Four years down the line, Audi’s very successful A4 (B8 series) benefits from a mid-cycle refresh. But while the subtle changes to the car’s exterior make it look sharper and fresher, the big news is under the hood of the four-cylinder models where an all-new turbocharged motor lives.
While still designated 1.8 TFSI, the new motor comes in 120-hp and 170-hp flavors, and the 3.2-liter naturally aspirated V6 has been dropped from the range. That means there is now a big gap in the petrol motor lineup between the 211-hp 2.0 TFSI, the entry-level A4 model in the U.S., and the 333-hp 3.0-liter supercharged S4, which holds the fort until a new RS4 debuts next summer.
Compared to the 2011 MY car that wore the 1.8 TFSI badge, the benefits of the new motor are variable valve lift, a 10-hp increase to 170 hp, and torque is up from 185 lb-ft to 236 lb-ft. Fuel economy is 11 percent better, with emissions down by 21 percent, aided and abetted by the standard equipment start/stop system.
My test run across some very picturesque and hilly roads in Portugal soon proved the mettle of the new engine. In this front-wheel-drive model, the 236 lb-ft of torque proved more than enough to provoke torque steer in the lower gears, even in the dry.
On a twisty uphill road, I was reminded of why I do not care for powerful front-wheel-drive cars. Even in Third gear on a dry road, I could feel the torque steer accelerating hard out of modest bends. This would be a handful if driven sportingly in the wet.
This is a shame because the lusty new motor begs to be driven hard and enjoyed, and is also a smooth and economical partner when you are not pressing on. However, Audi will offer Quattro 4WD with the 170-hp motor before long, and I would not hesitate for one second before ticking the box.
Chassis updates are limited to fine-tuning of spring and damper rates, and the car rides just a tad better than before, enough to give it a big-car feel. The optional S-Line sport suspension brings stiffer spring and damper rates that drop the ride height by 30 mm to the same level as the sporty S4.
Another new feature across the board is the electro-mechanical power steering, which saves 11 pounds on the rack as well as aiding fuel economy. If you go for the sporty Dynamic Steering option, the system places a second motor on the steering column.
On the lighter side of medium weighted, the electro-mechanical steering filters out more road disturbance than the old hydraulic system without losing feel. Its 16.3:1 ratio felt just right when I was hustling on the hilly test roads.
One of the things I like about the supercharged 333-hp S4 is its duality of character. It can be sporting one minute and a refined cruiser the next, its engine a mere whisper in the background as you cruise along the motorway at 80 mph in top gear. If anything, the outside mirrors make more noise than the motor at that speed.
Throttle response is crisp, with the supercharger providing positive boost from off idle, it picks up revs quickly, and you feel a solid push in your back as the rev counter needle heads for the redline.
The updates to the seven-speed automatic gearbox, with its steering wheel paddle shifters, make for even faster and smoother shifts, and a totally seamless driving experience.
Coupled with the latest Quattro four-wheel-drive system sending more torque to the rear wheels, the S4 has less understeer and a better balance in the bends when you are pushing on.
The minor refinements to the spring and damper rates have made both the A4 and S4 feel more mature and more comfortable in both their primary and secondary ride when you just want to waft along.
Switch the Adaptive Damper Control suspension into its sports mode, the suspension tightens up enough to let you attack bends with real determination. This is especially so when you have the optional Sport Differential, available as an option on the S4, 3.0 FSI and 3.0 TDI models.
The revised grille design with chiseled top edges that first appeared on the A8 are reproduced here, flanked by a new headlamp design. If you order xenon lights, the LED daytime running lights are now in a strip that follows the profile of the lamp units, and the taillights get LED bulbs too.
Other than the optional climate-controlled comfort seats, and minor detail upgrades centered on the center console switchgear, the A4’s cabin is unchanged. As expected, the optional MMI system has been given all the functions that debuted last year like Google, local Wi-Fi hot spot and all the other convenience technologies.
The face-lifted A4 that goes on sale at the turn of the year remains a well-balanced car with best-in-class build quality. It still makes a strong case for itself, even against the all-new BMW 3 Series.
New 1.8 TFSI
I was so impressed by the new 1.8-liter four-cylinder turbo motor that I sought an in-depth interview with development engineer, Dipl.-Ing. Holger Nittel.
“It is the only all-new engine in the range,” he explained. “Sometimes it is actually more difficult to develop an existing engine to meet certain new parameters than to start from scratch, and this was one of those instances. So we made the decision to start with a new motor from the ground up that would be lighter, more efficient all round and easily able to meet the forthcoming EU6 emissions standards.”
The 7-pound saving is cumulative, and comes from careful design in all areas of the engine. The bore and stroke are the same as the previous 1.8 TFSI and the pistons are the same weight too, but of a newer design with a larger diameter gudgeon pin to better resist the greater torque of the new engine.
The block and cylinder heads are also new, and the cylinder head is a four-valve-per-cylinder design with chaindriven twin-overhead camshafts. Some of the parts around these major components are from the previous 1.8 TFSI and the 2.0 TFSI motors.
The Audi V6 was the first motor to feature direct fuel injection when it was launched in the A6 back in 2005. Since then, we have seen a lot of other manufacturers adopting this super accurate fuelling technology.
However, direct injection is most efficient during the start-up cycle and at high engine speeds, while the traditional multi-point injection is better for lower throttle openings.
So Audi have combined both FSI and MPI technologies on one engine. Look at a cut-away of the new 1.8 TFSI motor, and you will see a spark plug in the center of each combustion chamber with the direct injector offset to one side between the inlet valves.
The fuel rail for the MPI system, with one injector on each of the intake rails of the inlet manifold, as was commonly used until recently, is also there. Overall fuel rail pressure is 2,900 psi, up from 2,175 psi.
The water-cooling arrangements in the new cylinder head are also different, with the exhaust ports now water-cooled as well. Reducing temperatures in this area helps to reduce fuel consumption and emissions because in a turbocharged engine, some fuel is used for cooling as well as burning.
If the hot exhaust side of the head can be cooled, less fuel is required for cooling, which reduces fuel consumption. And less fuel consumption means lower emissions.
The turbocharger itself is a fixed-blade geometry unit from one of two suppliers and works with an air-to-air intercooler. To provide faster readings, the Lambda sensor is now on the turbocharger manifold rather than further downstream on the catalytic converter housing.
Another nifty trick for improving efficiency are the two rotary valves that turn the engine’s water-cooling system into a variable closed circuit loop. Normally, an engine is started and sends the coolant around a long loop from the radiator, through the engine and back.
Traditionally, a thermostat keeps the radiator out of the loop until the engine is warm enough to need it in the circuit. Now however, these two valves can make the water circuit even shorter around the motor so that it warms up faster, losing less energy in the process. Once again, this saves fuel and lowers emissions.