VW's Clean Diesel Touareg
With 10 cylinders chugging out more than 550 lb-ft of peak torque, the turbodiesel in Volkswagen's first-generation Touareg was awesome. Climb any mountain? Hell, it could move any mountain. At least it felt that way.
Ah, but that was so 2004.
These days, things are different. A 10-cylinder torque factory just isn't in keeping with today's worldview. The economy's going in the tank, fuel prices are bouncing around like a misjudged ping-pong ball, and "green" thinking is pervading everything from water bottles to jumbo jets. No, VW had to change the diesel in its SUV, to hew not only to consumer tastes but also to federal emissions requirements, which have gotten a lot stricter since the mighty V-10 TDI roamed the land. Starting this spring, the new-generation Touareg will be available in the U.S. with a 3.0L V-6 TDI, an engine VW is calling "one of the most fuel-efficient and cleanest in the world."
Now,that sort of description is music to the ears of the environmentally conscious, but what about those interested in how the engine performs? Well, as much as we miss the Saturn V-like thrust of the Touareg's old diesel, we were very pleased with the new engine's drivability. Rated at 225 hp and an even more impressive 407 lb-ft of torque, the new TDI has plenty of git-up-and-go from a stoplight (VW claims 0-60 times of 8.5 seconds) and should easily tug trailers weighing the 7,716-pound tow capacity. We thought the diesel's output would give the Touareg's tow numbers a bump, but other factors--brakes, chassis--kept the rating the same for both gas and diesel versions.
At idle the new TDI exhibits none of the clatter or vibration of traditional diesels, and at highway speeds the engine is even quieter and smoother. The new TDI also enjoys better fuel economy than the Touareg's gas engines: 18 mpg city, 25 highway, compared to the 14/20 rating of the 3.6L gas V-6 and the 13/18 of the 4.2L gas V-8. With a 26.4-gallon fuel tank, the Touareg TDI has a range of more than 600 miles, allowing it to travel "from Kokomo to the Poconos" without refueling, says VW.
Unfortunately, our time in an '09 Touareg TDI was brief--just a few hours on pavement only. A more complete, off-highway test will have to wait.
One big question we didn't get answered is the TDI's cost. We're sure it will command a premium over gasoline versions, but we won't know how much of a premium until closer to its on-sale date. All VW is saying at this point is the standard P.R. boilerplate about its being priced similar to the competitors. In this case, the competitors are made by BMW and Mercedes-Benz, so we're not expecting the Touareg TDI to come cheap.
The '09 Touareg reminded us a lot of the earlier model that won our 4x4 of the Year award in 2004. Behind the TDI is a six-speed automatic transmission and a fulltime 4xMotion system, which makes the fuel economy an even bigger achievement. The four-corner air suspension is still available as an option and moves from 6.3 inches of ground clearance at the hunkered-down passenger-loading setting to 11.8 inches at the "X'tra" level. (Ground clearance with the standard steel suspension is 8.3 inches.) Inside, the Touareg is well laid out and comfortable, with VW's characteristic high-quality feel to the switchgear and upholstery.
VW worked hard to keep the new SUV from becoming a total boat anchor. The 90-degree block is made from vermicular graphite iron, which VW says weighs 15 percent less than cast iron. That construction, and the use of aluminum cylinder heads, keep the engine's weight just below 500 pounds. In fact, the entire Touareg TDI--including its engine and all emissions equipment--weighs just 50 kilograms (about 110 pounds) more than a comparable gas version. Speaking of emissions, VW's engineers fought them on several fronts, from the Piezo injectors in the common-rail fuel-injection system to the AdBlue tank under the spare tire, and earned the engine 50-state smog compliance. What's AdBlue? It's a urea-based fluid that's introduced into the Touareg's DeNOx catalytic converter to transform nitrogen oxide into nitrogen and water without any other nasty byproducts. The odorless and biodegradable AdBlue is refilled during regular oil-change intervals, "without requiring the customer to concern themselves," sniffs VW's press material. Hey, AdBlue is just 32.5-percent urea; the rest is water. What's the problem?
Diesel In The dirt
Volkswagen is proud of its new diesel technology, but rather than just sending out a press release and running some new ads, it decided to take it to the dirt and go racing in the Baja 1000. As many of you know, the Baja 1000 is an endurance race in Baja, Mexico. Each year it runs a different route, sometimes longer than a thousand miles and sometimes shorter. The 2008 race was 634 miles but still had a wide variety of terrain, from abusive rocky goat trails to fine-as-powder silt-beds.
Most Trophy Trucks compete with insane horsepower and big-block gasoline engines, but the VW Trophy Touareg was actually pretty modest, with just 550 hp and 625 lb-ft of torque. The power and torque change comes from a 5.5L V-12 clean diesel engine that uses similar technology to the V-6 engine in the consumer Touareg but is more akin to the engines that sister company Audi uses in its American Le Mans endurance racing series. The engine feeds a six-speed Xtrac manual transmission (again unusual from most of the Trophy Trucks) and then goes down to a 9-inch-style rear axle; like most desert race trucks, this one is only two-wheel drive.
Volkswagen entered the Touareg into the race this year with the goal of finishing, not necessarily winning. The maker succeeded with flying colors. The race went well, with no flat tires and only one small clutch problem causing a few hours' delay. But in the end, VW crossed the finish line, popped the champagne, and became the first clean-diesel to compete in and finish the Baja 1000.
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The purpose-built Volkswagen/Red Bull Race Touareg TDI Trophy Truck has a double-A-arm front suspension that allows 25 inches of wheel travel, and a four-link rear suspension with up to 30 inches of wheel travel. The suspension combines Fox Racing shocks, Eibach coils, and 37x13.5x17 BFGoodrich Baja KRT off-road tires. Chassis design and production were handled by Arciero Miller Racing, and the truck was driven by Ryan Arciero and Mark Miller in the Baja 1000.The Race Touareg TDI Trophy Truck has a wheelbase of 125 inches, an overall length of 213 inches, a width of 92 inches, and an overall height of 78 inches. It weighs 5,650 pounds.Because most diesel engines get better mileage than gasoline engines, allowing the vehicle to drive farther between fillings, SCORE, the sanctioning body of the Baja 1000, actually gave a fuel capacity restriction to the diesel VW. VW wasn't forthcoming with the actual amount of fuel or fuel stops it made in the race (the team will be back next year and doesn't want to give any useful information to its competitors), but we suspect that VW's tanks lasted a fair bit longer than those of its competitors, who ran big-blocks.