This is a common question regarding HHO kits. For years, the standard response seemed to all point to someone's conclusion that too much HHO actually makes you lose mileage, so you only need .5 to 1 liter max.
I'm not sure who actually decided this, but I'm pretty sure it was to offer an excuse for their poorly performing kits.
We found during real world testing in Brazil, that the OPPOSITE is true, IF you know what you are doing.
Case in point:
One of our tests in Goiania, Brazil, was a 2015 commercial diesel bus with a Euro5 engine (cleanest running diesel available). We were granted access to install and test a commercial unit. We initially inquired as to the size of the engine and were told it was a 14 liter diesel, so we brought our dual core commercial unit (with 2- 884 generators and custom built manifold, smart controller, larger reservoir and 4 levels of filtration). As we were finishing the installation, we found out it was actual only a 6.4 liter diesel engine – way smaller than we were anticipating, really only needed a single 884 unit. But we almost done, so we finished installation and started 2 days of testing. Same amps as other units- 18-20 amps.
When we were done, we had achieved 45% increase in the most efficient, EURO5 engine in Brazil.
So much for the idea of too much HHO being wasted. More on this later...
We will soon be making these available on our site as well - make sure to sign up to get notified if interested: HHOkitsdirect.com