Since the Camaro's reintroduction a year ago many companies have had their crack at topping the SS (some even with a full warranty), but at long last it was GM's turn. And the General did not let us down. As GM's Ed Welburn and Rick Scheidt said when the 2012 ZL1 was unveiled, this is the most technologically advanced Camaro ever built, perhaps why only the ZL1 nameplate was sufficient for describing it. While it doesn't utilize an all-aluminum 427 big-block, or even its late model cousin-the LS7-it does have the most powerful engine ever dropped onto an F-body chassis at a GM assembly plant. The 550-horse 6.2L supercharged LSA engine is also one of the most meticulously designed and built factory engines, which lends itself to a high degree of durability and function. It's clear GM has set its sights on not just the Ford GT500 or even the Dodge Challenger SRT8, but on every sports car ever made or not made.
Starting first with the LSA's 3197T7 aluminum block, GM has a number of tricks up its sleeves. The cast-in-place (cast iron) cylinder liners receive deck plate honing, as you would on a high-end engine build at a custom shop, using billet aluminum plates and factory head bolts (torqued to spec) to simulate bore distortion. This process prevents scuffing by the pistons against the cylinder wall, and a more true bore means better sealing by the rings, which ultimately means more power, less friction and greater durability. GM started this on the LS7 and LS9 production and has been carried over to the LSA, where the final hone brings the cylinders to within 8 microns (.00031 inch) of its 103.25mm (4.06-inch) bore. Added to this precisely machined block are piston oil squirters, which will further aid to the longevity of the motor in helping to cool the low compression, high-strength alloy cast (hypereutectic) pistons. A forged crankshaft mated to lightweight powdered metal connecting rods gives thrust to the wet-sump LSA, and is lubricated by a special highvolume oil pump that has a pan-mounted cooler from which to draw its supply.
When combined with the L92-based heads, the LSA has a boost-friendly 9.1:1 compression. However, unlike its more cookie-cutter cousin, the LSA heads are a high-strength casting made of A356T6 alloy, for greater heat resistance, manufactured using the roto-casting method (like the LS9 heads) to virtually eliminate porosity. Premium steel 2.16-inch intake and 1.59 exhaust valves are used, and actuated by a low-lift (.480-inch) cam for smooth idle and low RPM characteristics. Unique 4-layer steel head gaskets are used so that the LSA can take all that the 1.9L Eaton can dish out. Many are already familiar with the sixth-generation, four-lobe blower from Eaton that is quieter and more efficient than ever thanks to its Twin Vortices Series (TVS) design. On the ZL1 it cranks out 9.0psi after passing thru its top-mounted liquid-to-air charge cooler. The cooler uses a dedicated circuit with a remote pump and reservoir instead of tapping the radiator. Exhaust is handled by a set of cast stainless steel manifolds, and a dual mode muffler setup similar to the Corvette.
Of course 550 ft-lbs of torque means the ZL1 requires a substantial drivetrain, and GM was quick to point out its advancements in this area including a 240mm dual-disc clutch, mated to a dual-mass flywheel and Tremec's stronger version of the TR6060 [aka "MG9"]. To better interact with the LSA's low RPM torque, the Z06 gear set was used in the 6060 as opposed to the more steep SS gears. The possibility of an automatic trans option, such as the 6L90E, hasn't been ruled out and appears under heavy consideration moving forward. Whether it makes production for the '12 model will remain to be seen. While specifics weren't given on the rear axle assembly, it was said to be a larger and stronger cast iron housing with stronger, asymmetrical axles. The axle design has been patented, and GM says it will negate wheel hop to the point of eliminating "torque-limiting electronics" (aka torque management). Other upgrades to the rear include a stronger limited-slip differential as well as a 3.73 gear ratio. GM denies that the housing uses the 9.5-inch ring and pinion, commonly found in GM trucks, but also said that it was in fact larger than the SS's 8.5-inch unit.
The suspension and chassis are just as advanced as the powertrain, boasting electric power steering, for enhanced feedback and more precise control, as well as Magnetic Ride Control. Much like the Corvette's, the ZL1's Magnetic Ride uses magneto-rheological science to vary shock dampening to optimize for either everyday street driving (Tour) or more spirited efforts (Sport). The rear sway bar (or stabilizer bar) has also been altered from the base and SS models, moving the drop links outboard of the control arms. GM says this provides more crisp response to driver commands, and can more effectively control body roll given the ZL1's increased limits. The spring rates and sway bar specs have been revised as well, though exact numbers can't be given as it may be subject to change as GM continues to the test the ZL1 on a variety of locations and surfaces. [At publication GM said they were closing in on the 80 percent mark of development and testing, with production slated for "early 2012."] Thankfully the increase in both unsprung and sprung mass is met with larger Brembo 14.6-inch, 6-piston front and 14.4-inch, 4-piston rear brakes (akin to the CTS-V). A newly designed forged 20-inch wheel saves weight while allowing more width for a meatier set of tires from Goodyear, which were specially designed for the ZL1 and based off the second-generation F1 Supercar tread and compound.