Mercedes Built A 637-hp V8 Rival To The M4 CSL, But Only 30 Exist
by Horatiu Boeriu · BMWBLOGMercedes-AMG has pulled the all-wheel drive and the rear seats out of a CLE 53, replaced its inline-six with a 637-hp twin-turbo V8, and will build 30 of the result. The CLE 646 Spezialanfertigung (roughly, “special build”) was sold out before anyone outside Affalterbach saw it.
BMW fans will recognize the recipe. Rear-wheel drive, no back seat, carbon where there used to be steel, and a chassis set up for the track before the road. That describes the G82 M4 CSL, the car that has held the Nürburgring Nordschleife’s mid-size record since 2022.
A V8, Rear-Drive CLE With The Comfort Stripped Out
The engine is AMG’s M177 Evo 4.0-liter twin-turbo V8 with a flat-plane crankshaft. It makes 637 hp (475 kW, or the 646 PS that gives the car its name) and 850 Nm (627 lb-ft) between 2,500 and 4,500 rpm. Power goes through AMG’s nine-speed SPEEDSHIFT TCT 9G automatic to the rear wheels only, via an electronically controlled limited-slip differential. Mercedes quotes 0-100 km/h (0-62 mph) in 3.9 seconds, 0-200 km/h (124 mph) in 11.4 seconds, and a top speed of 310 km/h (193 mph).
Mercedes says the car weighs around 170 kg (375 pounds) less than the CLE 53 it’s built from. Carbon fiber replaces the front fenders, front apron, side sills, hood, roof, rear apron, and trunk lid, and the rear wing is carbon too. The rear window and rear side windows are polycarbonate, and the 12-volt battery is a lighter unit. The rear seats, sound insulation, and even the parking sensors are gone. In their place are a roll-over bar and racing buckets, with six-point harnesses available as an option.
The body is 60 mm (2.4 inches) wider front and rear and sits 22 mm lower at the front axle and 16 mm lower at the rear. Mercedes developed the steel coilovers with KW, and the dampers are four-way adjustable. The forged 20-inch wheels wear 305/30 tires up front and 335/30 at the rear, based on technology from the AMG One. Carbon-ceramic brakes use 420-mm (16.5-inch) front discs with six-piston calipers.
The aero is where the CLE gets serious. The front diffuser bolts into either a Street or a Race position, and the center section of the rear wing adjusts manually to balance it. Mercedes claims well over 250 kg (551 pounds) of downforce at top speed. The drag coefficient goes from 0.402 in Street trim to 0.417 in Race.
AMG boss Stefan Weckbach says the project started with a small group of engineers building a prototype on their own initiative, and that “highly rational engineers dreamed of a highly irrational car.” A 30-car run that sold out before its debut is about as rational as AMG business cases get, but we take the point.
Mercedes hasn’t given a price. The comparisons on offer aren’t reassuring: the first Mythos car, the PureSpeed roadster, reportedly started near 922,000 euros, and rumors around the CLE 646 range from $500,000 to $800,000. Whatever the real number, this is a seven-figure car, and that matters for the record-chasing angle below.
How The Numbers Line Up Against The M4 CSL
- Output: 637 hp (475 kW) for the CLE 646, 543 hp (405 kW) for the M4 CSL
- Torque: 850 Nm (627 lb-ft) vs. 650 Nm (479 lb-ft)
- 0-100 km/h: 3.9 seconds vs. 3.7 seconds
- DIN curb weight: 1,895 kg (4,178 pounds) vs. 1,625 kg (3,583 pounds)
- Production: 30 vs. 1,000
The BMW gets to 100 km/h two tenths quicker with 94 fewer horsepower, and the 270 kg gap explains it. BMW’s carbon roof, hood, and trunk lid and the rest of the CSL’s diet got it down to a weight the Mercedes can’t approach, even after AMG’s own diet. Work out the power-to-weight ratios and the two cars land almost on top of each other: 2.97 kg per hp for the CLE 646, 2.99 kg per hp for the CSL. All that extra V8 does is cancel out the extra mass.
So a lap-time fight wouldn’t be settled in the engine bay. The Mercedes would lean on its wider track, its AMG One-derived tires, and an aero package with a dedicated Race setting. Working against it are a 56/44 front-to-rear weight distribution and a pair of rear tires that have to handle 850 Nm on their own.
Is The M4 CSL The Real Competitor?
The car that will actually line up against the M4 CSL isn’t this one. AMG has a series-production CLE 63 in development, reportedly with the same 646-hp V8, and that’s the version most buyers will be able to order. It won’t be gutted or wide-bodied, so it won’t chase the CSL’s lap time, but it’s the fair fight: a V8 coupe you can buy against BMW’s inline-six special. The Spezialanfertigung is the halo above it, a demonstration of how far the CLE will stretch.
None of that makes the Mercedes less interesting to us. In an era of the four-cylinder plug-in hybrid C 63, AMG going back to a V8, rear-wheel drive, and a gutted cabin is worth celebrating. It also shows how well BMW M judged the CSL.
[Photos: Mercedes-Benz]
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