Mercedes-Benz is hoping prospective buyers will have faith that the mad scientists over at its AMG performance division haven’t abandoned their core values of creating high-performance premium machines.
That’s in spite of a quantum shift in execution that could be enough to cause a collective gasp amongst driving enthusiasts. That’s what you get with the 2025 Mercedes-AMG GLC 63, a performance SUV that bids adieu to one of its finest features this time around. In its place is a piece of engineering backed up by big claims and Formula One-inspired technology; but that doesn’t necessarily mean this is the same animal as before.
The Elephant in the Engine Bay
Like the Mercedes C-Class sedan with the same AMG treatment, this taller, more practical GLC 63 has swapped its thunderous V8 in favour of a four-cylinder under the hood. That’s right: the previous four litres of displacement and a pair of turbochargers backing it up has been whittled down to half that on both counts.
Time to gather the pitchforks and torches and head to Affalterbach for blood, right? Not so fast. This 2.0L turbo isn’t your run-of-the-mill commuter engine – it’s the world’s most powerful production four-cylinder, generating 469 hp and 402 lb-ft of torque. That’s a heck of a lot of fizz from something displacing the same volume as a big bottle of pop.
But this hand-built mill also benefits from a bunch of key learning that Mercedes collected while building Formula One engines. For instance, the GLC 63’s power plant is the first production engine to fit a slim electric motor between the turbo’s intake compressor wheel and the exhaust-side turbine. Traditionally, a turbocharger is only useful once the engine is blowing enough hot exhaust gases to spin it up, but this electrically-actuated unit is already spinning, meaning there’s zero turbo lag. What’s more, when lifting off the throttle, the electric motor keeps the turbo spinning, so there’s no waiting for the turbo to spool up again when you want to rocket out of a corner.
An Electric Ace in the Hole
The tiny engine on its own is formidable, but the V8 of old bellowed out 502 hp, so yet more race-derived technology was added. With an electric motor at the rear axle along with its own two-speed transmission and an electrically controlled limited-slip differential, AMG has created a very complex but highly effective power delivery system. The 400-volt battery borrows F1 technology with its non-conductive liquid cooling that flows around all 560 cells. This is important because batteries that quickly or frequently charge or discharge tend to overheat, which results in noticeable power degradation. Not so here, with the battery kept to a consistent temperature and 107 hp always chomping at the bit, and as much as 201 hp available for bursts of up to 10 seconds at a time.
Together, the engine and electric motor generate 671 hp and a whopping 752 lb-ft of torque. That output is enough to shove this little SUV to 100 km/h in just 3.5 seconds – roughly the same as the old GLC 63 S could muster. And while the curb weight of the new GLC 63 hasn’t been revealed, it’s safe to assume it’s somewhat portlier than before. Such is the cost of electrification and those heavy batteries.
Fast and Fun
A driver with enough nerve (and pavement) can see the GLC 63 storm all the way to an electronically limited top speed of 275 km/h. And while this test didn’t offer the opportunity to confirm that figure, winding ribbons of road draped over mountains tested your humble author’s faith in this AMG-tuned SUV – and it passed with flying colours through blind curves, narrow pavement, and unguarded cliff edges.
All the technology delivered as promised, with snappy, near-instant throttle response. There was never a moment where the little engine had to catch its breath before compressing the driver’s torso into the seatback. Special care was taken by the engineers to calibrate the throttle response to work smoothly with this wildly responsive drivetrain. There’s never any snatchy on-off action, but rather a beautifully linear doling out of forward momentum.
Equally remarkable is the duality of the GLC 63’s personality, where it’s just as happy to report for performance duty as it is the picture of subtle, serene cruising, without much indication of the wickedness available at the prod of the throttle. In fact, during a leisurely stretch of driving, the electric motor assisted the small engine enough to sip fuel at an indicated average of 6.6 L/100 km for about 40 to 50 km (even then, it only climbed into the mid-8s after 150 km or so of mixed highway and twisty backroad driving).
Testing on beautifully smooth pavement proved tough to get a true read on the GLC 63’s ride quality. Even so, the occasional bump was largely extinguished by the standard adaptive suspension. The ride is certainly on the firm side, but even in the aggressive pro drive mode, it’s not harsh.
Meanwhile, active roll stabilization constantly works to manage body movement, while the speed-sensitive steering also utilizes rear-axle steering to offer both swiftness and stability in response to driver inputs. While the system feels more impressive still when applied to larger vehicles, this compact SUV offers excellent controllability and precision when hurried from one hairpin to the next. At lower speeds, the rear wheels turn up to 2.5 degrees opposite the fronts for manoeuvrability, while over 100 km/h, all four wheels turn in the same direction up to 0.7 degrees for increased stability.
A Different Kind of Animal
In practice, all the technology works brilliantly to enable an incredibly quick and capable sport utility vehicle. With room for five on board, the GLC 63 makes a great year-round daily driver that just happens to be adept at awesome high-speed achievements. But then the previous V8-powered did the same with a highly addictive roar, not to mention a fair amount of wildness. That’s simply no longer the case, with all the technology – and the decidedly unmelodic engine – constantly serving as a reminder that this is a very well-engineered machine, but not a wild animal.
As with the previous generation, the styling is strong and handsome, but not garish, just as it ought to be. Most observers probably won’t notice the specific AMG grille with its vertical slats, or the deeper air dam; same with the side sills and aggressive bumper treatment around back. But together – and along with a few beautiful wheel options – it’s a decidedly sportier-looking rendition of the GLC-Class.
The inside is dolled-up with high-quality materials and finishes, and the front seats in particular balance the aggressive bolstering with all-day comfort better than expected. In the back, the rear seats offer the same spaciousness and comfort found in other contemporary GLC-Class models.
The digital gauge display can be configured in a number of different ways, while the primary infotainment display includes Mercedes’s latest interface that’s fast, responsive, and easy to work with. Plus, in the GLC 63 S, it includes a wealth of track-related performance displays including acceleration times, steering angle, and track data logger.
Final Thoughts
In every objective performance metric, the 2025 Mercedes-AMG GLC 63 is unquestionably superior to the model it replaces. Beyond that, when not driven in anger, it does double duty as a smooth, luxurious cruiser, plus it’s more efficient, and a safer, easier-to-handle SUV, too. It remains a very attractive and well-crafted machine, but as over-achieving as its little electrified powertrain is, it’s led to the loss of some of the wild, animalistic character of before.
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