Stampa la Pagina - [ENG] First Drive: 2006 Lexus IS 350

Edmunds: First Drive: 2006 Lexus IS 350 (http://www.edmunds.com/insideline/do/Drives/FirstDrives/articleId=106455)

Bigger, Faster and Packing Electronic Heat

By John Pearley Huffman
Date posted: 07-14-2005

Since 2001, the Lexus IS 300 has taken on the BMW 3 Series with marginal success. Although it never really lit up the sales charts, the rear-wheel-drive IS 300 has earned a small but loyal following. Young, too. In fact, according to Lexus, the median age of IS buyers is just 29. That's the youngest for any car sold by any luxury maker and decades younger than the median age for buyers of most luxury cars.

In the car business, young buyers are good buyers, but so are more buyers, so when it came time to dream up the second generation of the IS, Lexus had to design a sedan with expanded appeal that wouldn't disenfranchise the kids.

A tall order, but we think Lexus may have pulled it off.

The 2006 Lexus IS sedan is bigger, more luxurious and much more powerful than the car it replaces, and for the first time several models are available. Buyers can now choose between the Lexus IS 250, Lexus IS 250 with all-wheel drive and Lexus IS 350, all which get V6 engines and six-speed transmissions.

Lexus GS Jr.
Since Lexus already had an excellent rear-drive platform in its GS, it became the starting point for the new IS. By carving out 4.7 inches of the GS' wheelbase and lopping off 4.4 inches of front and rear overhang, Lexus had the basic structure of the new IS. Its 180.1-inch length makes it 2 inches longer than a 2006 BMW 3 Series sedan, but its 107.5-inch wheelbase is 1.2 inches shorter than the BMW's. The Lexus is also a little narrower and a little taller than the Bimmer.

The GS' double-wishbone front and independent multilink rear suspension moves intact to the IS and is retuned for the new application. Even the big 13.1-inch diameter ventilated front and 12.2-inch diameter solid rear disc brakes from the V8-powered GS 430 migrate to the new IS 350. The less powerful IS 250 uses the GS 300's slightly smaller discs.

The one significant piece of GS technology that didn't make it onto the new IS is variable-ratio power steering. Instead the IS has a speed-sensitive, electric variably assisted rack and pinion system.

Two New Variations on a Familiar Engine Family
The IS 300's straight six has been replaced by two new all-aluminum members of Toyota's latest family of 60-degree, DOHC, 24-valved V6s. The engines feature VVT-i variable valve timing and are already powering everything from the GS 300 to the base Toyota Tundra pickup.

The V6 in the IS 250 displaces 2.5 liters. Lexus rates it at 204 horsepower at 6,400 rpm with the 185 pound-feet of peak torque at 4,800 rpm using the SAE's latest rating regimen. An expansion in bore and stroke turns that engine into the 3.5-liter that powers the IS 350. It's rated at an impressive 306 hp at 6,400 rpm and a chunky 277 lb-ft of torque at 4,800 rpm. Both engines use direct gasoline injection with the IS 350's also having additional injectors in the intake ports to promote better fuel distribution when intake charge velocities are down.

Behind those engines are new six-speed transmissions. A true manual transmission, you know with a clutch pedal, is only available on the base rear-drive IS 250. If shifting isn't your thing, a six-speed automatic with a manual mode is optional. Order all-wheel drive on your IS 250, which by the way adds 216 pounds to the car's curb weight, or step up to the IS 350, and a six-speed automatic with a manual mode becomes mandatory. Lexus does supply paddle shifters just behind the steering wheel, but a real manual like you can get in a BMW 330i would be better.

The Nanny Factor
Also coming from the GS is the suite of electronic technologies ? traction control, stability control, Electronic Brakeforce Distribution, BrakeAssist and the conventional antilock brakes and such ? that Lexus groups together as the "Vehicle Dynamics Integrated Management" (VDIM for acronym lovers). VDIM is standard on the IS 350 while most of the technologies also come on the IS 250, the integration isn't quite so comprehensive.

With VDIM working, it's tough to see how anyone could get in trouble with a new IS 350 unless they aimed for a telephone pole. Of course, if they'd opted for the "Pre-Collision System" that integrates with the Dynamic Radar Cruise Control when they whacked that pole it would be in a car that had prepared its occupants by pre-tensioning their belts, preinitializing the BrakeAssist system, and even trying to apply the brakes itself.

During the collision the front passengers would appreciate their knee airbags and double-row curtain shield airbags, and that the front passenger's unique "twin-chamber" airbag spreads apart to reduce blunt impacts.

Driving Technology
As with the GS, there's no conventional key for the IS 350 as it senses the presence of an electronic fob that allows the car to be started with the press of a button. There's a suggestion of the original IS' trapezoidal instrument binnacle and its chronographic instrument faces, but the dash design is much more elegant and rationally planned. The seats are well shaped, the steering wheel is a neat three-spoke design, and the pedals are covered in aluminum plates. Unlike in the IS 300, the interior materials on the new IS are up to Lexus standards.

Lexus claims the IS 350 will rip to 60 mph in just 5.6 seconds and it's easy to believe because the engine produces gushers of thrust in near silence. This is an engine that delivers power seamlessly ? there's no point where the VVT-i "kicks in" or the torque drops off. The IS 250's V6 is just as creamy and only lags in terms of overall thrust.

We drove an IS 250 with a six-speed manual and IS 350 with the optional performance package around Southern California and the Willow Springs Raceway road course. Although we expected the smaller-engined model with the real manual transmission to be our favorite, it was the IS 350 we liked best.

The IS 250 cruises along freeways like the luxury car it is. The ride is controlled but soft. On twisting roads it sort of wafts along never doing anything that could upset the passenger cabin extensively. Exciting? Not really. But it is comfortable, reassuring and competent. Plus, the manual transmission in the preproduction machine we sampled shifted with long throws and hazily defined gates. Lexus says it will be better in production models.

On the other hand, with 18-inch wheels and more than 300 hp, the IS 350 with the performance package is an undeniable performance car. There's no discernable exhaust note, but the IS 350 builds speed easily, the chassis is tenacious, and if there isn't going to be a manual transmission around, at least the paddles add some involvement to the driving experience. There's no real comfort penalty for the big wheels and tires either, and turn-in is noticeably quicker than in the 250.

Still, there's so much technology aboard the IS 350, the driver is too insulated from the driving. The electronic throttle's response isn't as crisp as we would like, the transmission takes too long to respond to the paddle shifters and the steering is precise and quick, but hardly communicative. It's enough to make you miss the old IS 300's nervy, adolescent edge.

The biggest downer, however, is the inability to disarm the VDIM system, which mutes the sedan's performance long before the limits of its chassis and its optional 18-inch summer-spec tires are reached (17-inch all-weather tires are standard). There's a great engine, a great chassis and spectacular brakes under all that electronic baby-sitting, but the VDIM system is so intrusive it's hard to tell. We expressed a similar complaint about the GS 430.

A VDIM "Off" button would make this a much better sport sedan.

An Intimidating Competitor
With the structural heft of a beryllium atom, spectacular engines and exquisite assembly quality, the new IS is a car even committed Bimmer-philes should test-drive. It goes on sale this fall and should be priced competitively with, if not slightly below, BMW's 3 Series. It should be quite a sales race.

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Motori => Test su strada => Topic iniziato da: alura su Luglio 15, 2005, 10:12:23 am