history. The Camaro Z/28 is expected to be appearing at track events across the
United States in spring 2014.
“As the ultimate track-capable Camaro, this car restores the mission of the original Z/28, and serves as a testament to the expertise of Chevrolet as the best-selling brand of performance cars,” said Mark Reuss, president, GM North America. “The build sheet is the wish list of any racer: lightweight, high-revving, dry-sump LS7 engine; carbon-ceramic brakes; integrated coolers for track use; true aerodynamic downforce, and a significant reduction in curb weight. This car could only come from Chevrolet, and could only be called the Z/28.”
The first Camaro Z/28 was introduced in 1967, created to compete in the SCCA’s Trans-Am 2 Class. It featured a smaller, lighter, 302-cubic-inch V-8 for improved weight balance, as well as quick-ratio steering and a heavy-duty suspension for track use. In keeping with its road-racing focus, the 1967 Camaro Z/28, below, was not available with an auto transmission or AC.
While the new Camaro Z/28 is not intended to compete in a specific race series, it is solely focused on track capability. In initial testing, the Camaro Z/28 is three seconds faster per lap than the Camaro ZL1. That extra speed comes from three areas:
Increased grip: The Z/28 is capable of 1.05-g in cornering acceleration, due to comprehensive chassis revisions
Increased stopping power: The Z/28 features Brembo carbon-ceramic brakes capable of 1.5-g in deceleration, and consistent brake feel, lap after lap
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
“We set out to make the fastest road-racing Camaro possible that was still street-legal,” said Al Oppenheiser, Camaro chief engineer. “While the Camaro ZL1 offers exceptional performance on the street, the drag strip, and the track, the Z/28 is entirely focused on the track performance. The Z/28 will be too track-focused for most drivers, but offers road-racers one of the most capable track cars ever offered from an automaker.”
The Camaro Z/28 aerodynamic package includes a large front splitter, connected to an underbody panel that further reduces lift. In profile, the Z/28 features fender flares over the front and rear wheels, as well as extended rocker panels that contribute to aerodynamic stability. An aggressive rear spoiler and functional diffuser complete the aerodynamic package.
Inside, the Camaro Z/28 features trim in a distinctive, matte-metallic finish named Octane, the ZL1 flat-bottomed steering wheel, and standard Recaro seats with microfiber suede inserts. The new seats (also available on the coupe versions of the SS and ZL1 models), 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 adjustments.
The rear seats of the Z/28 have also been modified for weight reduction. Eliminating the seat-back pass through and using high-density foam in place of the rigid structure of the seat back and steel mesh of the seat bottom saved a total of nine pounds.
At the heart of the Z/28 Camaro’s track-capable performance is a 7.0-liter, 427-inch LS7. Like the original, the new Camaro Z/28 forgoes ultimate horsepower and torque for improved weight balance and track performance.
In 1967, the most-powerful engine available in a factory Camaro was a 396/375 big-block V-8. To prepare the original Camaro Z/28 for road racing, engineers specified a lighter, 302/290 small-block V-8. While the 302 was not the choice for drag racers, it proved ideal for sports car racing. Today, the most-powerful engine offered is the Camaro ZL1’s supercharged 6.2-liter LSA, which delivers 580 horsepower. The heart of the 2014 Camaro Z/28 is the lighter, naturally aspirated LS7, first introduced in the Corvette Z06.
“The LS7 is ideal for road racing because it delivers amazing performance in a compact, lightweight package,” said Jordan Lee, Small Block chief engineer and program manager. “The broad torque curve and high redline of the LS7 mean fewer shifts are required for each lap, while the lightweight design improves the front-to-rear weight balance for better handling.”
Co-developed with Corvette Racing, the hand-assembled 427-inch LS7 uses a number of high-performance components, including:
Titanium intake valves and connecting rods, and sodium-filled exhaust valves
CNC-ported aluminum cylinder heads
Forged-steel crankshaft and main bearing caps
High-lift camshaft
Hydroformed exhaust headers
11.0:1 compression ratio, and a 7,000-rpm redline.
10.5-quart, dry-sump oiling system
For the Camaro Z/28, the LS7 features unique induction and exhaust systems, and delivers at least 500 horsepower and 470 foot-pounds of torque. The racing-style, cold-air induction system and large K&N air filter provide maximum airflow. Its standard dual-mode exhaust system and larger-diameter pipes enable improved airflow. By bypassing the mufflers during acceleration, the system increases both the torque and sound.
The Camaro Z/28 is exclusively fitted with a Tremec TR6060 manual transmission. The six-speed features close-ratio gearing and 3.91:1 final drive ratio, both optimized for the power characteristics of the LS7.
Power is distributed to the rear wheels via a limited-slip differential featuring a helical gear set, rather than traditional clutch packs. The new design enables the driver to apply more power and get through corners faster, by continuously adjusting the torque bias to maximize available traction.The differential works in unison with Chevrolet’s proprietary Performance Traction Management system, which allows drivers to adjust the level of throttle and brake intervention to match their capability and driving environment.
Unlike some competitors’ “track package” offerings, the Camaro Z/28 makes standard all the cooling systems required for track use. This includes the dry-sump oiling system, connected to an integral liquid-to-liquid cooling system for engine oil. A second liquid-to-liquid system provides cooling for the transmission and differential. This system pumps overcooled transmission fluid to a heat exchanger in the rear differential before traveling to the transmission. This reduces differential temperatures as much as 100 degrees F. The singular focus of the Camaro Z/28 is most evident in the chassis, which delivers 1.05-g cornering grip.
“We used the very best components in the industry to deliver uncompromised performance, lap after lap,” said Mark Stielow, Camaro Z/28 engineering manager. “We made nearly 200 changes to improve the track performance, which cumulatively make the Z/28 capable of 1.05-g in cornering. For perspective, with all other things, equal increasing maximum grip from 1 to 1.05 – can cut up to four seconds per lap.”
The Camaro Z/28 is the one of the first production cars fitted with race-proven, spool-valve dampers. Compared to a conventional damper that offers only two-way tuning for bump and rebound, a spool-valve damper allows four-way adjustment to precisely tune both bump and rebound settings for high-speed and low-speed wheel motions.The wider tuning range allowed engineers to dramatically increase the damper stiffness on the Camaro Z/28 without a significant change in ride quality. Additional chassis changes include stiffer string rates and suspension bushings for improved cornering response.
At all four corners, lightweight, forged aluminum wheels are wrapped in massive 305/30ZR19 tires which reduce unsprung weight by 42 pounds per car compared to the 20-inch wheels standard on Camaro SS and ZL1. In addition, the smaller diameter
wheels lower the center of gravity by 33 millimeters, further improving handling.
This is the first production application of ultra-high performance Pirelli PZero Trofeo R tires, and believed to be the widest front tire on any production car.
To fully exploit the grip of the Pirelli tires, the Camaro Z/28 also features Brembo Carbon Ceramic rotors and fixed, monoblock calipers. The large 394 x 36-mm front rotors are paired with six-piston calipers, while the 390 x 32-mm rear rotors are paired four-piston calipers. Compared to similar-size, two-piece steel rotors, the lightweight carbon discs save 28 pounds per car. The combination of tire grip and braking power enable the Camaro Z/28 to achieve up to 1.5-g in deceleration. With standard front brake cooling ducts, the Z/28 is also capable of continuous track use unmatched brake feel, lap after lap.
To optimize the track performance of the Camaro Z/28, the engineering team subjected it to an intensive lightweighting program, saving 100 pounds compared to the naturally aspirated Camaro SS and 300 pounds to the supercharged Camaro ZL1.
“Our goal was to get rid of everything that didn’t make the car faster, and keep only what was required by law. For example, we wanted to eliminate the audio system completely, but we had to keep a single speaker for the seat-belt chime to meet safety requirements,” said Oppenheiser.
Other examples of weight savings include:
Eliminated the tire-inflator kit, except for Rhode Island and New Hampshire, where it is required by law
Removed interior sound deadener, and carpeting from the trunk
Replaced the standard LN4 battery with a smaller, lightweight, LN3 battery
Specified thinner, 3.2-mm glass for the rear window, compared to 3.5-mm glass on the standard Camaro
HID headlamps and fog lights are not available
Air conditioning is only available as a stand-alone option
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