[GTPSPEED]

The LQ1 (also called the Twin Dual Cam) was a special DOHC version of the 3.1 L LH0 V6. It was built from 1991 to 1997. 1991-1993 it used tuned multiport fuel injection, made 200-210 hp @ 5,200 rpm and 215 ft. lbs torque @ 4000 rpm. 1994-1997 it used sequential fuel injection (SFI) making 215 hp @ 5,200 rpm and 225 ft. lbs torque @ 4,000 rpm. It has four large valves per cylinder. The 3.4 L uses a cogged belt to drive the four overhead camshafts. The gearbox options for the LQ1 were a 4 speed Hydra-Matic electronic shifting transmission and a 5 speed Getrag 284 manual transmission, unique to the LQ1. Adapting a pushrod block for overhead cams was difficult, and the 60° vee angle made this a very tall engine, but power output was impressive.

Bore was increased to 92 mm, but the 3.1 L engine's 84 mm stroke was retained. There are only a few interchangeable parts between this DOHC engine and other members of the 60° family, namely 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 shorter intake runners, cloverleaf combustion chambers, and larger "pill"-shaped exhaust ports. Camshafts and cam timing were also revised for the new, higher RPM powerband.

Applications:

1991-1994 Chevrolet Lumina Z34
1991-1995 Oldsmobile Cutlass Supreme
1991-1996 Pontiac Grand Prix
1995-1997 Chevrolet Monte Carlo Z34
1995-1997 Chevrolet Lumina LS