RxP has something of a storied history, all with significant emissions reductions in vehicles that otherwise might not pass the sniffer. The website used to mention that it reacted with the "light" energy produced by combustion to basically cook latent deposits out of the combustion chamber area. Deposits which would be combustion by-products and let things "hide" in them so that more emissions would result. Getting them cooked out of the combustion chamber would result in less emissions.
RxP might help most vehicles, but it might help those engines with little turbulence in the combustion process (hence less "active" air and more deposit buildup in certain parts of the chamber) than engines that have more turbulent combustion (active air) combustion chamber dynamics.
One of the "cleanout" situations for vehicles (back in the 1960s) was to add a gallon of diesel to a full tank (usually 20 gallons) of gas as you started out of town of a long trip/vacation (where extended cruise periods at posted Interstate highway speeds would be the norm). It was supposed to be a way to get the carbon cleaned out of an engine that might normally see city or short trip driving. Couldn't do that very well with current unleaded fuel and sensitive emissions hardware, I suspect, but it worked for some people back then. Perhaps the RxP operatives have found a way to make a diesel-related additive that works in such small concentrations?
Willie Nelson's getting his bio-diesel plant cranked up pretty soon. Other plants are springing up too.
Just some thoughts,
CBODY67
