A catalytic apparatus for efficient pre-combustion refinement of fossil fuel in vehicular engines, including an elongated outer metal pipe containing an elongated stainless steel inner tube of smaller diameter. The outer pipe is crimped or welded onto the inner tube to create a fuel chamber with connectors for the inflow and outflow of fossil fuel therethrough. The fuel chamber contains at least three catalytic elements each comprised of a different metal selected from the group Au, Cu, Ir, Ni, Pd, Pt, Zn and platiniridium, which may be electroplated small-pore screens. As engine coolant is diverted through the inner tube, excess heat is transferred to the inflowing fuel. The fuel is forced to flow in close proximity to the inner tube for maximum convection, and through the catalytic elements before flowing out through the fuel line to the fuel injectors for more efficient combustion.Also disclosed is a method of pre-combustion fuel refinement consisting of the steps of transferring excess heat from engine coolant through a tube disposed through an inlet and outlet of a fuel chamber. In the chamber the heated fossil fuel is forced through the catalytic elements described before returning to the fuel line for injection and combustion.