Last Updated: Aug. 31, 2017


Here are some answers to Frequently Asked Questions about Classic-HHO products. You can use the list of links to quickly navigate the page. Many answers can be found right in the Installation Manual provided with your Generator Systems and/or Electronic Devices. We can't stress enough how important it is to fully read the manual and understand it as best you can. There is also lots of great information in our Knowledge Base articles, as well. Please take some time to get to know this great technology. Of course, if you can't find the answer to your question, please feel free to contact us.

Getting Started


Electrolyte Solution

General & Other

Getting Started

Q: How Does HHO Work?

  1. This is actually a very commonly asked question, with a very common misconception of how HHO really works. We figured this would be best put on its own page. For an in-depth answer, please visit our How HHO Works page.

Q: What System should I get for my vehicle?

  1. This is the second most common question we get. Vehicle engines come in many different sizes, and with a variety of sensor configurations. Please feel free to email us at info@kempcospec.com with the full Year, Make, Model, and Liter Engine Size of your vehicle (i.e. 2000 Jeep Grand Cherokee 4.7L), and we will be happy to give you the best System Recommendation! Also, try our New System Recommendation Form.

    • For our "Wet" Cell style generators, we have found that a good way to match engine size with how many Cells are needed is to go with One Cell per Liter of Engine Size. Generally, that translates to 4 cyl. engines needing 1-2 Cells, 6 cylinder engines needing around 3-4 Cells, and 8 cylinder. engines needing 5-6 Cells. We recommend starting out with at least a 2-Cell System for the added benefit of a Multi-Cell System's divided "voltage-in." Depending on your vehicle, you may need an electronics enhancer device to manage the factory ECU (Environmental Control Unit or Electronic Control Unit). We carry four different types of EFIE (Electronic Fuel Injection Enhancer) devices to manage the O2 sensor signals to the ECU. You will want to contact us, with the vehicle information listed above, so we can check our databases for the correct device based on your vehicle's sensor configuration.

    • For a "Dry" Cell style generator, we offer a few different sizes to accommodate almost all vehicles. Dry Cells provide a different style of HHO delivery to the engine, though with basically the same concept. Check out our "Wet" Cell vs. "Dry" Cell explanation article, for more on the differences. The need for electronics to control the fuel injection, as outlined above regarding Wet-Cells, is relatively the same for Dry-Cells.


Q: Are these HHO Generator Systems safe for my engine?

  1. Yes. Our Systems are quite safe for your engine. In fact, introducing hydrogen to any internal combustion engine will assist the fuel (gasoline or diesel) in a more complete burn, thus reducing carbon deposits left behind on your pistons and valves. This results in a cleaner exhaust emission, as well as lessening the carbon footprint on our earth! Besides seeing better fuel economy, you will notice a more efficient running engine.

Q: Are these HHO Generators safe for diesel engines?

  1. Yes. Our HHO Hydrogen Generators can be used with a diesel engine. We actually have Wet Cell System Kits that come with Diesel Engine Hook-Up parts that accommodate diesel engines. And, the Dry Cell kits are adaptable to either Diesel or Gasoline engines. The addition of Hydrogen Assist Generators on diesel motors has proven to increase horsepower and maintain cleaner exhaust, as well; just like the gasoline engines. Can you imagine how much cleaner our air would be if every 18-wheeler on the highway employed one of these devices?

    You can find our Diesel Engine Wet Cell Kits in our store, here. For a Dry Cell Kit on a Diesel Engine, just match your engine size to the right Kit, and choose the MAP/MAF Enhancer option. You can find the Dry Cell Kits in our store, here.

Q: How well do these HHO Generators work on carbureted engines?

  1. These Generators are great for vehicles with carburetor engines. And, since most carbureted motors do not have an ECU (Environmental Control Unit), there is no need for an Electronics Enhancer. The Generators work equally as well on fuel injected vehicles. Although, with most newer engines that begin to implement some form of computer with sensors, the presence of an Electronics Enhancer may be required. An Electronics Enhancer will keep the ECU from negating the HHO System's output, and provide optimum savings and performance. For more on our EFIE’s see our document: EFIE Information.

Q: Do I need an EFIE?

  1. If your vehicle is factory-equipped with oxygen sensors, then there is a very good chance that you will need an EFIE (Electronic Fuel Injection Enhancer). We recommend these devices for virtually all American cars, foreign cars older than 1997, and most foreign cars after 1997 because most of these vehicles have oxygen sensors that need to be managed. Basically, an EFIE will keep the ECU from negating the HHO System's output, and provide optimum savings and performance. For more information on EFIE devices, visit our EFIE Information page. There are four different types of EFIEs that we provide, each of which is specific to particular oxygen sensor configurations found in various vehicles. Of course, if you are unsure of your vehicle's sensor configuration, and you need help choosing the correct EFIE, please contact us.

Q: Do I need a Pulse Width Modulator (PWM)?

  1. A Pulse Width Modulator, or PWM, will provide enhanced production without the worry of thermal runaway. For a complete, in-depth look at what a PWM is, and what it can do for you, we encourage you to read our Knowledge Base article titled "What is a PWM".


Q: How many more MPGs will I get if I use your HHO Generators?

  1. Depending on your vehicle, and Cell System in use, there can be anywhere from a 15% to 50% gain. Most people will see a 25% to 35% increase in MPG. Whether you chose a Wet-Cell System or a Dry Cell System you will see gains. Your particular vehicle, individual driving habits, and outside conditions can all play a factor in mileage gains, as well. It is probably most effective if your vehicle's engine is in good shape. So a tuned up engine BEFORE such improvements are made, will make sure you get the most out of your HHO System. Mechanical and electrical problems, such as malfunctioning sensors, worn engine components, loose wires, or leaky vacuum hoses are all culprits that will prevent fuel economy gains and must be fixed before you can enjoy the full benefits of Hydrogen Assist.

Q: What's the LPM (liters per minute) of one of the Wet Cell Generators?

  1. One Wet Cell Generator will produce up to 300 milliliters per minute. They average out at about 250mL per cell, though, under normal usage. Keeping a clean solution will increase the longevity of the cell, and keep it producing at optimal levels. Adding another Cell will more than double your HHO output due to the division of voltage across the Cells, which lowers the amperage allowing for more catalyst in your electrolyte solution. You can read more about the benefits of running a Multi-Cell System, here.

Q: Where is the best vacuum source?

  1. With Wet-Cells: We can either use a vacuum source on the engine to draw the HHO into the combustion chamber, or plumb straight into the cold air intake system. Plumbing into the cold air intake works best if the engine is turbo. This extra suction is enough to draw the HHO from this style of generator. We offer a Dual Supply Hook-Up Kit that hooks up to both manifold vacuum and to the cold air intake. For most vehicles, we have found the best vacuum source is to use the PCV valve line. You will need to locate your Positive Crankcase Valve in order to utilize its vacuum line. AutoZone's Website is a good resource for finding most vehicles component locations. You can also refer to the Question about what a PCV Enhancer is.

    With Dry-cells: It is straight into the cold air intake. Since the Dry-Cells create more pressure they can push the HHO instead of it needing to be drawn as with Wet-Cells.

Electrolyte Solution

Q: Is the Electrolyte Solution necessary for your Generators to function?

  1. Yes. Very much so. The Electrolyte Solution is needed in order to create electrolysis. Whether you choose Potassium carbonate for Wet-Cell Systems, or KOH or NaOH for Dry-Cells, it is most important to use only steam distilled water to mix the electrolyte solution. That way there are no unforeseen inconsistencies within the solution that could cause a breakdown of the electrodes, cause the Cell to overheat, and/or potentially damage the entire System. If you are thinking about just using tap water as your solution, consider the minerals in tap water to act as a catalyst. They are incalculable and ever-changing from day to day, and from tap to tap. We choose to use distilled water with the electrolyte, so we can have a measurement as a benchmark for amperage draw that we can maintain and or change to reach our objective (which is, of course, being able to produce as HHO, without overheating the cell units). Since this is not an exact science, we can use all the help we can get from our notes or benchmarks, and this is what we've come up with so far.

Q: What is the concentration of the Electrolyte Solution?

  1. For Wet Cells: The ratio for concentration of each jars’ electrolyte solution is determined by the desired amperage draw. This can be adjusted to meet that of your set-up. Multi-Cell Systems and alternate wiring schemes can require differing amounts of electrolyte, and starting reference points with tips and options, is included in our Instruction Manual. The amount of Cells in your System will determine the amount of electrolyte per jar. Pages 9-10 in the installation manual will tell you how much to use, based on your Cell set-up. If you are unsure of what to do here, or you did not receive our installation manual, please STOP and contact our Support Department regarding this matter. An incorrect concentration of Electrolyte Solution could lead to a breakdown in the electrodes.

    For Dry Cells: We recommend Potassium Hydroxide (KOH) and include the ratios in the Dry Cell Installation Manual. These ratios reflect not only the amperage draw relation, but also the freezing threshold of the solution for vehicles that will be operating in below freezing climate.

Q: Which Electrolyte is better?

  1. We have done testing with many electrolytes, including baking soda, potassium carbonate, potassium hydroxide (KOH), and sodium hydroxide (NaOH) also known as lye or drain opener. For Wet-Cells we recommend potassium carbonate and for Dry-Cells we suggest KOH. Drain cleaner can be used for the Dry-Cells but read the labels and make sure to choose one that has no additional additives.

Q: Can I use water from a faucet, or can only distilled water be used?

  1. Distilled water is necessary since the minerals in faucet water can act as a catalyst and speed up the electrolytic reaction. Plus, the additional minerals found in tap water can cause premature corrosion of the electrodes.

Q: What should I do to prevent the water/solution from freezing in the winter time?

  1. For Wet-Cells: You can use a gasoline antifreeze product called "Heet," which can be found at most auto parts stores, or online. The ratio would be 1 oz of "Heet" replacing 1 oz of distilled water in each jar filled to 24 oz. This should protect the Generator to about -10 degrees Fahrenheit (about -23 degrees Celsius). You may find that the solution is a bit slushy, but when you start up the Cells they will liquify quickly. If you believe that the Generator Cells could reach temperatures lower than -23 degrees Celsius, then you may want to look into Heating Pads, that are commonly used to wrap vehicle batteries in freezing temperatures, to wrap the towers in (most likely for overnight or extended periods of parking in such temperatures). Much like the idea of using a Core Heater for your engine block, or a household water supply heating element.

    For Dry-Cells: KOH at a 28% ratio will keep the Cell from freezing to -40 degrees Fahrenheit (also -40 degrees Celsius) more on this here.

Q: How often do I have to replace water/solution?

  1. For Wet-Cells: There is an initial start-up cleaning that should be done within 50 miles or 1 hour of first use. This will clean up any of the residue on the electrodes produced from manufacturing and handling. After refilling with fresh electrolyte you will just “top off” with distilled water (without electrolyte) when the level gets down to the first wind of electrodes exposed. That’s where our “top-off” bottle (included with our Hook-Up Kits) makes for quick and easy maintenance. Other than topping off, you will need to empty out each Generator and start afresh every few thousand miles, however, we like to keep our Generators running at top performance and replace about once a month.

    For Dry-Cells: Maintenance is at a minimum. Once you have the ratio set up to work for you, they can run for a whole year before replacing the solution.

General & Other

Q: I want to share my Installation and Results Success Story! How do I do that?

  1. Excellent! We want to be able to help spread the word for this amazing technology as much as we can. Simply email us at info@kempcospec.com with your Success Story and mileage results along with some pictures and/or video, and we'll consider it for our upcoming Testimonials section of our website. Good, high quality pictures and video will be the best. If you have any other questions regarding this, just ask! Happy HHO-ing!

Q: Is there a special fixture to secure the Generator System under the hood? And do you supply these parts in your "Hook-Up Kits"?

  1. For Wet Cells: Many items like cable ties, bungee cords, custom housing, and a bit of ingenuity can be used to secure your Generator(s). These are the only items we do not provide in our Hook-Up Kits because there are so many scenarios for individual vehicles, as well as personal preferences which we leave up to the individual. In our Installation Manual we give you some useful ideas to help with the mounting of the Hydrogen On Demand Systems that we sell.

    For Dry-Cells: There are mounting brackets supplied with the components and the hardware to fasten them in most cases, still a little ingenuity is needed to make room for and route the system as illustrated in the instructions provided.

Q: Do I need a relay switch?

  1. A relay is not really necessary until you start drawing more amps than the circuit you tap into is rated for. Most ignition systems are 15 amps, and you can check that by tracing to the fuse for the wire you plan to splice into. If you have a relay hanging around, it won't hurt to use it. If you're blowing the correct fuse for your system set-up, then you are either running too much electrolyte or have not wired your system correctly. Refer to your installation manual, for correct ratios and wiring schematics.

Q: What is a PCV Enhancer?

  1. A PCV (Positive Crankcase Ventilation) ports the pressure from your engines crankcase and returns it to the combustion chamber, therefore not being vented to the atmosphere (as most pre-1986 vehicles were doing). Using our PCV Enhancer device will clean the blow-by. It will reduce the oil that would normally re-enter the engine to be burned, which causes further buildup of the carbon deposits in your engine. So, essentially the PCV Enhancer "catches" this excess oil that would go back into your engine. Minimal upkeep is required. However, you will need to empty the oil cache about every two to three weeks (that is how much excess there is!). For an even more in-depth look at what Positive Crankcase Ventilation is, check out this wiki.