How to properly install and tune a Hydrogen On Demand (HOD) system in a gasoline powered vehicle

Difficulty: Challenging

Instructions

Things You'll Need:

Electrolyzer-capable of 1-3 LPM @ 13.8v/ no greater than 35A
Bubbler container with in/out ports
flash back arrestor
fuel heat exchanger
EFIE device
MAP adjuster
Starter solenoid/relay
Toggle switch
Resistor kit, or several potentiometers 10k, 20k, 50k
Fuel line
connecting hoses for HHO system
10 gauge wire, red & black
Crimp-on lugs
Brass hose barbs
Hose Clamps
Scan Tool
Optional EGT gauge

Step 1

My homebrew electrolyzer- 1.8 LPM @18 amps

THE ELECTROLYZER- This is the core of your HOD system. Just like a radio is of little use without a good antenna, an HOD system is of little use with a poor electrolyzer. Try as you might to increase engine efficiency, an inefficient electrolyzer will soak up most of any gains you might achieve by putting out too little LPM of hydroxy for too much current from your battery/alternator.

With most vehicles it's important to stay under 40 amps of current draw to avoid electrical strain on the alternator/battery. At 40 amps you should be seeing at least 3 LPM from your electrolyzer with minimal heat. (under boiling temperature)

It's not always best to run the maximum hydroxy though. For 4 cylinder cars usually 1-1.5 LPM is plenty to get the job done. 6 or 8 cylinders get a little better kick from 2-4 LPM. The people out there on YouTube that are trying to build these "mega-cells" for HOD are totally missing the point. Are you trying to run the car on water or simply enhance combustion? Pick one. Too much HHO and you'll actually force the engine to work harder, fighting the upward motion of the piston, screwing up engine timing, and more. A little water gas goes a long way, but at least 1LPM is essential to begin to do anything.

Do lots (and I mean lots) of research on electrolyzers. Dry Cells the best LPM for the current draw, with the lowest heat. (although many people lie about these specs so use caution)
Look for lasting build quality and know what's inside anything you purchase. Do not accept anything less than 316L grade stainless steel for electrodes. Even 304 WILL break down over time, so make sure it's 316L or better. Try to find positive postings or results with a specific electrolyzer before you purchase it. \

With the internet market for an electrolyzer being shady and full of made-up nonsense, scams, and rip-offs it might be better to build your own. Just be sure to demand the same rigorous specs and quality from your work and do plenty of bench testing long before the vehicle install to ensure you have a safe and functional product that will last in the harsh environment under the hood.

Mount your electrolyzer in a suitable place away from moving parts and away from the engine heat as much as possible. Wire the positive lead through a solenoid (relay) and an ammeter. Negative goes straight to a good vehicle ground. Use a ignition active source to fire the solenoid and a toggle switch to kill that circuit in the event you dont w
Step 2

My homebrew rubbermaid bubbler, the pop lid serves as a pressure release valve

THE BUBBLER- A simple container of water with an inlet port draws the HHO through a tube and to the bottom of the water. From there it bubbles up through and is released through the outlet port, to your engine. This simple device serves as your guardian and protector for two reasons: 1. In the event of a flashback (usually triggered by a back fire) the water in the bubbler serves as an isolator to prevent the hydroxy gas from exploding all the way back to the electrolyzer and possibly destroying it. 2. It serves as a "scrubber" to effectively remove traces of your electrolyte from the hydroxy before it gets sucked into the engine. Sodium Hydroxide, Potassium Hydroxide, and baking soda all can cause damage to your engine if they make it directly into your intake manifold. It is extremely important to take precautions to prevent any electrolyte from making it to the engine.

Hook a hose from your electrolyzer output to the bubbler inlet, making sure it's the side with the tube under water. Hook a hose from outlet of the bubbler to a hydroxy injection port on your AIR INTAKE. Do NOT use the vacuum manifold for HOD systems under any circumstances. The vacuum manifold supplies max suction when we least need it and increases your chances of getting electrolyte into crucial engine parts.

NOTE:You may choose to put an additional flashback arrestor between the bubbler and the intake to further prevent an explosion even at the bubbler. This is what I have done after my bubbler was destroyed in a flashback.
Step 3

The fuel heat exchanger, installed on the radiator hose

THE FUEL HEAT EXCHANGER- This device, when used by itself will not produce fabulous increases in fuel economy, but when included with HOD it makes a notable improvement. It's just a simple assembly of metal pipe fittings with in/out ports. (I use the water4gas design and it works well) You attach the device to your radiator hose and re-route your fuel to it before the injection manifold. The fuel is then pre-heated for better vaporization when it gets to the injectors. The device is wrapped in aluminum foil to act as a thermal blanket and heat the unit/fuel throughly. To install just follow your gas line from the rear of the vehicle to your injection manifold. If you have a fuel pressure release valve on your injector rail use it first to release the gasoline pressure, then cut into the line and re-route using high pressure fuel line hose and brass hose barbs to your heater, then back to the injection manifold. Lastly, wrap the heater in foil and use tie-wraps to lock into place. Use hose clamps for the connections and be sure to check regularly for leaks to prevent any danger of fire.
Step 4

EFIE mounted at firewall

THE EFIE DEVICE- If you were to install the above but do nothing else, chances are for most cars your MPG would either stay the same or get worse. Why? because the hydroxy is creating a different combustion environment inside your engine. It's an environment your car's ECU and sensors are no longer addressing properly, because you have deviated from factory specs. You are now burning your fuel better and reducing hydrocarbon deposits in the exhaust. Your o2 sensors are not seeing anywhere near the normal amount of hydrocarbons (pollution) in the exhaust and in fact see more clean oxygen. Why is this a problem? Because less hydrocarbons and more oxygen usually mean your engine is running a lean mixture that is in danger of overheating the valves. (not the case with HOD which is keeping everything cool) The ECU can't allow potential damage to the engine, so it will add more fuel to see the level of hydrocarbons and less oxygen it's used to seeing. Any gains created by your HOD system are then swept away by the ECU increasing the fuel consumption.

Add the EFIE. The EFIE (Electronic Fuel Injection Enhancer)effectively tells the ECU through the O2 sensors that the oxygen content of the exhaust is normal, thus restoring the balance and allowing the HOD system to work in a positive direction with fuel economy gains. The EFIE "tells" the ECU everything is ok in the exhaust by adding a slight increase in the O2 sensors' voltage to offset the amount of oxygen your HOD system is adding.

The EFIE can also be used to lean the fuel mixture very slightly by telling the ECU the exhaust is slightly rich in hydrocarbons, but this cannot be done easily without tuning other sensors on the car to coincide. Attempts to do so without tweaking other sensors usually results in a check engine light or trouble code. See the various sensor mods below for more on this.

For most cars pre 2000, usually only the O2 sensors previous to your catalytic convertor (upstream) are the ones that will need to interface to an EFIE device. For cars post 2000 both the "upstream" and the "downstream" sensors will need to be addressed.

Install your EFIE device in accordance with it's manufacturer instructions. I found a good general adjustment point to start from is about 150mv added to the O2 signal. Do not add a whole lot until you address the other sensors on the vehicle, or you will run into check engine lights, rough engine, bucking, stalling, sputtering, pinging etc.
Step 5

The modded CTS sensor

CTS SENSOR MOD- The goal is to add about 10 degrees to your coolant temperature sensor reading. It's important to note that the actual coolant temperature will remain the same as it normally would be. We are merely fooling the ECU into "seeing" it 10 degress hotter. Why? A seemingly warmer engine promotes less fuel usage and allows leaner mixtures for the ECU, which it can now run because the HOD is protecting the engine by keeping it cool, as well as burning smaller amounts of gasoline more efficiently.

Find the CTS sensor and the wiring harness leading to it. With a razor remove a small amount of insulation on both leads of the sensor, then solder a resistor across the leads in parallel to achieve the desired 10 degree offset. I used a 3.9k ohm resistor but you might need as high as a 5k to get it right. Try not to go much above a 10 degree offset or you might run into starting issues because the ECU will think the engine is already warm when cold starting. Better yet, make the resistor mod switchable with a toggle and you can switch it in AFTER the engine is warmed up. This will avoid cold start issues entirely.
How do you know you've raised the temp 10 degrees? The crude way is to look at your temp gauge on the dash. The best way is to use a scan tool such as a scangaugeII to know exactly what the ECU sees.
Step 6

The leads on the IAT sensor go to a potentiometer in the cabin for control on the fly

IAT (Intake Air Temperature) SENSOR MOD- Once again we need to fool the ECU into thinking it's sensors are in agreement about the current conditions. If you have the CTS tweaked but not the IAT the ECU is not likely to comply with leaning out of the fuel trim.

The IAT has a big effect on engine timing. Raising the temp retards the timing and lowering it advances it. With a hydroxy system we are actually looking to retard the timing because of the flame propagation speed increase within the combustion chamber using the system. It's important to add that the next modification of the MAP or MAF sensor will advance the timing, so you're looking to adjust the IAT temp a little over the mark for timing so that our final MAP/MAF adjustment brings the timing in perfectly. 80-100 degrees above ambient sounds dramatic, but is typically a good starting point. You will need to experiment with resistor values to find the right one for your vehicle. I used a 20k pot with a 500 ohm resistor in series to keep it from shorting out the sensor. This mod is also switched with a toggle after the engine warms up. This mod is sweet in that it allows me to "dial" in the correct value for the IAT, and find the optimal setting for economy. I adjust IAT for max power.

NOTE: A scan tool is a MUST for this mod. You need to know the IAT that the ECU sees to make the mod.
Step 7

RE-ADJUST THE EFIE- ok, the CTS and IAT sensors are in agreement for a slightly leaner mixture, so time to adjust the O2 sensors as well with the EFIE. Now that you have effectively "lowered your lean limits" to the ECU, we can add more voltage offset to the EFIE and get away with it. No check engine light or trouble codes to worry about, just don't get carried away. Go a little bit higher, maybe 50-100mv more then you have previously set.
Step 8

The MAP/IAT controller box in the cabin

MAP/MAF SENSOR MOD- The last mod, (probably the most important) is your load sensor mod, aka the MAP or MAF mod. These sensors give the engine an indication of load by measuring the volume of air coming into the intake. Higher pressures mean more gas is needed, lower pressures mean less gas is needed. Simply put these sensors translate the need for x amount of fuel into voltages which are sent to the ECU.

With hydroxy we don't need as much fuel as we did for everything before the system, even under load, so we can safely reduce some of this fuel. Even better, with the CTS, IAT and O2 sensors now in agreement for a leaner mixture, tweaking the MAP/MAF should be a piece of cake. You can either build the LM317T voltage regulated MAP adjuster all over the net or purchase one and install it on the VREF line (NOT the signal wire) of a MAP. (usually 5v)I adjusted my VREF down to about 4.85v. Make it switchable as well so you can toggle between your adjusted MAP voltage and the stock 5v factory VREF.
For some MAFs it's alot more complicated. If the MAF has a VREF you can attack that, if not you can go for the fluctuating signal voltage and attenuate that with a POT, OR you can put a low resistance resistor (say 1-4 ohms)on the ground wire to generally knock the air values down. Generally speaking, you must find a way to reduce the air volume the ECU sees through either the MAP or the MAF sensor. You can do this electronically or mechanically.
Step 9

Burning the hydroxy back to water!

Congratulations! Now you have a complete HOD system installed and tuned the proper way. With regular maintenance of the system mileage gains should be stable. Now you can enjoy vastly improved fuel economy with your system and be assured it won't disappear within a few days. Proper tuning of all the ECU's various sensors is the key to making an HOD system give consistent mileage gains long-term. Thanks for reading and let me know how my guide helps.

Comments

djmikewalsh said

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on 10/29/2009 I learned from an article called "Tuning for Mileage/Sensor mods"

triathlete0621 said

on 10/29/2009 Would you recommend any particular article based on experience? Thanks

on 10/29/2009 Become a member at http://hhoinfo.ning.com

There's tons of stuff in the documents library there to assist with tuning. I can help you too. I'm going to also re-write this article to update it and give better tuning instructions.

on 10/29/2009 Where is the best place to find detailed directions for installing and tuning the MAF enchanser and the EFIE? Thanks

on 10/28/2009 Actually, it is a misconception that leaning be done with MAP and MAF enhancers. While they do lean the trim, they also advance the timing. They should be adjusted for a peak in power. If the O2 sensor readings don't match up to the load sensor readings for an extended period of time, the computer adds fuel to compensate. Use your EFIE to lean the trim. The O2 sensors are primarily in charge of how much fuel you use. Tune your load sensors to match how far leaned you are on your EFIE as best you can, while maintaining good power from optimized ignition timing.