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Chevrolet Impala revision 2005

Last year, Chevrolet sold 290,000 Impalas in the America, making it the third largest selling car in the category just behind Toyota Camry and Honda Accord. The selling points of the car are mainly low price and practicality. However, as the even cheaper new Hyundai Sonata entered the scene, Impala may not retain the same sales result this year, even with the revision introduced in 2005.

The revision concentrates on 3 areas: 1) facelift, 2) new engines, 3) minor tuning and stiffening. The facelift is quite pleasing. It reshaped the nose and tail to look sleeker and smarter than the dull-looking old car. And then the front end structure is stiffened, the engine mounts improved and the suspension setup retuned to reduce noise and vibration. The result is a 50 kg increase of weight. The steering is also retuned to improve response and feel, though it will never be regarded as a driver's car.

Impala now adopts the new generation 3.5 and 3.9-litre V6s from Pontiac G6. Though both engines still employ push-rods ohv, 2 valves per cylinder and a heavy cast-iron block, they have a variable cam phasing system to improve efficiency. Power output is 210 hp and 240 hp respectively, considerably higher than the old 3.4 V6's 180 hp and 3.8 V6's 200 hp yet drink less fuel. However, while power matches that of the Japanese and Korean rivals, their smoothness and eagerness still lag behind the world standard.

Surprisingly, Chevrolet Impala re-introduces the SS badge with a new small-block 5.3-litre V8, codenamed LS4. The pushrod V8 pumps out a respectable 303 horsepower and 323 lbft of torque. It also has DOD (Displacement On Demand) function, which can shut down 4 cylinders to save fuel when the engine is running at light load. Even mated with a 4-speed automatic (compulsory on all Impalas actually), the V8 can push the 1682 kg car from rest to 60 mph in 5.7 seconds. This might match the slightly more powerful and slightly heavier Chrysler 300C, but don't forget the Chevy Impala SS is a front-drive car with all MacPherson-strut suspensions. That means horrible torque steer. The addition of V8 is more an advertising tactic than a call from keen drivers, who had all bought a Chrysler 300C, Dodge Magnum or Dodge Charger.

However, to comfort-seeking buyers, the Impala is quite satisfying. The Impala is always a big car with longer than average wheelbase. That is an inherent advantage to ride quality. Now with additional NVH suppression works, the cabin becomes remarkably quiet and the ride is pretty refined. The cabin also received a lift in materials and trim quality, plus more comfortable seats. In this way, most of the weaknesses of the original Impala has been sorted out.

The Impala is by no means outstanding, but it is not a bad car either. For those who care price and practicality more than image and driving pleasure, it is still a reasonable choice.
 
The above report was last updated on 4 Sep 2005. All Rights Reserved.
 

Chevrolet Impala SS

While you think the 268hp Camry or the 265hp new Altima the most powerful family sedans you can buy in the America, GM is putting a 303-horsepower, 323 lbft 5.3-litre V8 into the engine bay of Chevrolet Impala SS. Yes, it is the same “small block” push-rod V8 as last year’s Pontiac Grand Prix GXP. It wants to use astonishing grunt and tire-smoking acceleration to lure Americans back to the domestic brand. The Empire strikes back !

Patriots, don’t get excited so early. Although there is nothing wrong with the engine (apart from a little thirsty), the chassis fails to cope with the extra power and torque. The outdated W platform is not a good basis for a performance car. How can its front wheels, suspended by MacPherson struts, withstand the torque from a V8 engine ? especially when there is neither limited slip differential nor equal-length half shafts to relieve the torque steer ! and how to deal with wheelspin ? a traction control applies brake to the spinning front wheel, so the engine power shift discreetly from one wheel to another, ruining the steering.

You might remember Pontiac Grand Prix GXP employs wider tires up front than the rear to reduce understeer and a set of specially developed Bridgestone with stiffer sidewall to reduce torque steer. They work quite well in the Pontiac. Unfortunately, Chevrolet Impala SS gets none of these. Not just that, it even increased the final drive ratio from 2.93:1 to 3.29:1 in the attempt to improve acceleration further. This amplifies the torque steer and wheelspin problem. I think its project manager must be either ignorant or mad.

Another problem is the lack of suspension upgrade. The soft tuning leads to plenty of body roll and pitch to ruin any confidence. By the standard of fast-going family sedans its handling is already poor enough, let alone rear-drive rivals like Chrysler 300C. Other aspects are no better, ranging from the boring 4-speed automatic gearbox (still no manual mode) to the dull steering. The Impala SS must be developed at a very tight budget.

The only merit is the V8 engine. You can enjoy its lovely rumble-bumble and streams of torque on highway. If you can find a straight long enough, you can experience very strong acceleration too. But this talent is too limited. The bottom line is: GM has put a good engine into a wrong car.
 
The above report was last updated on 12 May 2006. All Rights Reserved.

Specifications

Model
-
Chevrolet Impala LTZ
Chevrolet Impala SS
Layout
-
Front-engined, Fwd
Front-engined, Fwd
L / W / H / WB (mm)
-
5090 / 1852 / 1490 / 2807
5090 / 1852 / 1490 / 2807
Engine
-
V6, ohv, 2v/cyl.
V8, ohv, 2v/cyl.
Capacity
-
3880 cc
5327 cc
Power
-
233 hp
303 hp
Torque
-
240 lbft
323 lbft
Transmission
-
4A
4A
Suspension (F/R)
-
All: strut
All: strut
Tyres (F/R)
-
All: 225/55R17
All: 235/50R18
Weight
-
1655 kg
1683 kg
Top speed
-
114 mph (limited)
154 mph*
0-60 mph
-
7.4 sec*
5.6 sec*
0-100 mph
-
20.1 sec*
13.9 sec*
AutoZine's rating
-
Click Here
Click Here
See illustration to spec.
Figures tested by: * C&D
 

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