you want to know the science behind HHO?
as far as experience goes, NO, i do not know of any pakwheeler with this kit.
i have seen the HHO advert on facebook several times.
to actually have a realistic test of this kit, would require two exactly identical cars completely brand new. one with kit and one without the kit. and then have a real world mileage test.
the kits are being installed in cars with vague maintenance history. something as simple as cleaning a throttle body, or reconnecting vacuum lines can increase the mileage of your car, which will give the user a placebo effect that its the HHO kit thats doing the mileage increase.
the science behind this kit is that HHO is produced using electrical power from the cars alternator. when the engine is running. this HHO is then injected into the intake manifold along with the fuel. so the car burns HHO and Fuel together. this results somehow in lower fuel consumption as claimed by the kit.
in its stock form, the car is running and consuming X amount of fuel. it provides power to the wheels A, alternator B and AC compressor C. the alternator consumes B amount of fuel to produce the HHO in addition to running the cars auxiliaries.
considering thermal values only, always remember that A+B+C will always be less then X.
and yet some how, the energy produced by B will reduce X.... the thermodynamics / law of energy conservation dont make sense.