well well i know because i have tested and retested my 2002 volvo v70 estate with 153000 miles on clock definitely improved by between 3 and 7 miles to the gallon tested over 2 years 22 mpg to the best 30.5
LPG? by: granmar
Very simply "NO!"
LPG is NOT a fossil fuel! LPG burns quite efficiently, but not much gain in cost per unit of energy!
HHO or Brown's gas, etc is a CATALYST for the combustion efficiency of FOSSIL FUELS (PETROL [BENZINE, GASOLINE] OR DIESEL).
TRADITIONALLY, THEY BURN ABOUT 28 - 32% EFFICIENT… HHO can improve the efficiency burn up to about 92%… almost 3 times combustion manufacturers' builds.
Of course, the engine MUST be properly tuned and serviced.