Most people who dissmiss this never take into account that hydrogen is what is being combusted in the engine already, Octane is a HYDROcarbon and they never think to adjust the A/F ratio just like you need to do with any major mod to any engine. It's way easier on a carb and mechanical fuel injection. But you can build them pretty cheap but they are useless you can adjust you air to fuel ratio. I have an HHO on my car and didn't see and mileage increase but I did get a 14hp and 10ft.lbs increase
with no decrease in mileage, So I saw it as a plus! My grandpa had a pretty cheap wet cell he made out of a mason jar in a VW sports truck with mechanical fuel injection and was getting about 50mpg on the highway from 32mpg highway. Thats a pretty good set up PM if you want more info I have a bunch of pdfs on how to make a EFIE to adjust the A/F ratio and how to build HHO cells. And one liter is way stronger than wooden matches, I used to make mini hydrogen bombs and they were pretty damn strong, damn near killed a kid who tried putting his ciggerette out on a baloon filled with it. The slightest spark in a wet cell with have that thing in a million pieces in a second. Cells are pretty simple to make and are cheap the ebay and online kits suck. Really the only reason Hydrogen is being shut down if that it is too hard to capitalize on and they try to sell the hydrogen already split cuz nobody would be making money if they split it in the car. I am working on a magnet generator to power mine so I dont have to have any draw on my alternator. And having a higher load on the alternator doesn't reduce you mpg your engine is still pushing the same weight and would still be working just as hard if there was a lesser load on it. Anyone who says different doesn't know physics. The secret is to get an alternate power source to power the cell. A lot of cells don't even need more than 10 amps anyways.