Exhaust pipe and method and system for enhancing engine performance

Abstract

A double U shaped exhaust pipe having varying internal pipe diameters for increasing horsepower, designed within internal combustion engine vehicle racing or other rules that limit such features as overall size. A first stage portion of the exhaust pipe produces a first periodic flow of exhaust, with a vacuum pulse created where the pipe internal diameter increases upon the exhaust reaching a second stage portion. A third stage portion of the exhaust pipe produces a third stage periodic flow of exhaust upon the exhaust reaching an increased pipe internal diameter at a fourth stage portion. These periodic pulsed flows are matched to the opening of the intake and exhaust valves of the engine for a selected engine speed range. The matching of a vacuum pulse to the opening exhaust valve improves engine performance by drawing exhaust gases from the engine. The matching of a vacuum pulse to the opening intake valve, which overlaps with the exhaust valve being open, enhances engine performance by swirling or otherwise mixing intake air and fuel received into the engine, and by improving engine 'breathing' by increasing the draw of intake air and fuel into the engine. The exhaust pipe is particularly useful with small, single-cylinder flathead engines for racing vehicles, as well as other engines that do not naturally breathe well. One exhaust pipe described includes features or use with a muffler attached at the end of the exhaust pipe, and a second described exhaust pipe is intended for use without a muffler.