ZL1 - it’s the hottest Camaro yet!

Published Feb 10, 2011

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It's the fastest and most hi-tech Camaro yet - and even its name has a story.

Meet the 2012 Chevrolet Camaro ZL1, officially the first model to carry that designation - yet it takes its name from the most exclusive Camaro in history, one that was never intended for production.

ZL1 was the code name for a 427 cubic-inch (6997cc), all-aluminium, big-block V8 developed for the CanAm racing series in the late 1960s, but which found its way into a small number of 1969 Camaros.

It was similar to Chevrolet's iron-block L-88 engine but the ZL1's aluminium block reduced its weight by more than 45kg. It was officially rated at 320kW, although well-tuned examples produced more than 370.

When the muscle-car war was at its peak in the '60s, enterprising dealers used GM's production order system to request bigger engines and other equipment that wasn't available in standard models.

In 1969 Illinois Chevy dealer Fred Gibb ordered 50 Camaros with the new ZL1 racing engine. Despite never being intended for use in a production car, Gibb's order was filled - but not before a few other dealers got wind of it. They ordered a few, too, and production totalled 69 Camaros - plus two ZL1-powered Corvettes.

Those special Camaros could run 11-second quarter-mile times but cost nearly double the price of a standard version, so they were slow sellers. More than 40 years later, however, they're among the most valuable collectors' cars, thanks to their rarity, exotic engine and “king of the hill” mythology.

And because most of them were used as drag racers, few remain intact today and even fewer have their original engine, making them all the more special to enthusiasts and collectors.

You won't find the legendary '69 Camaro ZL1 in any GM catalogue (officially, it doesn't exist!) but its 2012 namesake is an genuine official factory model, designed from the ground up to be the best Camaro Chevrolet could build - including magnetic ride control, billed by GM as the world's fastest-reacting suspension system.

It's built around the 6.2-litre LSA supercharged V8, rated at 410kW and 745Nm - that's a lot more than even the original ZL1 lump, thanks to an intercooled supercharger and special heat-resistant cylinder heads.

The engine is based on a aluminium block with 103.25mm cast-iron liners and a forged-steel crankshaft with a 92mm stroke, held down by six-bolt, nodular iron main-bearing caps. Even the flywheel is held in pace by eight bolts instead of the normal six.

On the crank are lightweight sintered-metal conrods and 9.1:1 compression-ratio pistons, cast in a special heat-resistant alloy for quieter running, rather than forged.

The high-flow aluminium cylinder heads are spin-cast - that means the molten alloy is poured into a rotating mould, virtually eliminating trapped air pockets. Special vanes are cast into the intake ports to induce swirl in the pressurised air/fuel mixture.

Huge valves (55mm intake and 40.4mm exhaust!) are actuated by a hydraulic roller-type camshaft ground for a relatively low 12.2 mm lift on both the intake and exhaust sides, with limited overlap for a broader spread of power.

The sixth-generation Eaton supercharger, with high-helix, four-lobe rotors, displaces 1.9 litres and produces maximum boost of 0.62 bar, which is fed through an aluminium, liquid-to-air intercooler, mounted on top of the engine with its own remote pump and reservoir, to a single 87mm throttle body.

Ignition is by motorcycle-type “stick” coils - each plug has an individual coil built into its cap - and the engine breathes out through special cast stainless-steel manifolds.

Sadly, it’s unlikely that we’ll be seeing the ZL1 in South Africa - unless Tony Yengeni decides he needs one as a company car.

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