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Buick Park Avenue Ultra sedan boosts power with supercharger
Bob Plunkett
Date Posted: 5/10/2005
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SEDONA, Ariz. -- On a long airport taxi ramp in the red rock colony of Sedona, a driver hurled big American luxury sedans down the tarmac in tests to determine which is fastest from standing start to speed at 60 miles an hour.
Tally the number of cylinders in engines of these competitive sedans and from the outset you might well predict winners because two of the vehicles contain hefty V8 powerplants while the third draws from only six cylinders.
Yet analysis of test results reveal the fastest times -- by almost a second -- come from the sedan equipped with the V6 engine, which also produces by far the best fuel economy figures, by several miles per gallon.
How can a smaller engine beat the bigger ones?
An answer comes from a powerful idea: Supercharge it.
The fastest sedan in these tests, Buick's elegant flagship Park Avenue Ultra, uses a mechanical supercharger to increase horsepower from the 3.8-liter 6-cylinder engine.
Before attaching supercharger, the engine in conventional form musters 205 hp.
Add the supercharger and output climbs to 240 hp.
More importantly, torque generated from this horsepower -- the engine's muscle used to turn the wheels -- also climbs dramatically through supercharging, but at lower engine speeds, which means there's more strength available quicker through lower gears.
Maximizing engine output has long been a hallmark of the Buick Division of General Motors, and supercharged Buick engines trace to 1951 with a 335 hp supercharged V8 LeSabre show car and subsequent 1953 production model.
By applying a supercharger to a smaller engine like the V6 of Park Avenue Ultra, power and torque numbers climb significantly without adversely affecting fuel economy.
And supercharging amounts to a simple mechanical idea.
Essentially, a blower driven by the engine forces more air into each cylinder to enrich the mix of fuel and oxygen required for combustion. This boost of air in turn generates more power with each cycle of ignition without requiring more fuel to do so.
The supercharged 3.8-liter V6 of Park Avenue also shows up in two other models in Buick's stable -- mid-size Regal sedan and full-size Riviera coupe, although it is the full-size Park Avenue Ultra sedan that crowns this line due to spacious quarters and plush appointments.
Park Avenue emerged last year in new form riding on a redesigned platform derived from Riviera. Compared to the predecessor, this new version measures longer in wheelbase, broader in width and taller in stance.
This bigger-taller-wider approach to automotive design translates most significantly to more interior room in the front seat, with head space increasing by almost an inch and shoulder room enlarging by 1.3 inches. Rear passengers also get more room to stretch, with space for hips increasing by another 1.5 inches and leg room growing by almost an inch.
With so much improved space laced throughout the car, you might expect a hulk of a design outside, yet lines of Park Avenue remain similar to former versions, with a streamlined tapering prow followed by a massive windshield dramatically canted to maximize aerodynamic efficiency.
Behind the slipstream package, a new frame increases structural integrity for safety, improved performance and reduced interior noise. Windshield A-pillar supports, for instance, consist of tubular steel skewed in oval profile to magnify strength and increase visibility for a driver.
To prevent external noise from entering the cabin, door hinges on Park Avenue were fortified to stem eventual door sag and subsequent sound seepage.
To check road harshness and motion vibrations from intruding on passengers, the car's front and rear suspension systems now include rubber sub-frame pads which create an isolated cradle for suspension components.
But can a big car like this behave on the road?
Recent road tests on mountainous routes around Sedona reveal that Buick's ultimate sedan is smooth and almost effortless, yet quite aggressive when asked.
Then came a week at home steering a Park Avenue Ultra around city routes and freeway segments. During this time I found myself wallowing in the luxury of Ultra. It looks good, fits a full-framed body as only a full-size American car can, then piles on as many plush comfort trappings as anything on the road today.
Consider it a remarkably well-behaved full-size sedan outfitted with the luxurious amenities of a mega-bucks foreign machine but for a lot less outlay of cash with the initial cost as well as continuing operating expenses.
The two Park Avenue models vary primarily in power and on-board amenities, with the supercharger added to Park Avenue Ultra.
Either version links to a 4-speed automatic transmission with electronically-controlled shift sequences for unobtrusive transitions. This General Motors transmission, dubbed 4T65E, permits the application of more engine torque than its predecessor, which increases the floored-throttle shift point to 5700 rpm.
The base Park Avenue has a responsive power-assisted rack and pinion steering system, while Ultra borrows from Cadillac a Magnasteer variable-effort device that uses electronic controls for magnetic torsion to raise or lower amount of effort required to steer.
At lower speed, such as when parking, you'll feel less pressure so the steering wheel turns easily, but at higher speed on a highway pressure increases so only a slight movement of the wheel turns the car quickly.
Both Park Avenues carry power 4-disc anti-lock brakes, dual airbags and other safety features, all of the power and comfort figures you would expect on the finest luxury automobiles, plus GM's PASS-Key II theft-deterrent system.
A single key unlocks the ignition, side doors and rear decklid of Park Avenue. This may sound like a minor point but it has always amazed me why it took two different keys to operate a GM car. The single Buick key indicates that consumer-responsive changes are underway at General Motors.
Then Ultra sweetens its deal with more luxury gear like rich leather seat upholstery, automatic climate system with dual controls, analog instruments with tachometer, remote keyless entry, concert-quality stereo speakers, 6-way power controls for both front bucket seats, and more.
1998 BUICK PARK AVENUE ULTRA SEDAN
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| Vehicle Specifications: |
| 1998 BUICK PARK AVENUE ULTRA Specs |
| Description: |
Full-size luxury sedan |
| Model Options: |
Full-size luxury sedan |
| Wheelbase: |
113.8 inches |
| Overall Length: |
206.8 inches
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| Engine Size: |
OHV 3.8-L V6
OHV 3.8-L V6 SC
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| Transmission: |
Auto/4 |
| Drive: |
Front |
| Braking: |
Power 4-disc/ABS |
| Airbags: |
2 |
| Gas Mileage: |
Base: 19/29 mpg
Ultra: 18/27 mpg |
| Price: |
$ 31,200 to $ 38,400 |
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