HHO Generators
HHO generators -- hydrogen generators to many -- work by a method called electrolysis. Water is split into individual components hydrogen (H2) and oxygen (O). These gases mix with the fuel in the engine and ignite, creating a higher octane fuel. The higher octane, in return, contributes to more complete fuel burning, reduced emissions, smoother running and the end result -- more miles per gallon for your car.
Sodium Hydroxide
The electrolysis process relies on the application of an electrical current inside the HHO cell. The cell contains distilled water and an electrolyte -- preferably sodium hydroxide (NaOH). While some use baking soda or potassium hydroxide (KOH), sodium hydroxide -- better known as lye -- is considered superior in performance to baking soda and more readily available than potassium hydroxide.
Calculating the Amount
Most cars operate efficiently when they produce 4 to 20 amps of electrolysis. This equates into, at most, 1/4 ounce (about 2 teaspoons) per quart of water, or 1 ounce (8 teaspoons) per gallon. Test the solution with a DC amp meter to test the amp draw: too high and the HHO cell will run hot.