrogen = 2.66 litres of hydrogen in 60 seconds.

    Remember that we are talking about a gaseous fuel here ... it takes up a lot more space for the amount of energy it contains than a liquid fuel. I don't have the energy content of hydrogen on hand to dispute that. The amount of electricity that it would take to make that much hydrogen (at 100% efficiency which can never happen in real life) can be calculated, I just don't have my thermodynamics textbook handy.

    660cc 4 stroke engine spinning 6000 rpm (motorway speed) at say 80% volumetric efficiency will draw in 1584 litres of air per minute. Even if that electrolyzer made that much hydrogen (which I doubt), it's still nothing compared to the amount of intake air.
  17. Windmill

    Windmill Member

    A friend of mine at work put one a regular size truck. He is about the smartest person I know. He said he would not put one on for anyone else. I took that it might be more trouble than it is worth.
  18. JPM

    JPM New Member

    The only hope that this thing has is that somehow the hydrogen improves the combustion of the gasoline when mixed with it. When hydrogen is burned it returns back to water, and it can only release the energy that was put in it to begin with. If you used 120 watts to make it, the absolute most power you can get back out of it is 120 watts, and that assumes no losses. Other things have been used to improve combustion, such as multiple spark units, cool cans, carb spacers, etc. etc. and sometimes they work. I would seriously have my doubts with this system, though.
  19. BC_MMC

    BC_MMC Member

    I look at the propane conversion on my F-150 and how the tank would fit into the Mitsu... I see the 42.9/L vs 1.069/L for gas.
    20% loss of HP vs over 2X improvement in fuel cost.
    But I know propane burns more slowly than gas, that's why the engines last longer and wonder how it will affect such a high revving little unit. Tempted to try.
  20. Stuff99

    Stuff99 Active Member Staff Member

    ive had my fun with propane to. you will run into the same problem with these systems. mine is that no-one will work on the bloody thing because it is different...

    perfectly good propane powered 88 plymouth voyager ex military sitting because no one will work on it...

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