Mercedes-AMG C63 S E Performance review

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We run the numbers to see if there’s more to the new C63 than half the cylinders

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For the longest time, Mercedes-AMGs were simple beasts to understand. No matter how much clever engineering went into them, they could be reduced to a set of simple emotions. V8 engine goes ‘grrr’; rear tyres go ‘skreee’; driver goes ‘whee!’.

As loud engines become less socially acceptable, emissions targets tighten and owners ask for more daily usability, AMG is changing tack – and in a major way with the new Mercedes-AMG C63 S E Performance. Out goes the tyre-smoking drivetrain with a charismatic V8 and rear-wheel drive, and in comes a four-cylinder plug-in hybrid with four-wheel drive. 

When it first presented the car, AMG said it was about raw performance on the one hand and the convenience of short-distance electric running on the other.

Initial dynamic impressions were not good. Its performance was buried under layers of menus and modes and the package felt rather charmless. It has taken Mercedes some time to bring production cars to the UK, finally giving us a chance to see if longer exposure to this furiously complicated car might unearth misunderstood genius.

Range at a glance

Models Power From
C200 201bhp £46,870
C220d 197bhp £48,320
C300e 308bhp £52,110
C300 255bhp £53,780
C300d 261bhp

£59,120
AMG c43 4Matic 415bhp £69,250
AMG C63 S E Performance 4Matic+ 670bhp £99,280

The Mercedes C-Class range includes petrols, diesels and plug-in hybrids, all available as a saloon and an estate. (Prices above are for the estate.) Most come in one of a number of AMG Line trim levels and all are powered by a four-cylinder engine mated to a nine-speed automatic gearbox. The only four-wheel-drive versions in the UK are the two AMGs.

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DESIGN & STYLING

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mercedes amg c63s review 2024 02 side panning

If nothing else, we can marvel at the engineering in this car.

The C63 uses much the same hybrid system as the Mercedes-AMG GT 63 S E Performance but with a four-cylinder petrol engine instead of the coupé’s V8. It’s termed a P3 system: P stands for parallel hybrid (as opposed to a range-extender, which is a serial hybrid) and 3 indicates that the electric motor is between the gearbox and the differential.

However, rather than sitting literally between the gearbox (AMG’s nine-speeder with a wet start-up clutch instead of a torque converter) and the rear differential, the motor is part of a ‘drive unit’ on the rear axle. It incorporates the 201bhp electric motor, the 6.1kWh high-performance lithium ion battery, the inverters and control units, and a two-speed gearbox. Because this arrangement acts on the rear differential, it also drives the rear propshaft, sending power back through the transfer case and onto all four wheels.

The battery is ‘high performance’ because its chemistry has been developed to repeatedly charge and discharge at great speed rather than for ultimate storage capacity. Hence, it’s only 6.1kWh. (A C300e’s is 25.4kWh.) However, there is a substantial difference between its peak and continuous outputs: 150kW versus 70kW. In other words, after 10 seconds of maximum load, you lose 107bhp. There’s 100kW of regenerative capacity.

Every single cell is actively fluid-cooled, with 14 litres of coolant circulating in total, to keep it at optimum temperature. A lot of hybrid batteries are only air-cooled, or cool the entire pack as a whole, which can cause them to overheat under heavy load.

The idea is that this is not a plug-in hybrid that goes limp when you’ve run the battery dry. You plug it in to get the best fuel economy out of it, but you don’t absolutely have to in order to get the performance.

On the combustion side sits the most powerful four-cylinder engine in any homologated series-production vehicle in the world – and one with a staggering 236bhp per litre. (The Ferrari 296 GTB’s V6 manages 218bhp per litre.)

The 400V electrical architecture plays a part here too, because the huge turbocharger incorporates an electric motor that can spool up the turbine before the exhaust flow gets going, thus reducing the boost threshold and turbo lag. There’s also a belt-driven starter-generator on the same high-voltage circuit that takes care of the ancillaries.

All that fancy tech pushes the kerb weight of this compact estate car to 2217kg on Millbrook’s scales. For comparison, we weighed the BMW M5 CS at 1940kg.

To marshal the weight, AMG has deployed a range of chassis technologies (which add further weight, no doubt). We’ve already mentioned the four-wheel drive, which is fully variable, to the point where front drive can be disconnected in a drift mode.The C63 also has substantially altered suspension compared with a normal C-Class. The steering combines a variable-ratio rack with rear-wheel steering that can turn up to 2.5deg. Different steering knuckles and suspension joints on the spring control arm alter the geometry and actually lengthen the wheelbase by 10mm.

AMG Ride Control adaptive dampers are standard, and for the C63 these are remote-reservoir units with separate, electronically controlled valves for bump and rebound.

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INTERIOR

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mercedes amg c63s review 2024 10 dash

Inside, the C63 is fundamentally a high-spec plug-in hybrid C-Class, but with a few key differences. Perceived quality is generally high thanks to a mix of metal and metal-effect trim and soft leather covering the seats, doors and dashboards. Carbonfibre lower-dash trim is standard and looks sporty but contrasts with the disappointing gloss black plastic centre console and some flimsier fittings.

There’s decent storage space, and despite being very light on physical buttons, Mercedes’ control interface works quickly and intuitively, as we’ve become accustomed to from the MBUX system. Rear cabin space is about typical for what you would expect in a 3 Series Touring rival.

The C63 comes as standard with AMG Performance seats (a Touring package with milder sports seats is a no-cost option), which are very supportive but quite hard and thinly padded and have holes in the backrest. We found them no less comfortable on long distances than most other Mercedes seats and they have the welcome effect of lowering the driving position to a level that is appropriate for a sporting estate.

However, the instruments are set up for the standard C-Class’s higher driving position and can be blocked by the steering wheel if you seek to adjust it to suit the low-set seat. An excellent head-up display is standard, thankfully.

Interior space is compromised by the bulky hybrid drivetrain. A plug-in hybrid C300e Estate already has a smaller boot (360 litres) than a petrol or diesel C-Class (490 litres) but at least it has a flat floor. In the C63, the electronics on top of the rear drive unit intrude into the boot area, reducing capacity further (320 litres) and creating a noticeable step in the floor.

There’s no underfloor storage for the charge cables. An M3 Touring – unhybridised, clearly, but as close a rival as you will find – is not similarly compromised.

ENGINES & PERFORMANCE

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mercedes amg c63s review 2024 23 turbo

Our first drive of the new C63, with its plug-in hybrid four-cylinder engine, left us more than a little underwhelmed.

While the digitally augmented noise it makes is not actively offensive, it’s also in no way a compelling reason to buy the car. Similarly, while the nine-speed automatic gearbox gets the job done, it’s not a main character in the C63’s performance story.

When we attended the launch event, engineers told us that this powertrain will compensate for its lack of charisma with raw performance, so let’s take a look at the numbers. The C63 Estate’s official 0-62mph time of 3.4sec (which it hit exactly in our testing) is 0.2sec quicker than an M3 Touring’s – impressive, but we expected a bit more daylight between the two.

The real story is in the instant, apparently unending and ever-present in-gear thrust. Take a look at the ‘Acceleration in gear’ box on p52, and even if you don’t live and breathe these numbers like we do, you might notice that the box is unusually well filled and doesn’t contain a single figure over 10sec. Even in ninth gear, which isn’t especially short, it simply pulls from low to high revs, laughing at other cars’ limited powerbands.

While the mighty M5 CS is slightly faster from a standing start and pulls harder when the twin-turbo V8 hits its stride, the C63 monsters it from low revs and beats it from 30-70mph in fourth gear. We’ve never performance tested a four-wheel-drive M3 or M4, but the rear-drive M4 we road tested in 2021 isn’t even in the same conversation, and traction is irrelevant when talking about in-gear performance.

Out on real roads, the C63’s huge in-gear pace figures less than one might imagine, though, because to access it you need to press the accelerator past the kickdown switch. First of all, that feels unnatural; and if you’ve left the gearbox in automatic mode, it will indeed kick down, rendering the low-rev thrust moot.

It’s best to engage manual mode. Then the gearbox won’t downshift and you can slingshot out of tight corners when an M3 would still be filling its lungs.

AMG’s promise that the battery will never run out does ring true in road driving. With the powertrain set to at least Sport, the system does a very good job of topping up the battery to half its capacity during times when you’re not demanding full power, so that when you do, the electric motor can give its best.

Electrified Mercedes can suffer from inconsistent brake pedal feel but we did not find this to be the case with the C63. A stopping distance of 43.6m from 70mph is also quite tidy. However, the standard steel-composite brakes did seem to suffer from repeatedly slowing from high speed and felt slightly juddery for a few hundred miles after performance testing. If you plan to take this 2.2-tonne car on track, the carbon-ceramics seem to be a worthwhile investment.

RIDE & HANDLING

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mercedes amg c63s review 2024 24 front cornering

While a 2217kg as-tested kerb weight isn’t as eyebrow-raising today as it would have been before the emergence of large EVs, it is a huge amount for a compact estate car. Those kilograms are also spread throughout the car rather than concentrated down low.

The C63 has the grip and chassis tech to feign some agility but the weight is always there – particularly on turn-in and when negotiating tricky road topography. At the same time, all that complex chassis tech often makes you feel a step further out of touch with the car’s natural handling responses than is ideal.

Mercedes tends to tune a good amount of natural feel into its variable-ratio and four-wheel steering systems but the ultra-quick rack in the C63 might be a step too far. Although it doesn’t feel as hyperactive as 1.9 turns lock to lock implies, finessing your inputs still requires care and there’s not much feedback at normal road speeds.

As you work your way through the AMG Dynamics settings, you won’t find much rear-drive handling balance in the car’s repertoire, until you set the stability control to Sport and engage the Master mode for the four-wheel drive system. So configured, it gains an enjoyable sense of agility, though it never really displays truly pedigree rear-wheel-drive behaviour, preferring to stay neutral at best.

Push through, and rather than becoming subtly throttle-adjustable, it becomes unpredictable; but given the high level of mechanical grip, even this requires quite a bit of commitment to find, and the C63 doesn’t feel very keen to express itself much further.

The suspension is best left in Comfort mode, where it deals with bumpy roads remarkably well up to a certain speed. Beyond that speed on country roads, the dampers start to struggle with the weight, at which point the ride turns choppy. Given the car’s performance potential, those speeds can be achieved startlingly easily, which makes the car’s window of opportunity to really impress you quite small.

Comfort & Isolation

For many, the appeal of a super-estate will be the bravado of a loud engine, but it’s actually quite appealing to sneak away silently from your neighbours on electric power.

The C63 proved one of the more refined cars in its genre at speed as well: 70dBA at 70mph is more than you would expect from a normal C-Class and it’s noisier than an RS4 but it’s considerably quieter than the 73dBA we measured in the M4. An M3 Touring is likely to be the same as the M4, if not noisier, due to the inherent refinement characteristics of estates.

Mercedes-AMG C63 S E Performance news

Report: Mercedes-AMG considers return to V8 for C63 and E63
Report: Mercedes-AMG considers return to V8 for C63 and E63

Despite its performance potential and 20in wheels, the C63 rides well too. It’s firm, of course, even with the suspension in its softest mode, but it’s more relaxed than an M3 and still has that ‘expensive damper’ feel, where it’s perfectly controlled and nicely rounds off sharp intrusions.

The AMG Performance seats aren’t quite as hardcore as BMW M’s carbon-backed equivalents, but they still provide all the lateral support you could need and are easier to get in and out of. But for all that, they are quite firmly padded.

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MPG & RUNNING COSTS

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mercedes amg c63s review 2024 01 front tracking

You might expect all the tech in the C63 to spectacularly inflate its price, and while starting prices are higher than for the M3, at £97,530 for the saloon and £99,280 for the estate, it follows the same modus operandi of the mainstream Mercedes range in that it comes with a lot of standard equipment.

Once you option an M3 Touring to the same level, there’s not much in it. Whatever the case, though, it’s an enormous amount of money for a four-cylinder C-Class.

Surely it will be economical, right? If you do many sub-seven-mile trips, it might be, but if you don’t charge it fastidiously and do make regular use of the power, you will struggle to beat 30mpg – only slightly better than what you might get in the M3.

If you were hoping this plug-in hybrid would be one to sneak past the company car fleet manager, you’ll be disappointed: the C63 emits too much CO2 and its EV range is too short to qualify for lower benefit-in-kind tax.

VERDICT

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mercedes amg c63s review 2024 27 static

Mercedes-AMG is not alone in switching to a plug-in hybrid drivetrain. The Audi RS4’s successor will have plug-in power, as will the next generation of the BMW M3. Those two will retain six-cylinder engines, but AMG deserves some credit for going first, and avoiding some of the pitfalls of plug-in power.

We like that the C63 can be plugged in to give a few miles of electric running – but that it doesn’t need to be to perform properly. It manages to extract a performance benefit from its electrification, even if it doesn’t count for all that much on the road.

However, despite using a relatively small battery, the C63 can’t escape its weight or complexity. As a result, you enjoy its performance and handling on its terms rather than your own. And while the engine is quite characterful for a modern four-cylinder, it’s no match for rivals’ sixes, or the spectacular V8 that came before.

Neither the powertrain nor the handling imparts much of a sense of occasion and, in spite of a number of rational arguments in favour of the hybrid C63, that means it ultimately disappoints as a driver’s car and therefore as a super-estate.

Illya Verpraet

Illya Verpraet Road Tester Autocar
Title: Road Tester

As part of Autocar’s road test team, Illya drives everything from superminis to supercars, and writes reviews, comparison tests, as well as the odd feature and news story. 

Much of his time is spent wrangling the data logger and wielding the tape measure to gather the data for Autocar’s eight-page road tests, which are the most rigorous in the business thanks to independent performance, fuel consumption and noise figures.