1995 Buick Riviera Owner's Manual - Page 220

3800 Supercharged (L67) Engine (Option) Your vehicle may have a 3800 Supercharged engine. Buick chose supercharging rather than turbocharging because Buick emphasizes smooth, refined power. The supercharger is a device which is designed to pump more air into theengine than it would normally use. This air, mixed with fuel, creates increased engine power. Since the supercharger is a pump and is driven from an engine accessory drive belt, increased pressure is available at all driving conditions. The powertrain control module (PCM), works with a vacuum control to regulate the increased pressure required during specific driving conditions. When this increased pressure or boost is not desired, such as during idling and light throttle cruising, the excess air that the supercharger is pumping is routed through a bypass. All of these controls working together provide high performance, character and fuel efficiency in the 3800 V6 Supercharged Buick engine. The power steering pump uses a remote reservoir mounted on the throttle and cruise control cable bracket. See "Maintenance Schedule'' in the Index for when you should check the fluid. F 1. Front Belt 2. Back Belt A. Alternator B. Power Steering C. Crank D. Supercharger E. Coolant Pump E Air Conditioning The Supercharged 3800 engine uses two accessory drive belts. One belt drives the generator and the power steering pump. The second belt drives the supercharger, coolant pump and air conditioning compressor. Each belt has its own tensioner and idler pulley.