Car Craft
GMC Turbocharged/Intercooled 4.3-Liter V6
As the unofficial maximum-performance version of the Vortec V6, GMC’s turbocharged and intercooled Syclone engine is it small-displacement tactical nuke. In this high-output application, the 4.3’s gray cast-iron block is fitted with upgraded nodular iron main caps. specific intake and exhaust manifolding, a new EFI system, and cast hypereutectic heat-treated aluminum alloy pistons from the L98 Corvette. Attesting to the base 4.3 engine’s nearly bulletproof construction, the Vortec’s standard cast-nodular-iron crank, low-tension piston rings, wrist pins, roller lifters, hydraulic cam, and forged connecting rods are retained. The castiron cylinder heads also carry over from the base V6 but a special graphite composite head gasket with stainless flanges and annealed steel lire rings was specially developed by Victor Products to deal with its elevated cylinder pressures.
The same Bosch throttle body and top-feed pintle-type fuel injectors used on the L98 Corvette’s 350 V8 meter fuel to the Syclone V6 through a two-piece aluminum intake manifold. Engine management is via a speed density EFI system using a closed-loop engine module engineered by GM’s AC/Delco division. Electronically regulated by an integral wastegate to develop a maximum of 14 pounds of boost, the turbocharger itself is a Mitsubishi TD06 unit with it watercooled center bearing. In this limited-production setup, pressurized air from the turbo outlet is plumbed through a liquid-to-air intercooler before it’s fed to the throttle body and intake manifold.
