Saturday, 8 October 2016

Water Doping, How It Works and DIY Experimental System

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You are probably reading this Blog because you have already heard of water doping or you are curious.

Basically, water doping is a method of introducing humid air into an engine to improve the engine efficiency, this leads to improved fuel economy, reduced pollution, longer engine oil life, reduced carbon deposits, cleaner DPFs and in some conditions an increase in torque.

Water doping is so simple that most do not believe that it can work or that it is beneficial to an engine.

After five years of using water doping systems on our own vehicles we can confirm that they work and we have experienced no detrimental effects on the engines, in fact quite the opposite.

This technique is not new and was used during WW2 to improve aircraft engine performance, the challenge has always been to make a system that is simple to integrate and maintain.

Through electrostatic charge from exhaust gas flow, water doping also polarises the steam droplets and mist which are sucked into the engine inlet along with the air.

The charged droplets (H2O) attach to the fuel droplets inside the engine and being H2O (Hydrogen and Oxygen) enhance the combustion of the fuel at the instant of ignition.

Some of the steam also gently removes carbon deposits to restore efficiency and the mist can improve the inlet air charge density (an inter-cooler enhancing effect). We also have seen water doping systems keep Diesel Particulate Filters (DPFs) clean.

We are keen to share our experiences to help others reduce their pollution, below we will explain how to make an experimental water doping system.


No Warranty is implied or given - if you experiment with Water Doping you are doing so entirely at your own risk.

The information provided is based on five years of private research and experimentation.

We have used approved water doping systems successfully for a five year period and over 50000 miles on our own vehicles and over 500000 miles on customer vehicles, with a good pollution reduction and fuel savings, with no adverse effects.

In short water doping can be successful, but results vary from engine type to engine type, the usage pattern, climatic conditions and the installation configuration.

Please also note that water doping does not work well on static engines/vehicles being tested on dynamo-meters as engines tested in these conditions are usually earthed and therefore do not enable the build up of electrostatic charge to help polarise the water mist/droplets.

It is possible to make your own water doping system without buying a kit, we will explain how to make a basic/experimental kit (which will require additional water level maintenance) but this will allow you to satisfy yourself that the principles work before deciding to buy a kit etc. A water doping kit which is proven is likely to be more successful than an experimental and a kit may be a better option if you do not have time to make parts and experiment, or you do not feel competent or confident to experiment with your engine.

What do You Need to Make

  • A device to make humid air, e.g. a bubbling container.
  • A mist heater/steamer, e.g. a heat exchanger attached to a hot part of the exhaust manifold.
  • Mist polarisation, achieved through the direction of gas flows (mist/air flow in opposite to exhaust gas flow).
  • Venturi to introduce the mist into the inlet and create a small vacuum.

Simple Experimental Hardware

  • Copper and brass plumbing pipe and fittings.
  • High temperature silicon hose.
  • Hose clips.
  • Container approx 1 ltr capacity.

Planning the Installation

The following points need to be considered:
  • Mist introduction point.
  • Short hose lengths to minimise loss of vacuum and air flow.
  • Container location, safe and secure, to enable topping up and to keep it warm (but not so hot that it could melt). 
Please bear in mind that this is a philanthropic act of sharing information to help everyone interested in using water doping to reduce engine pollution and save petrol/diesel.

How to make a low budget 


experimental DIY water doping system



No warranty is implied or given. Any experimentation you decide to undertake based on this information is done entirely at your own risk.

This part of the Blog explains how a budget water doping system could be made to satisfy your curiosity and prove that water doping works. It should only be attempted by a competent engineer who understands vehicles, engines and the terms used throughout this information. If in doubt do not take a chance. Read all of the information first and then plan as required.

This budget system is not meant to be a permanent installation, but it will allow you to make and test a water doping system before considering making your own system or buying one (or probably a hybrid DIY and a key parts purchase).


Parts required:

  • Qty 1 x Plastic bottle with large screw-on top e.g. 1 pint milk carton/bottle or a stronger bottle if possible
  • Qty 2 or 3 (depending on petrol or diesel installation) x reducing plumbing fittings 10mm to 15mm
  • Copper pipe sizes 10mm and 15mm
  • High temperature silicon hose with 10mm inside diameter and a minimum of 3mm wall thickness to avoid collapse under vacuum
  • Hose clips to suit outside diameter of silicon hose
  • Strong zip ties to secure the bottle in place
  • Qty 2 x hose clips to fit round the exhaust and heat exchanger
  • Qty 1 x high flow air filter/engine breather to clamp onto air inlet
  • Qty 1 x rubber grommet to seal inlet pipe into the bottle
  • Silicon sealer to make joints airtight (do not put on too much and wipe of any residue so it cant be sucked into the engine
  • Blunt vaping needle approximately 2mm outside diameter (for petrol engines only)
  • Vacuum hose 10mm outside diameter (for petrol engines only)


Tools required:

  • Hacksaw, suitable for cutting brass and copper
  • Files for removing burs and shaping parts
  • Screwdriver for hose clips
  • Method of flattening part of the 15mm copper pipe to make heat exchanger (hammer & anvil or a vice)
  • Spanners for tightening the plumbing fittings
  • Drill and drill bits for making holes (probably one stepped drill bit and a 2mm drill bit will suffice)
  • 1mm to 2mm diameter steel wire/rod to maintain air gap while flattening copper pipe to make heat exchanger

Plan the installation

Find the hottest part of the exhaust (normally the manifold), if possible chose a location next to the first lambda sensor (if the engine has one).

Find a location for the water bottle, ideally this should be somewhere warm but also accessible for topping up and not too far from the exhaust hot spot.

Select the mist introduction point, for normally aspirated petrol engines the engine breather pipe is usually the best point of mist introduction, for turbo diesel engines just before the turbo is good as this installation relies on air flow to create vacuum. Turbo petrol engines are difficult to get working properly so are probably best avoided at this time in your project.

You must avoid all moving and other hazardous parts. Also take account of engine rock during operation when routing hoses.

Make the parts



Mist outlet

Take one 10mm to 15mm plumbing fitting and remove the 15mm end nut and cut off the outer flange so that it can be used as a nut to clamp it to the cap (alternatively you can use packing washers to take up the gap).
Fix approximately a 50mm long piece of 10mm copper pipe to the smaller end of the fitting (this is to be able to connect the silicon hose to the bottle cap).
Drill a hole in the bottle cap and insert the fitting from the outside and secure on the inside with the modified nut and silicon sealant.

Air inlet tube

Take a piece of 15mm diameter pipe long enough to be inserted through the top of the bottle (at a point where the grommet can be fitted and sealed) to reach the bottom of the bottle and protrude sufficiently at the top to fit the breather/filter. Drill a suitable size hole in the bottle for the rubber grommet and fit the grommet with a small amount of silicon to make a good air tight joint.
Perforate the bottom end of the pipe with Qty six x 2 – 3mm holes suitably space in the bottom 20mm of the pipe (this is to create small bubbles which are better than big ones). De-bur all parts and remove any swarf. Insert the the pipe with the small holes at the bottom and seal to the gromet with a small amount of silicon sealant.


Heat exchanger


Check the available space on the exhaust hot spot, try to find approximately 150mm long area to clamp the heat exchange to. Cut a piece of 15mm diameter copper pipe to suit the space available less the length of two fittings (one secured at either end of the pipe). Secure the fittings to the pipe and tighten the nuts on the 15mm ends then remove the 10mm end nuts and olives. Insert two lengths of welding rod through the assembled fittings and pipe, then flatten the pipe using the rods as a guide, do this carefully as you need to be able to pull out the rods afterwards. Do not flatten right up to the fittings at either end as this will damage the air tight seal (stop about 30mm short of the nuts). Once the pipe has been flattened, gently bend (do not kink) it into a shape that enables the flat part can sit snug against the exhaust with the fittings standing clear to enable the hoses to be connected without fouling other parts. Once you are satisfied with the fit extract the rods. Clamp the heat exchanger in place with suitably sized hose clips (ideally stainless steel and these will be easier to remove later).


Petrol engine mist Injector


Take the vaping needle and insert it through the 10mm OD vacuum tube so that approximately 10mm of tube is exposed at the other end. Insert the assembled vaping tube and hose into the end of the 10mm ID silicon hose and secure it with a hose clip about 10mm back from the end of the silicone tube (to leave space for another clip) ensure that it has an air tight seal and cannot be sucked into the engine. Take another hose clip and clip two zip ties to the hose on opposite sides so that these can be used to secure the needle into the engine breather pipe. Pierce or drill the engine breather pipe and insert and secure the injector needle with a small amount of silicon sealant on the mating faces.


Diesel engine mist injector


Please note that you must not blank off more than 25% of the inlet hose/duct cross sectional area with the venturi.

Take a piece of 15mm pipe and cut half of it away (to make a half pipe venturi) for a length approximately equivalent to the inside diameter of the inlet duct/hose it will be inserted into, less 5mm (depending on inlet hose/duct thickness) to leave clearance on the far side and provide a circular sealing surface where it is inserted into the inlet duct/hose. De-bur and remove swarf as necessary. Trim and fit the pipe to a 15mm fitting so that a seating area just larger than the thickness of the wall of the inlet hose/duct protrudes from the fitting. Tightly secure the pipe to the fitting so that the pipe cannot be sucked into the engine. Fit the 10mm diameter copper pipe to the fitting and insert the pipe into the silicon hose. Secure the hose to the pipe with a hose clip and add a second clip to the hose closer to the fitting with two zip ties on opposite sides so that these can be used to secure the injector/venturi into the engine inlet hose/duct. Drill the inlet hose/duct to accept the injector as a snug fit, fully insert the injector with a small amount of silicon sealant on mating faces.


Connect up


Good unrestricted air flow is key to success. Hoses should be kept as short as possible and have no sag that could lead to water traps and ice plugs if weather is freezing over night etc. The hoses should also not be allowed to kink, add support if necessary but avoid clipping the hoses in a way that could restrict air flow.
The air flow through the heat exchanger needs to be flowing in the opposite direction to the exhaust gas flowing inside the pipe that the exchanger is secured to, so trim and connect the hoses with this in mind.
Take the hose from the mist injector and secure it to the the heat exchanger, connect another piece of hose between the heat exchanger and the the bubbler bottle top outlet.


Filling the system and testing


Fill the bottle with demineralised, distilled or rain water(depending on your installation it might be easiest done by removing the air filter/breather and pouring water through the tube) to approximately 25mm above the highest hole on the inlet tube (so that any air has to bubble through at least 25mm of water).
Start the engine and check that the system is bubbling (Diesel engines may not bubble until above approximately 1500 rpm, if it doesn't bubble then you might need to blank the EGR) and that the bottle is not collapsing etc.
Run engine until the engine it is hot, checking the security of parts etc. as necessary. Allow the engine to cool and then check all fittings are tight and secure. Test as you desire – if driving you should notice an improved driving experience, if you enjoy this too much you will not see a fuel saving as you will be using more power. 

Hopefully you will find this of some interest or use. Please don't wast your time adding critical comments as this is free information that could help some people to reduce engine pollution and save fuel on engines.

If you do make a saving on fuel, perhaps you would consider making a small donation, so that I can improve the system design and offer more free info. Leave a message sharing your experiences and let us know if you would like to donate or contribute positively to further developments in other ways.

If you are based in the UK and do not fancy making your own water doping system, you can purchase one from econokituk. Bespoke systems can also be designed/made on request e.g. for long range trucks, Porsche Boxsters and rotary engines etc.




I have taken some photos of various parts from my experimental equipment (more to follow when I find the other original parts from 6 years ago):

Example of 15mm to 10mm reducing plumbing fitting

10mm end of pipe fitted with silicon hose

Fittings in plastic bottle cap 

Using a larger cap size allows both fittings to be inserted in it so the bottles can be removed for easier filling. Also plastic pipe can be used for the fittings at the bottle end as it does not get hot, I used it for the inlet as it is easy to drill for the bubble holes.

Plastic tube drilled for bubbling

Ensure all swarf and burs are removed. The plastic tube can rest on bottom of bottle (but do not seal the end). The small tube is flush with the underside of the filler cap.

Cap assembly fitted to the bubbling bottle

I tried to find the most robust bottle and this on is a sample bottle, it is also the same diameter as most drinks bottles found on cycles so it could be mounted with the same sort of bracket (with an additional retaining strap to stop it jumping out of place).

10mm ID high temperature Silicon hose fitted over outlet tube

The 15mm plastic pipe can be fitted with a free flow engine breather/filter to stop ingesting particles if you run out of water. 

Add hose clips to all fittings and ensure there are no air leaks.