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First Drive: Volkswagen Lupo 3L TDI
By by: Jamie Vondruska
Apr 3, 2003, 04:14

It wasn't long ago the European community thought the idea of a regular production vehicle that consumes 3 liters of fuel for every 100 kilometers was a mere pipe dream. A challenge was put out to European car manufacturers to produce such a vehicle and former VWAG Chairman Dr. Piech stepped up to the plate and swung hard - he usually didn't miss too many pitches when it comes to engineering feats. What resulted is the Volkswagen Lupo 3L TDI, the worlds first 3-liter consumption production car.

Positioned below the Polo in Europe, the Lupo is the lowest level Volkswagen model available today. At first glance though overall appearances can be very deceiving. The lupo has an enormous green house that makes the car appear very tall. Its width appears fairly substantial as well and gives the Lupo an overall decent stance. Until you look at the profile, particularly with the sudden end to sheet metal behind the rear wheels, you then realize how short the Lupo is in length. Overall though, if you put the Lupo next to a new Mini Cooper the Mini would appear smaller at first glance due to packaging perceptions.

With round projector style headlamps and a slippery smooth front end designed to cut through the wind, the Lupo has a very meek appearance that is altogether feminine but somewhat plain at the same time, owing to the very basic looking wheels and lack of any exterior frills - cute was the most frequent comment heard if anyone even noticed us.

So while the Lupo won't get you noticed, it does however bring serious tree-hugging credentials in the economy department. A 3-liter consumption vehicle roughly translates into about 78 miles per gallon of diesel - pretty darn impressive and a first for any manufacturer. So how did Volkswagen do it? How much time do you have?

Three cylinders, balancer shaft, direct injection with unit injector system, turbocharger with variable turbine geometry, charge air cooling, minimized frictional losses in the valve gear, bearings and pistons, and even an aluminum alloy cylinder block: The development engineers in Wolfsburg pulled out all the stops on this one. The result: the three-cylinder TDI achieves the highest efficiency world-wide for an engine of this type.



The 1.2-litre three-cylinder engine under the hood is the first diesel engine from Volkswagen (and the first diesel direct injector) to have not only its cylinder head but also its cylinder block in aluminum. At just 220 lbs. the three-cylinder TDI engine is one of the lightest diesel power units for passenger cars period.

Because of inherent design issues with a three cylinder design, Volkswagen used a balancer shaft to qwell vibrations and the result is an extremely smooth engine. Injection is via pumpe duse high-pressure unit injector elements arranged in the cylinder head and driven by the camshaft. The higher pressure permits a more efficient burn with improved performance and economy.

The 1.2l TDI also utilizes a Garrett turbocharger with variable-vane turbine geometry. At high revs and high load, the duct directing the exhaust gas against the turbine blades forces the variable-vane blades open to increase flow. Correspondingly at low-rpm's the vanes close to produce a smaller surface area with virtually no lag - it is almost like having two turbos in one package.

The 1.2-liter TDI has an output of 61hp and a maximum torque of 140 Nm (103 lb-ft) is available between 1,800 and 2,400 rpm. A pre- and main catalytic converter, together with exhaust recirculation, keep pollutant emissions down to an extremely low level.

While the above power figures don't give a good first impression, keep in mind the Lupo weighs in at only 1,882 lbs - over 1,000 lbs. less than a Golf 1.8T. According to Volkswagen the top speed of the Lupo 3L TDI is 165 km/h (102 mph) and acceleration from 0 to 100 km/h (0-62 mph) takes 14.5 seconds. The engine is not only unusually refined, but also has decent thrust. Volkswagen claims that the Lupo 3L can actually do better than 3 liters per 100 kilometers of consumption, although we were not able to test this as we were limited to 3 days of in-town driving since the low-sulphur fuel required for this car is not available here and VW only had limited supplies. None-the-less, we never saw less than 68 miles per gallon during all our around town driving - pretty impressive.



Fuel consumption as low as this leads to a problem in colder months: Not enough fuel is burned to provide effective heating for the passenger compartment. Volkswagen planned ahead though with an electric auxiliary heater that can pick up the slack where the standard system can't.

At the time we drove the Lupo, we were aware that it had a strange new transmission, but what VW didn't tell us till now is that it is in fact the new direct shift gearbox (DSG) found in the R32 and Audi TT 3.2, albeit with very different programming and one less gear.

In simplest terms, DSG is a dual-clutch electronically controlled transmission similar on the outside in appearances to a tiptronic automatic, but more like a manual gearbox mechanically inside - there is no clutch pedal. DSG utilizes 2 clutches, 2 main input shafts and 2 sets of gears - 1st, 3rd, 5th and Reverse on one shaft and 2nd, 4th on the other. What you see in the car looks very similar to a regular tiptronic gate with P, N, and E (for economy instead of drive) and a gate to the left for manual shifting.

Drop the transmission into the "E" position and it behaves very much like an automatic transmission except that the transmission always selects, independently of accelerator position and speed, the operating conditions of the engine which are most favorable for optimum fuel consumption. When you come to a stop the transmission goes into neutral and after 4 seconds of sitting the engine is shut down automatically. Lift off the brake and the car fires right back up and smoothly engages the clutch. A switch on the dash will defeat the automatic starting and stopping of the engine and adjust the shift program to something a little sportier if you need it. While driving if at any time the car is coasting the transmission will also go into neutral and the engine falls back to idle to minimize friction losses and optimize economy. All of this is seamless in operation and actually becomes easy to get used to since it requires no effort on the part of the driver.



In practice, direct shift has clear advantages: The engine is started with the brake pedal depressed and the selector lever in Park. In position "E" the car drives off when the accelerator is depressed, and the driver can select between the Economy and the automatic mode by means of the switch mentioned above. The battery and starter motor have been beefed up, to cope with the frequent starting. The latter is designed to handle more than 200,000 starts.

So the next question is what kind of diet did Volkswagen put the Lupo on to get the weight down? Practically all external body parts are different than the standard Lupo in terms of material and many elements of the structure under the skin have also been revised.

The front fenders, doors and hood are made of aluminum as are many interior components. Aluminum is used for the seat frames, and magnesium for the internal parts of the steering wheel. Aluminum is also used for the firewall, which replaces the bulkhead between the engine and passenger compartments. The frame itself has largely been changed to high-strength sheet steel, which meant that the wall thickness could be reduced.



Altogether 110 lbs. of weight has been saved on the body alone- without any sacrifices of torsional stiffness, long life or safety according to Volkswagen. With full-size airbags, head restraints on all four seats, multi-part safety steering column and collision protection elements in the doors, the Lupo 3L TDI possesses the same safety features as all other Lupos. It even has ABS with electronic brake pressure distribution as standard.
Smaller cooling air intakes in the front bumper, a streamlining of the sills, rear wheel spoilers, the largely flat underbody and the rear hatch extended at the top all help aerodynamic fine-tuning with a cd of 0.29 which is very good for a hatch.

The suspension systems of the Lupo 3L TDI - McPherson struts at front, torsion beam trailing arm axle at rear - have been largely redeveloped in the name of weight. Through the use of mostly aluminum components more than 132 lbs. of weight have been saved on the running gear.

At front the damper struts, the wishbones, the engine subframe and the brake calipers are of Aluminum On the rear axle, the trailing arms have been kept in steel. Coil springs and dampers, the latter in Aluminum, have been separated as on the base model - this separation giving more room in interior hatch space. The rear drum brakes are also Aluminum

The forged alloy wheels of the Lupo 3L TDI not only have a weight advantage, but also a visual one. They carry low rolling resistance tires (155/65R-14). Their belts consist of light Aramid fibres. These, together with the silicone technology for the tread, reduce rolling resistance by some 30 per cent according to Volkswagen.

Furthermore, springs, drive shafts, brake servo, pedals and steering column have been weight-optimized. Even the gas-filled struts which support the opening of the rear hatch and engine bonnet have been lightened, being constructed largely of Aluminum

The spare wheel has been replaced with a can of fix-a-flat and an electric air pump although there is room for a spare tire if you can bear to add the additional weight!

All windows are of thermal tinted glass, which for reasons of weight saving is thinner than normal. This alone saves 6.8 lbs.

In its interior equipment the Lupo 3L TDI is anything but a frugal economobile: The alloy doors have a sturdy feel, the seats are upholstered in the same material as the most upmarket Lupo version. All seats have adjustable head restraints, and the rear seats have Isofix mountings for two children's seats.



The dashboard has speedometer, rev counter, fuel gauge, clock and an on-board computer - this latter also displays both instant and average fuel consumption. The gear engaged is also displayed.

Typical Volkswagen attention to interior detail is shown even at this level with folding silicone-damped grab handles, sun visors with integrated make-up mirrors, folding rear seat backrest which can be fixed in two positions, numerous storage areas and chromed tie-downs in the hatch area.

The standard equipment of the Lupo 3L TDI includes:

Full-size airbags for driver and front passenger
Anti-lock brake system with EBPD
Electronic Stability Programme (ESP) including EDL and TCS
Alloy wheels
On-board computer
Electric auxiliary heating
Three-spoke, height-adjustable sports steering wheel
Automated direct shift gearbox with Tiptronic function
Belt tensioners and belt tension limiters at front
Rear head restraints
Isofix mountings
Bump strips, mirrors and door handles color-coded

Optionally, among other things the following items are available for the Lupo 3L TDI: Power-assisted steering, sliding sunroof, side airbags, air conditioner and navigation system.

Overall the Lupo still has a lot to offer even with its obviously small-size and basic looking exterior. Passenger accommodations are very good up front and decent in back however hatch space is at a big premium - two bags of groceries barely fit next to each other.



Conclusion

With all the economy minded features the Lupo 3L TDI is by no means a hot-hatch - for that there is the Lupo GTI. The low roll-resistance tires on the Lupo 3L TDI are very hard and give up the ship fairly early if pushed. The suspension setup combined with the cars short wheelbase and very tall profile all contribute to high body roll, although it never feels out of control or sloppy. Ride is firm but not harsh and the suspension soaks up bumps fairly well - you can tell this is a light-weight car.

People buying this particular Lupo model probably aren't too concerned about high performance driving antics and in that realm the Lupo 3L TDI delivers with tremendous economy, fairly decent road manners, a very livable interior and the satisfaction of knowing you own one of the most economical cars money can buy.


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