Mercedes A-class (W176)

	Mercedes A-class (W176)
	Debut: 2012 Maker: Mercedes-Benz Predecessor: A-class (W169)

Published on 21 Jul 2012

The 1997 A-class was a breakthrough to Mercedes-Benz. Not only it was the company's first front-wheel drive small car, it also introduced a revolutionary "sandwich" structure which enabled a spacious interior out of a very compact body shell. Unfortunately, like many innovative ideas, the sandwich structure fell victim to its uniqueness. It demanded bespoke engines, gearboxes, suspensions and almost everything so that component sharing with other models was virtually impossible. As a result, the first two generations of A-class were more costly to build than conventional family hatches thus they were hardly profitable. For the third generation, Mercedes finally ditches the sandwich structure and switches to conventional FF architecture. Hopefully this will allow more models to be built upon it, such as B-class, CLC, GLC and even an Infiniti hatchback through the joint-venture agreement with Renault-Nissan group. Much larger economy of scale should drive down the cost basis.

In terms of mechanical layout, the new A-class is no different to a Volkswagen Golf or Audi A3. Its four-cylinder engine is mounted transversely above the front axle and drives the front wheels (4matic will be available later). The front and rear suspensions are MacPherson struts and multi-link setup respectively. Power steering is provided by a rack-mounted dual-pinion electric system. In other words, thoroughly modern but nothing unconventional. However, having set its main target at BMW 1-Series, the Mercedes design team deliberately shaped it like a rear-wheel-drive sporty hatchback. This is implemented with unusually long bonnet and front overhang which deliver a false impression of longitudinal engine. Thanks to the long bonnet, the glass house looks more rearward than it actually is, hence a cab-rearward profile like the 1-Series. Moreover, the Mercedes design is more successful aesthetically, looking both sportier and more stylish than the underachieving BMW. Without knowing their contents, you might think the A-class was the sportier one.

That is not the real case, of course. Although Mercedes worked hard to persuade keen drivers with its optional AMG suspensions (harder and lower than the standard setup), a very direct variable-rate steering and wheels/tires combination as aggressive as 235/40ZR18, the A-class is sporty up to a point. It offers excellent grip, good body control, accurate steering and good resistance to understeer in most circumstances, but it never stops feeling nose-led, lacking the sense of agility you can find in BMW 125i M Sport. Moreover, with these aggressive options the ride quality does suffers from a harshness you won't expect on a Mercedes.

That means the regular suspension, wheels and tires are better bet. With these the A-class is more enjoyable for everyday driving. Its ride is pretty absorbent and quiet, although the latter is partly offset by the intrusive wind noise from the A-pillars. Even though it does not match 1-Series for handling, it is slightly sportier and more engaging than the new Audi A3. Compare with the outgoing A-class, its handling is a day-and-night difference, of course. The difference is contributed by not only its 24 mm lower center of gravity but also the fact that you sit 174 mm lower in the cabin, i.e. right on the floorpan rather than the second layer of sandwich. The new car's generous use of high/ultra-high-strength steel (67 percent of all) and aluminum components (bonnet, rear wheel carriers and spring links) also help.

Apart from handling, performance and economy are also vastly improved from the old car. While the latter employed some outdated SOHC engines, the new car is offered with a new range of M270-series four-cylinder petrol engines. They are really state of the art, with all-alloy construction, DOHC 16-valves, intake variable cam phasing, on-demand lubrication/cooling, automatic stop-start, turbocharging, multi-spark ignition and sophisticated piezo direct injection – the latter enables up to 4 injections per combustion, resulting in Euro-6-compliant emission and reduced consumption. The turbocharging employs scavenging effect to cut turbo lag (by overlapping intake and exhaust valve opening, it lets fresh air to rush into exhaust manifold and spool up the turbine). The entry-level engine displaces 1595 cc and has two states of tune – A180 with 122 hp / 147 lbft and A200 with 156 hp / 184 lbft. Both achieve peak torque from a respectable 1250 to 4000 rpm. The 1.6-liter unit also introduces Mercedes' new Camtronic variable valve lift to reduce pumping loss at part load. This results in another 4 percent improvement in combined consumption. Both engines emit less than 130 grams of CO2 per km.

Another member of M270 displaces 1991 cc and serves A250. It does not have Camtronic, but it adds twin-balancer shafts at the bottom of the block to suppress its extra vibration. The engine looks good on paper, with 211 horsepower and a Golf GTI-beating 258 lbft of torque from 1200-4000 rpm. Unfortunately, its power delivery is a bit diesel-like, i.e. gusty low down but lacks sparkles at the top end – it redlines at only 6200 rpm, versus 7000 rpm on Golf GTI. The 7G-DCT dual-clutch gearbox it partners is also nowhere as responsive as Volkswagen's DSG. Consequently, the A250 does not feel as thrilling as its 149 mph top speed or 0-60 mph figure of 6.3 seconds suggested. It is a fast premium hatch rather than a true hot hatch.

On the diesel side, Mercedes OM651 series turbo diesel engines have 3 variants: 2.1-liter 170 hp for A220 CDI, 1.8-liter 136 hp for A200 CDI and 1.8-liter 109 hp for A180 CDI with 7G-DCT. Worth noting is that the A180 CDI equipped with manual gearbox is served with Renault's 109 hp 1.5dCi engine instead, despite of a new codename OM607. As we already know, the Renault engine is a superb one, being frugal, refined and energetic. No wonder Mercedes is pleased to employ it. That said, A200 CDI is the pick of the bunch with all things considered.

All A-class models come with eye-popping fuel economy and emission numbers. Apart from more efficient engines, the class-leading aerodynamics also helps a lot. Regular models have a Cd of 0.27, thanks to adjustable radiator grille shutter, underbody cladding and finlets located next to the rear window. The sleekest A180 BlueEfficiency Edition even achieves 0.26 with the help of partially sealled grille and reduced ride height. Other contributors to improved economy include taller gearing and a lazy Eco mode of the 7G-DCT gearbox.

The interior of new A-class is not as spacious as its predecessor's, of course. In fact, for a front-wheel-drive hatchback running a generous 2700 mm wheelbase, the space it offers is disappointing. It has barely enough room for four six-footers. Visibility and sense of airiness are seriously hampered by the shallow glass, prominent C-pillars and tapered side windows. Fortunately, the driving position is good and the front seats are comfortable. The dashboard, console and door panels are not exactly the same as that of the B-class, but they obviously share a lot of components. The whole thing looks stylish and high-quality, but touch it and you will find some switches feel cheap and some storage compartment lids feel filmsy, so it fails to match Audi A3, Volvo V40 and BMW 1-Series for sense of quality. The 340-liter boot is on the small side, and its aperture is seriously narrowed by the fixed taillights. Sadly, what used to be the traditional strengths of A-class become its weaknesses.

Compare with the old A-class, the new car is unquestionably more rounded, especially in performance and handling. However, in the process of normalization it also loses its own character. Compare with its rivals, it is not particularly good to drive. Neither is it particularly refined, comfortable, spacious or well built. Save a good look, there is virtually nothing let it stand out of the crowd. Nevertheless, to many people the combination of stylish look and a three-pointed star badge is already enough to seal a deal. Whether it will be sold at higher volume than its predecessors remains to be seen, but the common platform strategy should bring a brighter future to the A-class.

Verdict:

Published on 22 Jul 2013

A45 AMG

As you might have observed, AMG has overtaken BMW's M division in recent years. Its CLK63 Black series, CLK DTM, C63, E63 and C63 Coupe Black series all earned the highest regards from car enthusiasts. However, can it play the same magic if it leaves the traditional formula of V8 engine and FR chassis behind? That will be interesting to see. So far AMG's service covers only the FR platforms of Mercedes. As the front-wheel-drive MFA platform is getting more and more important to Stuttgart, AMG has to expand to the Mercedes small cars. The first act is A45 AMG.

Don't be fooled by its name, the A45 is powered by not a 4.5-liter V8 but an engine with half the cylinder count and less than half the capacity. Codenamed M133, this turbocharged straight-four displaces only 1991 cc, i.e. the same as A250. This might raise many eyebrows, especially when Audi RS3 and BMW M135i employ a 2.5-liter five-cylinder turbo and a 3-liter straight-six turbo respectively. However, the M133 answers your doubt with some jaw-dropping numbers: despite of its small capacity, its maximum output is 360 horsepower at 6000 rpm, whereas peak torque is equally impressive at 332 lbft, delivering from 2250 to 5000 rpm. That means its specific output is 180.8 hp, a new record for production engines! This is not only the most powerful 2-liter engine in the world but also the most powerful four-cylinder engine of all (remark: forget Mitsubishi Evo FQ400 or the like as they were not type approved). It eclipses its Audi and BMW rivals by 20 hp and 40 hp respectively, and trumps the same-capacity Renault Megane RS265 by nearly 100 horsepower! Judging by stop watch, it also beats them convincingly with a 0-60 mph time of 4.4 seconds, although all cars are capped by 155 mph. A 4.4-seconds hot hatch! Can you believe? How can AMG achieve this?

The M133 is derived from the A250 engine, but it is heavily reworked. It gets a stronger sand-cast aluminum block, forged steel crankshaft and forged pistons. A large twin-scroll turbo is employed to provide boost pressure up to 1.8 bar, again an unheard figure for production engines. To deal with the tremendous heat resulted from the ultra-high boost pressure, AMG developed a 2-stage intercooler system which has an additional cooler in the left wheel arch. Meanwhile, cooling to the engine water circuit and transmission lubrication oil are both handled by a heavy-duty cooling system integrated with the transmission. Apart from hugely powerful, the engine keeps the fuel economy advantage of four-cylinder motors, returning 41 mpg on European combined cycle. This is partly thanks to automatic stop-start and spray-guided direct injection.

There is no way a front-wheel-drive chassis could tame 360 horses, therefore AMG fitted it with mandatory 4matic system. It employs a rear-mounted Haldex electrohydraulic multi-plate clutch (like VW 4motion or Audi's Quattro on transverse-engine applications) to engage the rear axle when the front end slips. This mean the A45 is primarily FWD in normal driving conditions, unlike the full-time 4WD on Evo or Impreza. The A-class' 7-speed twin-clutch gearbox is employed but strengthened and reprogrammed by AMG. It features 3 modes (Controlled Efficiency, Sport and Manual), in addition to double-declutching and Race Start function. The speed-sensitive dual-pinion electric power steering gets faster but fixed ratio (14.5:1). The reworked suspension gets sturdier components and sportier tuning but the dampers are left passive. Rear subframe is now mounted rigidly to the monocoque body to sharpen chassis response. 18-inch wheels are shod with 235/40ZR18 tires. Running within them are upgraded brakes, with ventilated and perforated discs measuring 350 mm front and 330 mm rear. Finally, a 3-stage ESP (On, Sport or Off) completes the package. Everything looks classy.

You might find the AMG version doesn't look remarkably different from lesser A-class with AMG Sport kits. Considering how striking the latter looks, only fools would ask for more differentiation. It has to be rated as the most stylish hot hatch together with Opel Astra OPC and Renault Megane RS, so it has a strong advantage over the ugly M135i and dull Audi S3.

On the flip side, the AMG is also the most expensive hot hatch on the market. Priced at £38,000 before options, it makes the £30,000 M135i looks great value and the £22,000 Ford Focus ST like bargain of the century. But then the AMG does feel more special and provides you with classier ingredients. After all, this is an AMG.

Inside, the AMG has an excellent pair of Recaro bucket seats, and you can opt for some very tasteful carbon-fiber trims on the dash and door inserts. As in lesser A-class, the driving position and ergonomics are good. Rearward visibility less so, while some plastics and switches look cheap and disgraceful for a car so pricey.

On the Road

Once getting it to the road, you will quickly forget about the cheap plastics. This car is really fast! Megane RS265 and Astra OPC are a league or two slower. Even the big-engined M135i fails to keep up with it, no matter on straights or on mountain roads. The AMG uses its superior power and 4-wheel traction to destroy its oppositions. Forget the claims of 0-60 mph in 4.4 seconds, I won't be surprised if road test results fall between 4.0 and 4.2 seconds, and 0-100 mph should be accomplished in about 10 seconds, believe or not.

Inevitably, the high-boost 2-liter engine is not as responsive at low rev as the BMW straight-six, but its twin-scroll turbo is not particularly laggy either. Tractability at low rev is okay, but it starts working like a performance engine from 2000 rpm and gets a second lease of life from 5000 rpm. From there to the 6500 rpm redline it really goes mad! This top-end rush makes a big difference to the driving experience as it tempts you to push harder and harder just for the sake of fun. The higher the rev, the more responsive and the smoother the engine becomes, which is really addictive. This sensation is also supported with a sporty exhaust note. Like AMG's 5.5-liter twin-turbo V8, it releases pops and crackles on the overrun to remind you that turbocharged engine is not necessarily boring to listen to.

The 7-speed twin-clutch gearbox is slightly less satisfying. It is not as fast as DSG / S-Tronic and sometimes it may be reluctant to downshift. However, it is already an improvement from the standard unit on A-class. For most of the time it doesn't spoil the driving experience.

Although the driving experience is dominated by the engine, the chassis is not mediocre either. We are not convinced with how the regular A-class handle and ride, but the AMG version is a lot more satisfying. It still rides very hard compared with most hot hatches, but the damping is very well developed so that it resists pitch and roll brilliantly, keeping the car composed on whatever surfaces. It feels keen and alert. Despite of the similar 4WD design, it resists understeer much better than the Quattro-equipped Audis, proving that chassis tuning is even more important than mechanical layout. No, it cannot play power slide like the rear-drive M135i or 4-wheel drift like Evo or STi, neither can it match Megane RS265 for mid-corner adjustability, but it still steers keenly and accurately while offering remarkable traction and grip. The 4matic allows you to exploit its tremendous power without fear. As a result, you can push the A45 much harder than its rivals on challenging roads. This is more than enough to offset its less playful back end.

More interesting is, the chassis feels better the faster it goes. The ride improves with speed. The steering, which isn't fully transparent at lower speeds, weighs up and becomes reassuring. The massive brakes give you full confidence to push the car as hard as you can. This is a car born to be driven fast. In other words, a real driver's car. It replaces Evo X to be the fastest A-to-B car today. It also trumps M135i and RS265 for driving excitement. A new hot hatch King is born.

Verdict:

Published on 15 Sep 2015

A45 AMG 381 hp

A45 AMG has never been short of power. In fact, with 360 horsepower on tap it is still by far the most powerful hot hatch in the 2.0-liter class as of today. However, recently Audi RS3 has stolen the headline with a larger, 2.5-liter 5-cylinder engine, which offers an extra 7 horsepower over the AMG and beats the latter by 0.3 seconds in the race of 0-60 mph. As the AMG is already beaten by Renault Megane RS and Volkswagen Golf R for handling and driver engagement, it needs to win the game of numbers. That’s why we get the 381 hp version just 2 years after the original car.

The updated A45 AMG – well, it should be called Mercedes-AMG A45 now under the new nomenclature – is introduced together with the facelifted A-class range. As usual, we’ll skip the exterior changes because your eyes are just as good as mine. Let’s concentrate on the stuffs that really improve performance. First is the enhanced aero kits that come as option. These include the small winglets added to the sides of front bumper, the more prominent front splitter and the eye-catching rear spoiler added to the top of tailgate. At high speed on Autobahn you can certainly feel the improved straight line stability they brought.

Although the M133 engine is already at very high state of tune, AMG still finds extra grunt by revising its valve timing, intake, exhaust, combustion etc. There are no dramatic changes, nor the turbo boost pressure is altered, but these small modifications contribute to an extra 21 horsepower and 18 pound-foot of torque. The higher peak power and torque are delivered at the same revs as before, so you get more grunt without altering the characteristics of the engine. There might be a little bit more keenness at low rev, which is probably contributed by the 7G-DCT’s shorter, closer ratios from 3rd to 7th, but overall the M133 is still renowned for an explosive mid-range punch. Yes, what a punch! Now it will do 0-60 mph in just 4 seconds flat! De-restricted, it could easily trump Honda Civic Type R with 170 mph top speed. This could be the first hot hatch qualified for the status of supercars.

As before, the most memorable moment of the A45 is when the crazy engine working on full song. Its 4-wheel-drive traction allows you to exploit the tremendous punch very effectively. This is improved further by the optional Dynamic+ package of this update, which adds a mechanical LSD to the front axle and a 2-stage selectable adaptive damping system. The former makes cornering at tight corners a little swifter, while the latter softens the ride a bit in comfort mode. No, they don’t transform the car’s behavior. You might complain that the A45 still exhibits too much understeer at the limit compared with the best in class, or it doesn’t oversteer on throttle like Megane RS. The ride is still on the firm side compared with many rivals. But the AMG has its own strengths – superior straight line speed, endless traction and grip, good looks and classy interior. Its closest rival is Audi RS3, and it beats that car obviously. That is perhaps the most important mission of this update.

Verdict: