VOLKSWAGEN Engine Modification: Description: Notes

Carburetor (or fuel injection) and distributor are set to maintain minimum proportions of carbon monoxide and hydrocarbon in exhaust. Ignition timing, temperature and engine condition are also of importance. A throttle positioner, on carbureted manual transmission vehicles only, opens throttle valve in accordance with intake manifold vacuum to prevent proportions of hydrocarbons in exhaust from increasing when vehicle is over running engine.