There are several known difficulties with running turbo-diesel engines with Hydroxy aka HHO (Brown's Gas).
However, installers who are successful got these mileage stats:
15.7 Miles Per Gallon (MPG) stock diesel
23.5 Miles Per Gallon (MPG) diesel with HHO * Turbocharger wear or premature damage * No mileage gain when running No. 2 diesel fuel * The manifold vacuum is insufficient to draw Hydroxy into the combustion chamber * After running with Hydroxy for several days/weeks successfully, idle becomes rough and black smoke exhaust appears * Keeping the lean MAF setting once the engine warms up
If you need help from consultants with these issues, try the Vancouver Gadgeteers club.
No mileage gain when running No. 2 diesel fuel on Hydroxyl HHO Brown's Gas?
phone 6 0 4 - 5 1 2 - 9 5 6 7