Chevrolet Lumina Z34

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Chevrolet Lumina Z34.

The Chevrolet Lumina Z34 is the more potent sibling to the Lumina. In production from 1991-1994, this replaced the Monte Carlo to become the company's official car of NASCAR.

The Z34 had a Dual Twin cam V6, which produced 210 hp (157 kW) with 215 lb·ft (292 N·m) of torque. It had a 0-60 time of 7.2 seconds. The Z34 came standard with a sports tuned suspension as well as a handling package. The physical characteristics include a standard spoiler, dual exhaust, factory-installed body kit, sport bucket seats and hood louvers. The Z34 production was haulted in 1994 when the Monte Carlo came back the year following.

The Z34 was not a consistently problematic car, but it did have its faults. The doors were said to be much too heavy and large, which could cause future sagging. The engine is extremely cramped, making the vehicle rather expensive to be serviced. The door handles are prone to breaking because of their uncommon vertical orientation, and the dashboard often peels.

Origin of the Z34

In 1989 Chevrolet replaced the popular Celebrity and Monte Carlo with the Lumina, a front-wheel drive car using the GM-10 or W-Body platform. This mid-sized sedan was manufactured to follow in the Monte Carlo's footsteps of gaining the most NASCAR victories in history. Vast improvements in aerodynamics and body design helped support confidence when the Lumina was driven to victory a majority of the Winston Cup Circuit. Much of this sleek NASCAR design was translated into the Lumina Z34 when it hit the consumer market in late 1990. The Z34 put aggressive styling, a tame lion's exhaust snarl, and precisely tuned handling powered by the first American made dual overhead cam V-6 in the hands of consumers. While this car has the power and agility to match a Ford Mustang, it still seats five comfortably and has enough trunk space for a day of shopping. Overall, the Z34's upgrades in the body, interior, engine, and other areas add a performance punch to the standard Lumina.

Exterior of the Z34

The Z34 spices up the exterior of the Lumina with a collage of ground effects although paint colors are limited to white, red, black, gray, and light blue. The front fascia includes a low profile airfoil before the radiator and a closed grill with slotted turn signal openings. Ground skirts that run along the side of the car give the appearance of a lower ride. Louvered slots in the hood pull some heat out the engine compartment. The rear end of the car is enhanced with a wing and a bumper accenting the dual exhaust outlets. The Z34 nameplate is labeled proudly along the stripe in the manner of the Z26 and Z24.

Interior of the Z34

The interior of the Z34 has subtle changes compared to the Lumina. Both have common complaints: a tiny glovebox, small instruments, overly plump seats, no cupholder, and climate control buttons that require a stretch to use. Some critics are also disappointed with the heavy doors, the high mounted third brake light, and the difficulty in getting in the back seat. On the favorable side, one of the best aspects of he Lumina's interior is its leg and headroom for he driver and passenger. The Z34's driver seat has three adjustments, one to slide back and forth, one for back adjustment, and the third tilts the entire seat. The cloth fabric is Scotchgard protected to avoid annoying stains. The Z34 also offered an optional Bose stereo system. All factory Delco speakers were replaced by Bose with door speakers being installed rather than dash speakers. These are all driven by a Bose amplifier, which is tucked away in the trunk lid.

Engine of the Z34

The Twin Dual Cam V-6 is the most respectable upgrade in the Z34. GM's engineers used the same block as the 2.8-3.1 60 degree V-6 for this four cam achievement. They did this to get the performance of Japanese four cam engines while keeping prices reasonable. The TDC engine incorporates racing engine technology with its valve configuration to attain a 7000 rpm redline. Aluminum heads in a pent-roof design and valve clearance notches in the pistons also uphold the high-rever's capacity. To keep manufacturing new parts to a minimum, the TDC shares the same stroke (84 mm) as the 3.1-3.4's but contrary to popular belief it does not share the same stroke with the chevy 2.8l, the 2.8 has a 2.99" stroke whereas the other 60 degree v6's (3.1's & 3.4's) have a stroke of 3.31". The connecting rods and crankshaft are shared although the metallurgy has been altered to handle the additional horsepower of the 3.4L engine. Cylinder walls were thickened and bearings were reinforced and polished to handle the increased load. Improvements have also been made in the cooling system, ignition, and oiling system to accommodate more moving parts. For example, the Z34 has oil reserves in the valve train to reduce wear at start up, an oil to water cooler, and a windage trey to avoid foaming. This simplistic and reliable design puts out 210 hp (157 kW) at 5,200 rpm, an impressive 215 ft·lbf (292 N·m) of torque at 4,400 rpm, and a compression ratio of 9.25:1. Upwards of 5,200 rpm the fuel delivery is cut off and the valves float to avoid engine damage.

In order to accommodate the extra horsepower, transmission improvements were needed. The standard MG2 used in Luminas was upgraded to the Getrag 284 five-speed transmission with a final drive ratio of 3.67:1. The Z34 was geared for fast driving producing a remarkable 7.5 second 0-60 mph time and a 15.8 in the quarter mile. The four-speed automatic was also stepped up the Hydra-Matic 4T60-E from the ME9 but is half a second slower 0-60 and loses 10 hp (7 kW).

Small changes in the exhaust system reduce backflow pressure in the Z34. Both the Lumina and Z34 have a single catalytic converter but the Z34's exhaust utilizes two mufflers to release its gasses. A Y-pipe after the converter separates the rear-mounted mufflers producing a low rumble.

Because Chevrolet engineers realize that a performance car must not only go fast, tune-ups in braking, suspension, and steering were necessary. The FE3 sport suspension used in the Z34 incorporates a 34 mm (1.3 in) front stabilizer bar, a 12 mm (0.5 in) rear stabilizer bar, MacPherson struts, and leaf springs. The steering was also improved from that of the Lumina with a 14:1 steering ratio resulting in a 39 ft (12 m) turning radius. The Goodyear GT+4 225/60/16x6.5 tires also brought the Z34 to pull 0.79 g's (7.7 m/s²). Four-wheel anti-lock disc brakes were standard stopping the car from 60 mph (97 km/h) in 153 ft (47 m). Overall, test drivers were impressed by the consistency of the Z34 and its surprisingly well-rounded performance characteristics.

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