The 2015 Camaro Z/28
is the most track-capable model in its history, building on the legacy of the original SCCA Trans Am-series contender introduced in 1967. While the new Camaro Z/28 is not intended to compete in a specific race series, it is solely focused on track capability. In fact, its unique exterior is designed like a race car to produce downforce that presses the car against the track for greater grip – up to 1.08 g in cornering acceleration – and faster lap times.
Additional contributors to the car’s track performance included greater stopping power – the Z/28 features Brembo carbon ceramic brakes capable of 1.5 g in deceleration, and consistent brake feel, lap after lap – and reduced curb weight. The naturally aspirated Z/28 weighs 300 pounds less than the supercharged Camaro ZL1, with changes ranging from lightweight wheels to thinner rear-window glass. In fact, 100 percent of the un-sprung mass (suspension, wheels, tires and brake system) has been changed from the Camaro SS, dramatically enhancing the balance and overall driving feel of the Z/28.
“The Camaro Z/28 is an uncompromising performer that’s bred for the track – and every one of its unique components supports the goal of faster lap times,” said Mark Reuss, executive vice-president, global product development. “It takes the Z/28 back to its racing roots and adds to the strong lineup of Chevrolet performance cars.”
The Z/28 is offered in five exterior colors – Red Hot, Black, Silver Ice Metallic, Ashen Gray Metallic and Summit White – and only a single option is available: a package that adds air conditioning and the six audio speakers that are standard on the Camaro SS. The standard Z/28 package includes one speaker.
Exterior design and aerodynamics
With the driving goal focused on peak performance capability, engineers and designers looked for every opportunity to improve aerodynamics, powertrain cooling and brake-system cooling. As a result, the Z/28 produces 410 pounds more downforce than the Camaro SS at 150 mph.
The Camaro Z/28’s 7.0L LS7 engine is rated at an SAE-certified 505 horsepower (376 kW) and 481 lb-ft of torque (652 Nm), it complements the lightweight vehicle components to give the car its enviable 7.6:1 power-to-weight ratio – and deliver the power to accelerate strongly out of corners and achieve high straightaway speeds.
The LS7 was bred on the racetrack, with features designed for the high-rpm environment of the track, including a durable forged-steel crankshaft, lightweight titanium connecting rods and high-flow cylinder heads with lightweight titanium intake valves. It also features a racing-style dry-sump oiling system that helps ensure adequate oil pressure during high-load cornering.
A unique open air box intake system optimizes high-rpm airflow into the engine. It features a reusable K&N conical air filter and delivers the highest airflow performance of any production Camaro filter system. The air cleaner seals around bottom of the hood, reducing the chance recirculated hot air will be drawn into the engine.
The Z/28’s dual-mode exhaust system is engineered to provide high-flow and muscular sound character under aggressive acceleration, while attenuating noise levels in cruising conditions. It actively controls valves that change the flow path of the exhaust. With the valves open, the system produces less back pressure and more power from the engine.
A TREMEC TR6060 six-speed, close-ratio manual transmission backs the LS7 engine. It has a combination of double-cone and triple-cone synchronizers on all gears. Double-cone synchronizers have two friction surfaces to affect gear acceleration and triple-cone synchronizers have three friction surfaces – the greater the friction surface, the easier the transmission is to shift.
The transmission is used with a 5.1-ratio short-throw shifter that provides quicker, more precise-feeling gear changes – similar to ZL1 and SS 1LE models.
Performance Traction Management
Performance Traction Management (PTM) is an advanced system that integrates the chassis mode selection, Traction Control and Active Handling Systems, which are tuned specifically in the Z/28 for optimal road-course performance and consistency. PTM enables the driver to press the accelerator pedal to wide open at the exit of the corner and manages acceleration based on the given vehicle dynamics.
One of the sophisticated features integrated with PTM that help the Camaro Z/28 deliver faster laps on an undulating race track is dubbed the “flying car” logic by engineers. It is a feature for track use only that helps maintain the car’s full power and momentum, even if the tires briefly lose their contact with terra firma in certain track conditions. Without it, PTM would interpret the force reduction on the tires as a loss of traction and trigger torque reduction in an attempt to restore it – an intervention that would likely slow the car and reduce momentum.
PTM offers five performance levels, or modes, to accommodate a variety of driving conditions. The track-oriented “flying car” logic is available in all PTM modes, but it is most effective in Mode 5, which is calibrated for the fastest lap times.
Inside, the Camaro Z/28 features trim in a distinctive, matte finish, a flat-bottom steering wheel and Recaro seats with microfiber inserts. The seats feature aggressive bolsters for high-performance driving, as well as seat cutouts inspired by the five-point harnesses found on racing seats. To save weight, both front seats incorporate manual adjustment.
The rear seats of the Z/28 have also been modified for weight reduction. Nine pounds (4 kg) were saved by eliminating the seat-back pass-through, as well as using high-density foam in place of the rigid structure of the seat back and steel mesh of the seat bottom.