3.4 L LQ1 V6

The LQ1 (also called the Twin Dual Cam or TDC) was a 3.4 L (3,350 cc) DOHC V6 engine ("X-code") based on the aluminum-headed second generation of GM's 60° engine line, sharing a similar block with its pushrod cousins, the 3.1 L LH0 V6 and the then recently retired 2.8 L (2,837 cc) LB6 V6. The engine was built only for front-wheel drive applications, and was featured exclusively in the first generation of GM's W-body platform. It was built from 1991 to 1997. From 1991 to 1993, it used tuned multiport fuel injection, made 200–210 hp (149–157 kW) at 5200 rpm and 215 lb⋅ft (292 N⋅m) of torque at 4000 rpm. From 1994 to 1997, it used sequential port fuel injection, making 210 hp (157 kW) at 5200 rpm and 215 lb⋅ft (292 N⋅m) of torque at 4000 rpm. In 1996, the heads were redesigned for better flow, as well as now making the engine an interference design and adapting the engine for federally mandated OBDII emissions. Output for the 1996-1997 LQ1 is 215 hp (160 kW) and 220 lb⋅ft (298 N⋅m). It had four valves per cylinder. The 3.4 L (3,350 cc) engine substituted the standard camshaft for a chain driven intermediate shaft, which drives four overhead cams via a cogged belt. Adapting the 60°pushrod block for the LQ1's overhead cams significantly increased packaged engine height. Bore was increased to 92 mm (3.6 in), and the 3.1 L (3,135 cc) engine's 84 mm (3.31 in) stroke was retained. Only a few interchangeable parts are use between this DOHC engine and other members of the 60° family, primarily the connecting rods and crankshaft. The heads and intake manifolds were redesigned for the 1996 model year, incorporating a larger throttle body and plenum area, slightly longer intake runners, cloverleaf combustion chambers, and larger "pill"-shaped exhaust ports. Camshafts and cam timing were also revised for the new, higher-rpm powerband. Optional from 1991 to 1993 was a Getrag 284 five-speed manual transaxle, which was also exclusive to the GM W platform and was available only with the LQ1. The electronically controlled Hydramatic 4T60-E four-speed automatic transaxle was the alternative, used during the entire production run with the exception of the 1997 Monte Carlo Z34 and 1997 Lumina LTZ, which received the 4T65-E.