* Specific Supercharger: Different superchargers offer varying levels of boost. A small, low-boost supercharger might only add 50-75 horsepower, while a larger, high-boost unit could add 150 horsepower or more. The type of supercharger (roots-style, centrifugal, etc.) also impacts performance.
* Supporting Modifications: Simply bolting on a supercharger isn't enough. You'll likely need upgrades to the fuel system (injectors, pump), intake, exhaust, and possibly the engine internals (pistons, connecting rods) to handle the increased power and prevent damage. The quality and extent of these modifications significantly affect the final horsepower.
* Tuning: Proper tuning of the engine's computer (ECU) is crucial to optimize the air/fuel mixture and ignition timing for the supercharged engine. Without proper tuning, you risk engine damage and won't achieve the full potential horsepower.
* Condition of the Engine: The horsepower of the naturally aspirated engine before the supercharger installation also impacts the outcome. A well-maintained engine will yield better results than a worn-out one.
In short: You could see anywhere from a modest increase of 50-75 hp up to a significant gain of 150 hp or more, depending on the factors above. A realistic estimate for a reasonably well-done supercharger installation might be in the 150-200 hp range above the stock horsepower (which is approximately 190-200 hp for the 1998 4.3L). This still provides a significant range. To get a precise figure, you would need to specify the exact supercharger kit and supporting modifications.
