Audi A4

	Audi A4
	Debut: 2015 Maker: Audi Predecessor: A4 (2007)

Published on 25 Sep 2015

This is the 5th generation Audi A4, or the 9th if you include its predecessor Audi 80. Since the first 80 introduced in 1972, some 12 million units of the family have been sold worldwide. Moreover, it gets more and more popular in recent generations, rising from an also-ran in the class to one of the cars every buyer should consider. The 9th generation continues this trend. In many areas it has been improved considerably. However, as in the cases of many recent Audis, I am not quite sure if its styling can be described as progress. At the first glance, it looks as if a facelift of the old car rather than an all-new design. While the hexagonal corporate grille and polygonal headlamps are new, the rest of the car doesn’t differ much from the old. In fact, it could look more conservative than its predecessor from some angles, because its roof line gets straighter and its boot lid gets flatter. Its conservative approach is a sharp contrast to the ones taken by its rivals, especially Mercedes and Lexus. Perhaps it cares too much about the Chinese market.

Dimension-wise, the B9 model doesn’t differ much from its predecessor either. Measuring 4726 mm long, 1842 mm wide and 1427 mm tall, it is just marginally longer and wider than the outgoing model, while the 2820 mm wheelbase is barely 12 mm longer. However, I can’t help wondering how efficient it is. Here, I am not just talking about the efficient use of fuel but also the efficient use of materials, forms and technology. From its slightly bland appearance you won’t believe it has managed to match Mercedes CLA180 for a drag coefficient of 0.23, which means it is the smoothest production car in the world. It achieves that with smooth undertray and shutter grille but, unlike the Mercedes, without sacrificing rear headroom. This is efficient.

Likewise, without resorting to an aluminum-intensive chassis it manages to equal Mercedes C-class or even undercut Jaguar XE on scale. Look at the picture below, you will see the use of aluminum in the monocoque body is fairly limited. The majority of it comprises of high-strength or ultra-high-strength steel, which is cheaper to source and cheaper to assemble. Admittedly, the monocoque contributes to only 15 kg of weight saving. Audi seeks more weight saving in areas costing less to do, such as the aluminum-intensive suspensions (-13 kg), new electric power steering (-3.5 kg), seats (-9kg), magnesium-casing manual gearbox, hollow shafts and smaller clutch (-16 kg combined), lighter brakes (-5 kg)... as a result, an A4 1.4 TFSI weighs the same as a Mercedes C180. It is also 90 kg lighter than its direct predecessor.

The new A4 sits on an evolution of the existing MLB platform, or MLB Evo. Its 5-link front suspension is vastly reworked with lightweight forged aluminum links/knuckles, vibration-absorbing hydro-mounts and is mounted on a stiffer subframe. Likewise, the new 5-link rear axle is lighter than the old trapezoidal-link. There are 2 choices of suspension setup, one stiffer to please motoring journalists who consistently rated the A4 below BMW 3-Series, and one softer to please the majority of customers. Both can be optionally installed with adaptive dampers, which are linked to the Audi Drive Select system. As always, front-wheel-drive is standard on all models bar the most powerful ones, which are served with 40:60-split Quattro system.

At launch there are 7 engines on offer. The base A4 employs 150 hp 1.4 TSI ACT engine which is popular in Volkswagen group. Most customers are likely to opt for the mid-range 2.0 TFSI in two states of tune (190 hp or 252 hp), or the 2.0 TDI with 150 hp or 190 hp (don’t worry, it is the new EA288 instead of the emission-cheating EA189). At the top, the 3.0 TDI V6 offers either 218 hp or 272 hp and chunks of torque. All diesel engines are now EU6-compliant, thanks to AdBlue urea addictive.

The most interesting to me is the 190 hp 2.0 TFSI, because its operation can switch between Otto cycle and fuel-saving Miller cycle. In the latter mode, it utilizes the second cam set of Valvelift system to close the intake valves earlier, thus reduces the effective displacement to about 1.4 liters. With a CO2 rating of 109 g/km, it is the closest thing to replace diesel. Other engines are expectedly good.

Unlike the exterior, the cabin is a revolution. Its new dashboard design looks cool, high-tech and high-quality. I think it sets new standards for this class, beating even Mercedes C-class. The optional, 12.3-inch TFT instrument screen comes directly from Audi TT, so it may double as sat-nav display. The cabin also enjoys more space. Front passengers are given 11 mm more shoulder room and 24 mm more headroom, while rear passengers have 23 mm more legroom. 4 adults should find plenty of room, although 5 could be a bit tight.

Cruising on motorway, this cabin is what a relaxing place to spend time! There’s precious little wind and road noise thanks to the stiffer body and improved insulation, including double-glazing front windows. The engine, no matter petrol or diesel, is remarkably quiet on steady cruise. Ride quality is much improved from the old car, suppressing bumps and expansion joints far more effectively, although Mercedes or Jaguar seemed to have an edge when dealing with rougher surfaces. Refinement also extends to the slick 6-speed manual gearbox (a vast improvement from the old unit) and the class-leading 7-speed S Tronic twin-clutch.

Attacking corners, you will be amazed that the Audi’s handling is no longer troubled by strong understeer. Over the last couple of generations it had been cutting understeer gradually and now it steers almost as neutral as its rear-drive rivals. Although the engine still occupies the front overhang, its reworked front suspensions and steering makes it feel less nose-heavy. The front wheels grip harder and the nose follows your commands more faithfully.

However, the A4 still fails to match the dynamics of its rear-drive rivals, especially Jaguar XE, Cadillac ATS and the updated 3-Series. Its steering lacks the precision and feel to engage its drivers. It rolls more in a corner, and ultimately it doesn’t adjust its orbit when you back off mid-corner or try to have its tail unstuck. Its handling remains one-dimensional, which is all about grip and security. Quattro or front-wheel drive, this character is deeply printed on its DNA. Perhaps that is why all serious contenders for dynamics laurel opted for longitudinal engine and rear-wheel drive. Before the Audi makes that switch, which is unlikely in the foreseeable future, it will be hard to fight for the class leader title, even though it does many other things brilliantly.

Verdict:

Published on 16 Jun 2016

Audi S4

8 years ago, Audi declared supercharged V6 was the best engine configuration for its S4 after it had experimented also naturally aspirated V8 and turbocharged V6. Now it eats its own words by adopting V6 turbo on the new generation S4! If you doubt if it is really better, read the following numbers:

Maximum power: 354 hp, an increase of 21 hp from the outgoing supercharged V6.
Maximum torque: 369 lbft, up 45 lbft.
Rev at which max torque is generated: from 1370 to 4500 rpm, vs 2900-5300 rpm.
Fuel economy: 37.6 mpg combined, up from 29.1 mpg.
Engine weight: 172 kg, down 14 kg.

Such a sizable, all-round improvement made me speechless...

More research into this motor will find it is probably the most advanced production V6 currently on offer. Codenamed EA383, it is believed to be part of the new modular V6 / V8 family jointly developed by Audi and Porsche, which has been unveiled recently by Porsche in the form of 4.0-liter V8. Naturally, the Audi V6 shares the V8's 90-degree architecture to allow it to be built on the same production line. This necessitates a balancer shaft to be added at the center of the block, just above the crankshaft, to cancel vibration. It also shares the reverse-breathing architecture with the V8, which means the exhaust manifolds exit from the inside of the V and feed the turbocharger, which is also located in the V, through very short paths. Whereas the V8 employs twin-turbo, the S4 engine makes do with a single turbocharger (twin-turbo should be reserved for the RS4, of course). It is a twin-scroll turbocharger. Each of the scrolls is fed by the 3 cylinders of each bank in order to minimize exhaust gas interference thus improve turbine response. In addition to the relatively small turbine and very short exhaust manifolds, no wonder the engine can deliver maximum torque from merely 1370 rpm, which is just 670 rpm above idle! Turbo lag? There is hardly any!

Surprisingly, the V6 shares the bore / stroke dimension of 84.5 x 89.0 mm with the outgoing supercharged V6 rather than the 86 x 86mm of Porsche V8, so its displacement is exactly the same as its predecessor at 2995 c.c. However, its compression ratio is lifted from 10.3:1 to 11.2:1 to enhance combustion efficiency. Like the recent 190 hp 2.0TFSI engine, the V6 is capable to run in Miller cycle under part load to save fuel. This is implemented by Audi’s Valvelift system on the intake camshaft, whose second set of cams close the intake valves earlier and therefore reduce the effective intake stroke. At higher load where more power is demanded, it reverts to Otto cycle combustion and the full 11.2:1 compression ratio. No wonder fuel consumption is reduced by as much as 23 percent. Besides, the new engine cuts cold-start emission by separating the water cooling circuits of cylinder heads and block, so that the heads can be warmed up quicker.

No question this is a good engine. Working in tandem with the ZF 8-speed Tiptronic transmission and Quattro 4-wheel-drive system, the S4 is capable to do 0-60 mph sprint in 4.5 seconds (Avant takes an extra 0.2s), which beats not only BMW 340i (4.9s) but also Mercedes C43 4matic (4.7s). Drinks less and runs faster than rivals, well done!

Unfortunately, the rest of the car is less appealing. Exterior styling? Somewhat boring and somewhat bad taste (mainly its face). Interior? Extremely advanced and high quality, but so is the lesser A4! Aural excitement? The exhaust note is subdued and not very interesting. The gearbox? No more manual box or dual-clutch S tronic this time. Even though the Tiptronic is smooth and rapid, its gearshift is neither as responsive nor as satisfying as the dual-clutch when you are in mood to have fun. The steering? Light and direct but short of feel.

The new S4 have all kinds of ingredients to succeed, ranging from a Torsen C Quattro system (40:60 split normally) to optional active rear differential, from a 23 mm lower and stiffer suspension tuning to optional magnetorheological adaptive dampers. But wait, aren’t them already available to the last S4? Yes, that’s the problem. Audi spent little effort to improve its handling. It just lets the new A4’s superior refinement to erode the last S4’s fine dynamics and communication (it got a 5-star rating and matched BMW, remember). The result is a car excels more in comfort than driving excitement. No matter the steering, the gearshift and suspension, it has softened the edge and added an extra layer of isolation. Even that excellent turbocharged motor cannot claim a throttle response as instantaneous as the old supercharged V6. In short, the S4 is too civilized and too cold to inspire keen drivers. It lacks the tactile feel and deep engagement you would find in a 340i, C43 or Jaguar XE S. Faster, more refined and efficient it might be, it is not a great driver's car.

Verdict:

Published on 15 Dec 2017

Audi RS4

Turbocharged V6 might be less frenetic, but it suits the character of the Audi estate.

This is the 4th generation Audi RS4. The original car was born 17 years ago. It employed a mighty, 380-horsepower version of the company’s 2.7-liter twin-turbo V6, far exceeding the contemporary BMW M3 and Mercedes C55 AMG. It was the car that lifted Audi above its German rivals in the performance world. The next two generations RS4 were even better, as they switched to a high-revving (8250 or 8500 rpm) 4.2-liter V8, again setting new standards for its rivals to follow. The RS4 has never been renowned for balance or feedback, but no one doubted it's real-world performance (thanks partly to Quattro) as well as the marvelous engines.

Under the pressure of emission reduction, the new car has reverted to twin-turbo V6. Not only it loses 1.3 liters of capacity, it is actually 100 c.c. smaller than the single-turbo 3.0-liter unit serving the lesser S4, strangely. Nevertheless, I suppose you have already known that, because the engine is derived from Porsche and it has been using on the RS5 as well. If you are not familiar with its technical specifications, please read the RS5 report first. In short, it levels with the old V8 in terms of top end power (450 hp), but it offers overwhelming torque at any revs, which peaks at 442 lbft from 1900-5000 rpm. It also helps the RS4 to reduce CO2 emission from 249 to 200 grams per kilometer.

For sure, the turbocharged V6 feels a lot stronger on the road thanks to that tremendous mid-range torque. 0-60 mph can now be reached in 4 seconds flat, half a second quicker than the old car – partly helped by the fact that the new A4 platform cuts 80 kg from its kerb weight. You no longer need to wait for the rev climbs to sky-high rpm to get the power you want. Turbo lag is subtle, while throttle response is reasonably quick. With the optional sport exhaust equipped, the engine produces exciting sound, too, although nowhere near the old V8 singing at 8000-plus rpm. Purists still prefer the V8 for its linear output and sweet-revving manner, but it is undeniable that a torquey engine suits a premium performance estate better. For the same reason, Audi has replaced its in-house 7-speed S tronic twin-clutch gearbox with the popular ZF 8-speed automatic. Its torque converter delivers smoother shifts, but performance seems to suffer no losses.

While it is not the last word for driver engagement, the gaps from its rivals have been narrowed considerably.

Weighing 31 kg less than the V8, the V6 also improves chassis balance. On the other hand, the Avant body of the RS4 (no saloon, as Audi decided RS5 Sportback would be more suitable) shifts more weight towards the rear axle, no wonder the RS4 feels a tad better balanced than the coupe. Both cars employ much the same underpinnings, such as the Quattro system with crown-gear center differential (40:60 torque split in normal situation), the DRC adaptive suspension system that links diagonal suspensions hydraulically to reduce pitch and roll, and the active rear differential. You can opt for active Dynamic steering (better not to), expensive ceramic brakes and lightweight milled alloy wheels. Outside, the RS4 has an angrier front end design, but the strongest implication to its enhanced performance has to be the 30mm wider wheel arches, which are necessary to house its 275/30ZR20 rubbers.

Just like the new RS5, you will find this RS4 has greatly improved ride quality and refinement from its predecessor. Leave it in Comfort mode and it will glide over most roads with ease. It is finally an estate that you will be happy to use every day. Switch to Dynamic mode, it becomes much firmer, but body control also becomes much tighter. You do need this mode to tame its inherent pitch and match the dynamic quality of its rivals, but if you are in mood to attack, the loss of ride comfort matters little. The RS4 still fails to match the Alfa Giulia QF or M3 for balance and agility, or the C63 S for its engaging power slide and mad engine, but it strikes back with superior grip and traction, thanks to 4-wheel drive and those massive tires. Most important, its chassis balances nicely, at least good enough for a performance estate, unlike some earlier RS cars that were prone to terminal understeer. Push it hard enough on a circuit and you can even induce a little bit oversteer, when up to 85 percent torque is directed to the rear wheels by the crown-gear differential. The steering is not very communicative, but again it is improved to acceptable level.

In many aspects the new RS4 is a vast improvement – performance, ride and balance in particular. While it is still not the last word for driver engagement, the gaps from its rivals have been narrowed considerably. I suppose this could have been narrower still if it kept using a naturally aspirated V8. However, this civilized character suits an estate car with Audi badge, more so than the RS5 Coupe.

Verdict: