HHO is the gas resulting from electrolysis of water. Two H's and an O when seperated are very flamable. On top of being abundant it is cheap and cleaner burning than gasoline. Operating on purley HHO requires lots of modifications to a car but suplementing your gasoline with HHO requires little. There are a million sites out there on HHO car conversion kits. All of them are building plans for anywhere between 50 to 500 dollars. It seems odd that there is no instructable on it. So here, for free, is my attempt at making one. The text at the top is my first try and the text under the "-" line is my second try.
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Step 1: Tools and Materials

This page ended up changing through the process and can vary depending on how you choose to improve upon the design I used.

knife or strippers
soddering iron(not essential but saves time)
screw driver
voltage tester(depends)
*#7 bit
*1/4" tap
*may change depending on the electrode you use and how you connect it to the wire
Materials:(Keep in mind all the materials I used are "borrowed" from work or I had around the house so they won't be the most effective solutions. Be creative with what you use)

Plastic container (I used a grape juice bottle)
High temperature silicone sealant <-expensive; regular silicone sealant MAY work
Wire (I used some left over wire from the amp that went in my wife's car, 14awg)
Teflon tape
Plastic tubing (I had to siphon gas once to change the fuel pump and had this hose from it, not sure why I kept it but I'm glad I did)
salt (for an electrolyte in the water)
Stainless Steel Electrode(update: THIS WILL NOT WORK)
I put this one on bottom because it will have the biggest explination. I am told stainless isn't esential but will not corrode like other metals. I also read that coiled wire would be the best type(i.e. pipe, plate, wire).Platinum would be your number 1 choice but who can afford that? I used some pipe I found at work.

-I ended up using the graphite from 2 pencils as my electrodes
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RobC33 months ago

Been playing with this for about three months on 2007 Mitsubishi 380 (or Gallant in USA) Advertised combined fuel usage 12.1/100k's achieved 10.4/100 k's using HHO.(18amps) and Volo chip.

Issues faced ....using KOH as electrolite had issues with residue in throttle body , Air flow sensor has since failed ....pinging required change of plugs to colder firing plugs.

Current configuration with airflow meter disconnected and Volo disconnected delivers 10.6 k per 100 litres but lacks throttle responsivess.

Next move is to try adjustable EFIE's on PRE Oxy sensors.

eddieriver RobC33 months ago


I have had a hho generator on my 2.2 diesel van for about 12 months. I had the same problem with 2 failed air flow meters but I think I have solved the problem by putting an extra bottle between the bubbler and the air box. This catches any spills and splashes of the caustic and does,nt allow it to get any further.

For the record my van used to return 32 mpg. With gas I am getting 40 mpg.

Roarke6 months ago

this is a lot cheaper than most of the other instructibles and guides out there. I applaud you for an awesome writeup on how to test this for pennies to the dollar of the others! well done

jbaker228 months ago

There are better alternatives than to power the electrolysis off of the battery or the alternator. Look at this web site.

kurshiukas9 months ago

Ok, Now, I may be a bit off here, but according to my calculations .. burning H in your burning chamber would produce water (steam), now I do understand that its steam and it is usually blown off with 4th stage, BUT my question is would it really no harm feeding your engine with water?

Search for Stanley Meyer Water Fuel Cell, or Stan Meyer H20 Car

jea7241 year ago
SIR/MS: Sierra Club adherents and Biomass Supporters need to solicit our Senators and Congress to alter the new "Biomass Thermal Utilization Act (BTU ACT) to include large tax credits ($1.00 per gallon) for gas stations to sell Butanol Gas Blends (24%), Hydrogen Gas, Bio Deisel, CNG (Propane & Natural Gas) and installation of related kits for both Cars and Trucks. And tax credits for individuals whom get engine conversions to burn Bio Diesels and other alternate energy fuels. Likewise, and local state EPA supported coal to liquids or gas conversion plants should be Federally EPA approved automatically. And the largest Ethanol Plants (production over 20 million gallons per year) should be given Federal Funding to convert to Butanol Production (Cost is $15 Million each). This is needed to make the United States energy self sufficient and to give every American some relief from high Fuel & Energy costs and costs associated with transportation of goods via truck.
kurshiukas jea7249 months ago

sorry but, 3.652 USD per galon (this was the price I found for West coast today. Where I live (eastern EU) we pay 6.62 per gallon. Your transportation is cheap as hell :D

Fox321 year ago
I read the whole comment and i pray for the day when you could punch somone through the monitor. So much nonsesn from oooobabyooo and lucek, makes a man wanna do that. So bottom line, how efective is it?
lucek Fox321 year ago
Yeah Ignoring the snipe.

The end is this doesn't work.
dgt19731 year ago
used a similar rig back in 2010 on a '08 renault megane. DID NOT improve gas mileage and ended up needing a new cylinder head
I am looking to do this on 2 cars. 1 is a Nissan frontier 5 speed 4 cylinder. This is more the test subject before I do it to my 2500. I would like to know how or if you need to tune the car. Because it doesn't make sense that the car can adapt to the hydrogen. Any info will help thanks.
lucek1 year ago
@ jbaker22 then be careful. Hydrogen isn't just something you store in any pressure vessel. It will make you're fire extinguisher more brittle, Next you defiantly don't want to be using brown gas. The fact that it can spontaneously react with it's self kinda makes it dangerous. Finally just sticking thee pipe in the corroborator will work but if you are actually injecting a good amount of fuel in there is a chance for blow back.
jbaker221 year ago
Take a look at the link below. When your oxygen sensor reads too much oxogen, it will dump more fuel in the engine this site has enough information to improve you system and get better gas milage.
lucek jbaker221 year ago
That site was just like so many others. I guy dicking round with electrolysis and thinking he's saving money but not ever actually finding out that he's loosing badly. Again The physics of this say no.
jbaker22 lucek1 year ago
I am more interested in storing hydrogen generated with a power outlet and storing it in a fire extinguisher. Then it can be injected into the air intake.
thegsmiths5 years ago
New to site. So if this is an ignorant comment, please excuse. One of the points that most seem to miss is that the hydrogen is not used to replace gasoline, it is used to supplement it. By adding the hydrogen to the fuel system (via air intake, like NOS) you are then able to decrease the amount of gasoline needed (i.e. make the engine run leaner). The hydrogen makes up the difference so you don't lose power or cause engine knocks. I've used it on a 1990 Ranger with the same results as Jalakohops and have not had any problems with the truck's charging system. It may be because I am only producing a small amount of hydrogen, enough to decrease the amount of fuel needed thereby increasing my gas mileage. The only problem I have is with my electrodes. They do have to be replaced fairly often. It can be a pain, but the amount I save on gas is worth it.
I've covered this over and over and over in this thread. Hydrogen has no catalytic effect; that is to say that it does not improve the efficiency of combusting petrol in a piston engine. If there's a benefit to be obtained, it must come from the thermal energy yielded from combusting a certain volume of hydrogen produced by the electrolyser. Your truck's 80A charging system connected to an electrolyser will produce completely insignificant amounts of hydrogen. In actual fact, due to system losses (described many, many times in this thread), any electrolyser arrangement will REDUCE fuel economy. One thing is certain, you don't want to run the engine leaner than it is designed for. You risk serious and expensive engine damage (burned valves, holed piston crowns etc) if you do. If you're seeing an increase in fuel economy, you've made an error in measuring fuel consumption, have fixed simple problems like tyre inflation, are altering your driving habits, or something else easily explicable yet so far unaccounted for. I hope you're not simply lying. "HHO" systems will always consume more energy than they can return to the system.
Finally. We are getting to the point. Your statement here: One thing is certain, you don't want to run the engine leaner than it is designed for. You risk serious and expensive engine damage (burned valves, holed piston crowns etc) if you do. is the key. Because of the properties of the Hydrogen the HHO and Gasoline blend the engine can run much leaner without pinging. This is why people who use HHO on carb motors don't usually see a benefit but EFI cars do. The O2 sensors on the car measure only for stoichiometric. Gasoline is 14.7:1, H2 is 34:1. when mixed the final ration is somewhere much leaner than just gasoline. So an EFI car will adapt to the new fuel by pulling gasoline and allowing the car to run very lean. Under load the EFI system normally would add gasoline to get the ratio down as low as 12:1 to help cool the cylinders to increase the amount of air able to fit in. At high load EFI systems go into open Loop mode where they just work off of their programmed number rather than feedback from the sensors. So you still get that cooling effect. With an engine programmer you can pull some fuel out here if you are confident in your oil and cooling system. The flame speed of the blended fuel is much faster too, so you get more power by essentially adding "more timing" I think that these are the effects that are present when people talk of the catalytic effect of HHO. It is not a catalyst in a test tube, but is in an four stroke EFI motor. Even more so if you can reprogram the efi.
Sorry, this is complete nonsense. An electrolyser system running off a common automobile charging system will not provide anywhere near the amount of hydrogen necessary to make any difference whatsoever to the combustion temps.

On top of that, given the losses in converting mechanical energy to hydrogen (which I've covered so many times that I'm not going to cover them again), these systems will always, always, always produce a drop in fuel economy.

...and if you can't produce a catalytic effect from hydrogen 'in a test tube' you're never going to produce one in a 4-stroke engine.

You can fool yourself if you like- but don't try to fool anyone else, mkay?
You are really becoming a pain. Have you tried to use one or not
I don't have to jump off a cliff to prove I can't fly.
I was just explaining what some of the "Catalytic" effects are. HHO may not be a chemical catalyst that you would be able to find by doing analysis only on the BTUs generated. I totally agree that there is no free energy. But there are also a lot of inefficiencies in our gasoline engines that putting in a little more energy may rectify.
From Ye Olde Wikipedia: Catalysis is the process in which the rate of a chemical reaction is either increased or decreased by means of a chemical substance known as a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself.

Hydrogen has no catalytic effect. It does not improve the combustion of anything, petrol included.

Modern piston engines with fuel injection and computerised engine management systems manage to burn 99% of the fuel introduced into the engine. However, piston engines are only about 30% efficient in converting the energy in petrol into mechanical energy. This inefficiency is not due to failure to combust the fuel efficiently, it's due to friction and a requirement to limit the combustion temperatures, both to preserve the integrity of the metals the engine is made of and prevent the formation of nitrogen oxides (atmospheric air is about 73% nitrogen- extremely high combustion temps form NOx). Quite a lot of the heat produced by burning petrol in a piston engine is removed by the cooling system instead of being used to move pistons. Adding more fuel (and that's all hydrogen is in this application) or replacing some petrol with hydrogen does nothing at all to reduce the losses in a piston engine.

Last time: 'HHO' is a HHOAX. There's no way to generate hydrogen using an automobile charging system that will not reduce fuel economy nor will hydrogen reduce the losses in a piston engine. Any technique which removes mechanical energy from a drive system and converts it into other forms of energy will always reduce the efficiency of the drive system, due to the laws of thermodynamics and entropy. There's losses in every conversion.

If you want to improve the efficiency of a piston engine, you must find a way to make use of thermal energy which is wasted and/or exhaust pressure or reduce friction losses.
Only about 15 percent of the energy from the fuel you put in your tank gets used to move your car down the road or run useful accessories, such as air conditioning. The rest of the energy is lost to engine and driveline inefficiencies and idling. Therefore, the potential to improve fuel efficiency with advanced technologies is enormous.
Engine Losses - 62.4 percent
Idling Losses - 17.2 percent
Accessories - 2.2 percent
Driveline Losses - 5.6 percent
Aerodynamic Drag - 2.6 percent
Rolling Resistance - 4.2 percent
Overcoming Inertia; Braking Losses - 5.8 percent
But you are the scientist right? If your day job consists of facts and science Please resign before you kill someone or yourself!
Where, pray tell, have I identified myself as a scientist? I'll save you some effort looking about- I've said no such thing, because my line of work is immaterial to the fact that "HHO" toys don't work.

Every single thing you have painstakingly enumerated has nothing at all to do with the efficiency of an internal combustion engine, which "HHO" toys are supposed to improve- but don't.
"At high load EFI systems go into open Loop mode where they just work off of their programmed number rather than feedback from the sensors"

I thought that was full throttle under load, not just high load.
I've read some fairly authoritative stuff on using straight hydrogen in an ICE, and also a combination of hydrogen and fossil fuels.

Hydrogen will still combust sufficiently to run an engine, at ratios higher than stoichiometric. Far lhigher, which is good, because apparently NOx is much higher at that ratio.
RalphNader2 years ago
This entire topic is a testimony to the lack of science education in the schools these days, and the lack of common sense in the public at large.

First, the chemistry and physics. This silly rig will not increase mileage. It will produce, at best, a tiny amount of hydrogen. And in order to produce that hydrogen it places a tremendous load on the vehicle's electrical system. There is no free lunch in physics: that energy is being drawn from the output of the vehicle's engine, reducing the amount available to propel said vehicle down the road.

Then there's the mechanical matters. People are playing around with sulfuric acid, generating extremely explosive oxygen and hydrogen mixes, and casually dismissing the generation of chlorine gas. This isn't just bad science, this is seriously dangerous stupidity.

And the credulity of the supporters of this "HHO nonsense" is amazing. If it worked, the automotive industry would be all over it. They are under huge public and regulatory pressure to increase the MPG ratings of their vehicles. If "HHO" worked they would have seized it and shoved it into every car rolling off the assembly line. Instead, they are spending billions on actual engineering work. Billions they could be pocketing as profit if "HHO" worked.
The argument that he must spend electricity and therefore is not a cost-effective solution is not relevant. Your opinion that made the car alternator driven continuously by the engine?

L'argument selon lequel il faut dépenser de l'électricité et donc que ce n'est pas une solution économique n'est pas pertinent. A votre avis que fait l'alternateur de la voiture entraînée en permanence par le moteur?
For note what he wasn't talking about wasn't opinion or an argument. They were simple physics. The equations are simple. The total energy of a system is conserved. Any action will not be 100% efficient.
otiman2 years ago
HHO is a mean to an end... IE using electricity to (help) power an ICE! that is all.

IF you have a cheap or GREEN source of electrons, you can add some batteries and improve your milleage (end of story).
crestind2 years ago
The cognitive dissonance is strong in these comments. "I refuse to believe HHO can improve my mpg!" Too bad. More mpgs for me!
adamwd842 years ago
A note on the electrolyte, instead of using sodium chloride it is recommended to use lye (caustic soda) so you aren't emitting chlorine gas with your exhaust.

I've noticed a couple people insisting in the comments that supplementing fuel with oxyhydrogen will not work. There have been official studies that prove an increase in fuel efficiency. Several are listed here

Eagle Research also has a book on how to design and build your own generator
or you can get a fully assembled device along with all the instructions for installing it and optimizing it
lucek adamwd842 years ago
And there have been more actual studies that find that the laws of physics actually work.

Eagle-Research, Inc. isn't a reliable source. Right next to the "research" on HHO there is "research" onperpetual motion machines.
lloydrmc2 years ago
Wow. No comments from Lucek or oooobabyoooo for a while.
lloydrmc2 years ago
Incessant repetition is the province of the rhetorically weak-minded.
lucek lloydrmc2 years ago
Sir you've done nothing but sidestep actual points. You've got no let to stand on.
lloydrmc lucek2 years ago
No, I'm not the one sidestepping actual points, just because I'll not bow down before the arguments of a couple of people. One has taken to posting exactly the same, letter-identical non-response to each and every point I make.

Just who is the spammer here? Just who is "sidestepping actual points"?
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