Just snip the fuel line in two and install a flow gauge in there. If hydrogen works, it should show up as slightly less fuel needed to push the engine against a brake dyno held at a certain speed.
which flow gauge? they aint cheap and usually they require a black box to supply you with meaningfull data, analog ones need to be installed in place to get real time readout...
I've talked to many hydrogen proponents, and the only ones who have any halfway sensible numbers to show are those using aftermarket engine management to "tweak" the engine to "optimize" running on hydrogen. The challenge is to show that the engine can't work at the "tweaked" settings without hydrogen boost, and that the fuel savings aren't simply due to running the engine leaner... which can be done in most cases on typically conservative factory fuel maps.
this would be the scenario in an indirectly injected diesel (mechanical injection pump) one fitted with turbo is even better. with humongous amounts of surplus air the addition of another fuel is easy to detect. diesels respond well to gasseous fuels standalone, or, in addition to #1 or #2 diesel. trickle a bit of flammable gas into the intake air tract and you will have additional power which will give you a lower throttle setting and or lower RPM. doesn't get any simpler. in case of HHO, preheating is very likely a requirement. it could be heated even more by introducing the gas pre turbo and although not likely, safety concerns might arise from doing so. perfect if the system lacks an intercooler. if the HHO is stored cryogenically it will require enormous preheating which could produce some challenges. onboard generation by deriving power from the main (propulsion) engine - even if just to supplement will not produce a smile from a fuel saving standpoint. i know a guy who did both HHO and propane supplementation in an 80's turbodiesel mercedes. will pick his brain...
All the doubletalk in the world can't cover up the fact that there is no dyno evidence and no scientific evidence for "HHO". On the other hand, there's plenty of evidence for meth-injection and water-injection (though water-injection benefits in terms of economy aren't really that big), which don't rely on hocus pocus to work.
water injection in gassers does all sorts of wonderful things:
allowing the use of poor gas, a bump in timing, more controlled burn, ability to lean AF ratio, delay/prevention of pre-ignition, valve cleaning, ring and c-chamber decoking... i have often mused what it would do for extreme lean burn. if i were to ever buy a honda it would be an HF!
I've got a dyno I can borrow, as well as AFR sensors and an OBD reader that can be hooked up for dyno-sessions. And I've got a car equipped with a stable aftermarket EMS for a test bed.
Every time I hear one of these outlandish claims locally (HHO, fuel line magnets, magic fuel additives), I tell them: Pay me for the dyno-time, and we'll test it. If your numbers work out, then I'll publish the results.
i would do it but it's a long drive
So far, no takers. Big surprise. Well... some of the additives do work, a little... but not as effectively as simply buying higher octane gas...
soltron can cure smoke in diesels but i have never used it in gassers.
which additives have you known to work? the few fuel injector cleaner additives that actually work - simply do so by allowing the injectors to work as intended. no magic in the bottle needed.
here in the USA some high end gasolines claim to have injector cleaners built in...