PONTIAC VIBE OFFERS HIGH PERFORMANCE OPTION AND ALL-WHEEL DRIVE
DETROIT – Vibe will make its mark on the segment not only by offering unprecedented versatility in design but also by unleashing surprisingly high performance.
The performance model, Vibe GT, has a 1.8-liter 180-hp four-cylinder engine mated to a six-speed manual transmission – a powerful combination of 100 hp/liter of specific power output. The GT engine uses variable valve timing and lift (VVTL-i) and powers the Vibe from 0-60 mph in the low eight-second range.
The power boost comes from a combination of enhancements, including modified heads and the variable valve timing and lift system that increases the intake/exhaust lift at high engine speeds. The VVTL-i system is an advanced set-up in which intake-valve timing is continuously varied throughout the rev range by hydraulically rotating the camshaft relative to its drive gear. Each pair of intake and exhaust valves is actuated by a single wide rocker arm. At low rpm, that arm follows a short-duration, low-lift cam lobe via a needle-bearing roller for smooth low-speed operation. A second spring-loaded slipper follower floats against a higher-lift, longer-duration cam lobe. Above 6000 rpm, oil pressure (controlled by a valve at the end of the camshaft) pushes a sliding pin in the rocker arm beneath the slipper follower, and the low-rpm roller floats free of its lobe.
The 1.8-liter, DOHC all-aluminum four-cylinder makes 180 hp at 7600 rpm and 130 lb-ft of torque at 6000 rpm. It has a high-rigidity aluminum block, short stroke (bore & stroke 82.0 x 85.0 mm), large diameter valves and a high compression ratio (11.5).
The GT engine utilizes a new laser-clad valve seat technology. With laser-clad valve seats, as opposed to shrink-fit seats, high-strength steel is deposited by laser directly onto the aluminum head casting, then machined into place. This process allows the valve-face diameter to be increased, optimizing airflow through the valve area, improving intake and exhaust performance.
The GT engine is mated to a six-speed manual transmission. Vibe GT is one of the only six-speeds in the segment. The six-speed adopts a high sixth-gear ratio with close-ratio gears for first through fifth speeds to maximize engine performance. A smaller gear ratio is used for its sixth speed to help reduce noise and fuel consumption during higher-speed, freeway driving.
Base Powerplant Offers High-Tech Efficiency
Vibe’s base model powerplant is a 1.8-liter four-cylinder engine with variable valve timing (VVT-i) that makes 130 hp at 6000 rpm and 125 lb-ft of torque at 4200 rpm. The inline four is a front-mounted, transverse, pent roof design with dual overhead cams.
It features a bore of 79.0 mm and stroke of 91.5 mm. The aluminum alloy block weighs approximately 56 pounds (25.5 kg). Improved combustion, made possible by such features as variable valve timing, a diagonal squish combustion chamber and a high compression ratio (10.0), and reduced friction loss make the engine easy to handle at low and medium speeds and provide responsive acceleration. More compact structural components, such as the aluminum block and oil pump, make the engine compact and lightweight, contributing to low fuel consumption.
It will be classified for 50-state emissions, earning ULEV (ultra-low emitting vehicle) status, meeting both EPA and CARB ULEV standards. A five-speed manual and four-speed automatic transmission are offered with the base engine and the all-wheel-drive version will be only be available with the automatic transmission. The automatic is a compact, lightweight transmission with a high-efficiency torque converter for smooth and responsive shifting. The automatic shifter has a high-quality design with an overdrive switch and driving pattern selector.
The Safety of All-Wheel Drive
Vibe all-wheel-drive models are equipped with a viscous coupling, full-time, all-wheel drive system engineered for the base 1.8-liter engine. In normal conditions, nearly 100 percent of the torque is to the front wheels. When there is wheel slippage detected, torque can be redirected as needed.
The all-wheel-drive system is compact and lightweight and uses a two-piece propeller shaft with shell-type cross-joints and a hypoid gear type. The viscous coupling unit has a torque split function. This is a simple, efficient design that eliminates the need for a separate torque split mechanism.
When wheel speed difference between the front and rear wheels is minimal, as during normal driving conditions, torque generated by the viscous coupling unit is small, resulting in nearly all the torque being directed to the front wheels, giving Vibe the behavior and road manners of a front-wheel-drive vehicle. When differences in wheel speeds occur between the front and rear wheels while driving on a slippery surface, the viscous coupling unit transfers torque to the wheels with the most grip, creating all-wheel-drive traction.
The viscous coupling unit consists of an outer housing, an inner hub and a number of inner plates and outer plates splined into the outer housing and the inner hugs, where silicon fluid is enclosed. The outer housing is connected to the propeller shaft that rotates, in sync with the front wheels, and the inner hub is connected to the drive pinion gear of the rear differential that rotates in sync with the rear wheels.
Suspension Optimized for Crisp Handling, SmoothRide
The Vibe’s suspension is constructed for the optimal blend of crisp, sporty handling and a smooth ride consistent with Pontiac’s brand character. The front suspension is designed with a leading-arm MacPherson strut type with a high caster angle. The rear suspensions of the base and GT vehicles have a twist beam. It ensures ample wheel stroke, improving riding comfort and quietness and providing outstanding handling and driving stability.
All-wheel-drive models come with an independent rear suspension of a compact double-wishbone set-up, featuring optimized placement of the arms. This suspension improves ride comfort and provides outstanding handling and stability to complement the sure-footedness of the all-wheel-drive system.
The brakes are a vented front disc/rear drum combination except on the GT model, where they are four-wheel discs with solid rotors at the rear. Vibe models offer three types of wheels – 16-inch steel, 16-inch five-spoke alloy and 17-inch five-spoke alloy. Tires sourced from Goodyear and Continental include a 16-inch P205/55/R16 all-season tire and an optional Dunlop 17-inch P215/50ZR/17 summer tire.
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