Warning HHO is very explosive.
The chemicals used can cause severe burns and
For me I got 10 to 15% better gas millage from 30 MPG to
35MPG on a 97 Saab, Problem was it
Slowly deteriorated with time giving less and less HHO gas.
This is ( to me ) a major problem.
MAY 2013 UPDATE
Since this was posted I have been working with water vapor
Presently I am using a ultrasonic humidifier powered by a 400
watt 12 volt to 110 vac converter to
generate water vapor and injecting it behind the air filter on
my 97 Saab. It really seems to work with my mileage
30 mpg to 35 mpg. Perhaps I am missing something
but this is the approach I would suggest.
Also installing a humidifier is a lot easier than the plates
and solutions needed for HHO.
In my case the generator is in the trunk and a 1 inch PVC pipe
runs under the car to the engine compartment.
OCTOBER 2019 UPDATE
I ran across a article on generating HHO and it said it
was important to use
distilled water to prevent deposits on the plates.
I wish I had done that back when i was doing this
It seems to be worth the effort.
This page includes two new techniques. One is
the use of a spiral plates to achieve a large plate area in a
Another technique we use is to use a DC current limiter to
provide a constant current that does not change with cell
temperature. It uses 4 headlight bulbs with
the 8 filaments wired in parallel to produce a non linear
About 57 Amps
required to produce 1 LPM. his is beyond the drain we
wish to place on a car's alternator but fortunately 14 volts
are far in excess of the voltage required to produce hho.
Thus it is possible to make 4 small
units each producing about 1/4 of the total and connect
them in series. This reduces the current drain to
57 /4 or 14
amps per litter of gas .
This unit is composed of 4 cells made from 3 inch PVC
pipe each 9 inches long. A pipe cap is glued on the
bottom and a rubber seal is used on the top. The rubber
seal is clamped in place to make a gas tight seal but still
allow it to come off in
the event of an explosion.
I used a 6 inch by 100 inch roll of 316 stainless steel
shim stock .007 thick. It was purchased from
Macmaster Carr. This roll was cut to eight pieces each
12.5 inches by
6 inches. The pieces were stacked on a plywood
form and holes to clear a number 8 screw were drilled to
hold the spiral in place. The dimensions required for
the holes are all measured from one end. The dimensions
( in inches) are 0, 0.5, 1.77,
3.24, 4.917, 6.783, 8.884,
The holes are about 3/8 inch from the top and bottom of
This is shown below.
The two spirals needed were made by curling each of the
stainless pieces on a length of 1 inch copper tubing.
Then they were held together with 1/16 inch wire welding
rod. A drill was used to insure that the holes
were all in alignment. Then 8-32 flat head nylon plastic
screws and nuts together with 1/4-20 nylon nuts used as
spacers were used to assemble the 2 spirals that lie inside
each other. Two pieces of 1 inch by 2 inch stainless
are used to connect to the copper electrical connectors.
This is all shown below.
A 1/4 inch pipe tap was used to tap a hole for a 1/4
inch pipe fitting that connects to 1/4 inch PVC tubing.
ELECTRICAL CURRENT FEED-THRU.
To make the current feed-thru gas tight 2 1/4 - 20 flat
head brass screws were soldered together.
Then 2 holes were drilled and countersunk. The
taper of the Flathead screws made a gas tight seal.
It was found necessary to protect the gas outlet from the
water KOH mixture. I used a length of 1/2
inch PVC pipe that was cut to 3.075 inches long.
The ends were rounded with a file and holes
drilled into the top and bottom. They are
Then the gas outlet is unscrewed and a C clamp is used to
distort the 3 inch tube to insert the tubes as shown here.
A current regulator was made from 8 headlight bulbs.
These had all 16 filaments connected in parallel. They
are shown here,
The completed box with the transparent cover looks like this
the meter reads militants which is equal to the current in
Now for installing. I used 2 lengths of 3 conductor
wire with all 3 wires in parallel and 110 colt connectors as
they were cheap.
Here are the 2 wires on the battery. the positive one
goes through a 40 amp circuit breaker. One wire goes to
the screw. The second
is soldered to a nickle. The nickle is then cut
flat with a hack saw and inserted in the connector
blades of the circuit breaker.
The 2 wires go to the trunk,
Where they go through the box to the four cells:
The crate prevents tipping over. A copper tube then
runs back to the air cleaner:
PS vehicle is a 97 Saab 900.