Powering the base Grand Prix LE model in 1990 is a 2.3-liter 4-cylinder Quad 4, while a 3.1-liter V6 comes standard on SE and STE models. The V6 can also be ordered for the LE. The Quad 4 provides 160 horsepower at 6200 rpm and 155 pound-feet of torque at 5200 rpm. The normally aspirated V6 delivers 140 horsepower at 4800 rpm and 180 pound-feet of torque at 3600 rpm. A turbocharged version of the V6 is standard on the Turbo Grand Prix Coupe, optional for the STE sedan. The turbo engine cranks out 205 horsepower at 4800 rpm and 220 pound-feet of torque at 3200 rpm. The turbocharged V6 is replaced in '91 with a brand-new 3.4-liter, double-overhead-cam, 24-valve V6, and comes standard on the new GTP model. This engine delivers 210 horsepower at 5000 rpm with a 5-speed manual, 200 horsepower with GM's new electronically controlled 4-speed automatic. Torque is rated at 215 pound-feet at 4000 rpm. The new engine is an available option on all other Grand Prixs, except the LE sedan. Beginning in '92, the 3.1-liter V6 becomes the standard engine, replacing the 2.3-liter 4-cylinder Quad 4. For '93, a new 4-speed automatic transmission is available for the base 3.1-liter V6 as well. For '94, the base engine remains a 3.1-liter V6, but the entirely new design produces 20 more horsepower than the previous engine, with 160 horsepower at 5200 rpm and 185 pound-feet of torque at 4000 rpm. Also the optional twin-cam 3.4-liter V6 is upgraded in '94 to produce 210 horsepower with the 4-speed automatic, the same as when equipped with the 5-speed manual--dropped for '94--making the 4-speed automatic the only available gearbox, as the aging 3-speed automatic is also eliminated as member of the powertrain team.