Impressed as we were by the driving qualities, technology and elegant, distinguished styling language and the excellent workmanship of the new Audi A4, we found it worthwhile to split up our driving reports of the different versions of this very able high-tech automobile in different parts. Here follows the second part… just enjoy it!
Hans Knol ten Bensel
Driving the Audi A4 2.0 TDI S tronic (140 kW)
Of course we were also keen to try out the front wheel drive version, with the 1968 cc four-cylinder diesel engine with VTG turbocharger, DOHC,TDI direct injection. (See the car on the photo above.)
The gearbox was this time the seven-gear S tronic, also with the fuel saving freewheel function.
A smooth performer, this four cylinder, with no vibrations whatsoever, despite its 400 Nm of torque, available over a very wide rev range between 1750 and 3000 rpm. Of course, 140 kW or 190 HP is still quite powerful and synonymous for excellent performance.
This A4 will sprint from 0 to 100 in a mere 7,7 seconds, hurtling further on to a top speed of 237 km/h. Audi quotes 4,1 litres/100 km of combined fuel consumption, CO2 emissions boiling down to merely 107 g/km. This version combines therefore superb performance with excellent consumption.
What modern petrol engines can do: we drove the 185 kW A4 avant 2.0 TFSI quattro S tronic
Having the velvet power of not less than 252 HP under your right foot, coming from a state of the art four cylinder two litre petrol engine is quite a special experience. This unit sports direct injection, exhaust turbocharger and Audi valvelift system for the outlet valves.
What do you think of sequential high-pressure direct and multipoint manifold injection with adaptive idle-charge control, overrun fuel cut-off, adaptive lambda control; mapped ignition with solid-state high-voltage distribution via single-spark coils, cylinder-selective adaptive knock control, manifold pressure measurement, active boost-pressure control via an electric wastegate actuator? State of the art, isn’t it?
Its technical refinements are further the exhaust manifold integrated into the cylinder head, the rotary-valve model for thermal management, and the dual fuel injection: under partial load, indirect injection in the inlet manifold supplements the FSI direct injection.
This means of course brilliant performance, all this combined with the petrol engined smoothness. The A4 Avant version we drove sprints here in 6 seconds to 100 km, and has an electronically limited 250 km top speed. This 2.0 TFSI delivers 185 kW (252 hp) and torque of 370 Nm (272.9 lb-ft) between 1,600 and 4,500 rpm.
The Sedan with front-wheel drive and S tronic consumes just 5.7 liters of fuel per 100 kilometers in the NEDC (41.3 US mpg) and emits 129 grams of CO2 per kilometer (207.6 grams per mile).
Clever combustion techniques…
Audi has introduced a new combustion method with shorter compression and longer expansion phases as well as increased compression, which is designed especially for partial load, by far the most common mode of operation.
The intake valves close much earlier than usual; in connection with increased pressure in the intake manifold, this reduces throttling losses during aspiration.
Due to the shortened compression phase, the compression ratio was successfully increased from 9.6:1 to 11.7:1. This means that in the compression phase, the engine only has to compress as much gas as a 1.4 TFSI.
Also in the expansion phase, in which it fully utilizes its two liters of displacement, it profits from the high compression ratio; the resulting higher level of pressure during combustion further increases the engine’s efficiency.
In order for the fuel-air mixture to swirl sufficiently despite the short intake time, the combustion chambers, piston recesses, intake ducts and turbocharging of the new 2.0 TFSI are specially adapted to the new combustion method.
Under higher loads, the Audi valve lift system opens the intake valves later, resulting in a higher charge, which ensures good power and torque delivery. Injection pressure has been increased to 250 bar…
Driving the A4 2.0 TDI ultra (110 kW): the frugal and “clean” bestseller…
Finally, we went back to basics with the 150 HP version of the popular 2.0 TDI engine. This A4 sported the “normal” 6 speed transmission and the “classic” dashboard with the two large round instruments for revs and speed. Not that this “basic” Audi is a sluggard: it will still sprint from 0 to 100 in 8,9 seconds, and reach a top speed of 210 km/h.
Of course, it is (very) frugal, with 3,7 litres on average in the combined mode, CO2 emissions being 95 g/km.
Driving dynamics and comfort are as described above, steering responsiveness also of very high order. A pleasant car to drive?
You bet. Its pulling power is also impressive: a torque of 320 Nm (236 lb-ft) is reached between 1,500 and 3,250 rpm. It is also breathing high tech: what to think of an engine features several sophisticated technical solutions – with separate cooling circuits, two balancing shafts in the crankcase, a cylinder-pressure sensor, substantially reduced inner friction and a common-rail fuel injection system with a maximum pressure of 2,000 bar.
Emissions stay this low thanks to high- and low-pressure exhaust-gas recirculation and multi-stage exhaust-gas after treatment including an SCR system (selective catalytic reduction).
Needless to say that were are keen to drive the Audi A4 in a more extended test, so stay tuned on these columns for further reports…
Hans Knol ten Bensel