review@drutx.UUCP (Millham) (04/23/85)
Here is an article from Popular Science Apr. '85. This should answer the turbo, super charger question. (reprinted without permission) Seven routes to higher performance: Turbocharger: A turbocharger is essentially a supercharger driven by a turbine in the exhaust-gas stream rather than by a belt drawing power from the engine. It is more efficient than a belt- or shaft-driven supercharger because is makes use of part of the 30 to 35 parcent of the heat energy a gasoline engine normally blows out of the tailpipe. Supercharger: In its broadest sense, a supercharger is any device that will force more air into the cylinders than would normally be drawn in by the vacuum created by pistons during the fan intake stroke. In most cases it is a mechanical pump or blower - driven by a belt from the engine - thet produces positive pressure in the intake manifold. Thus the engine gets more air, so it can burn more fuel and produce more power. Unfortunately, any belt-driven supercharger consumes power from the crankshaft. And although it produces more power than it consumes, it high boost pressures (higher engine speeds) this parasitic power loss can be considerable. (end) There is more about this. One point of interest: I remember a discussion about superchargers that stop drawing engine power when not needed - (no permission to print this either) But interest in supercharging is undergoing a revival. Bendix Corp., in a Society of Automotive Engineers paper, recently detailed a project using vane-type superchargers that closely resemble air-conditioning compressers. To increase mechanical efficiency of these blowers, an electrically operated clutch was installed in the V-belt drive pulleys to provide disengagement when the unit was not needed. ... Some engineers feel that if superchargers are to be efficient, they will require expensive electronics to control air bypasses and to cycle the V-belt pulley. One engineer felt that this could make superchargers even more expensive than turbos. (end) -------------------------------------------- Brian Millham AT & T Information Systems Denver, Co. ...!inhp4!drutx!review