Euro-Spec Muscle: Mercedes-Benz CLK63 Black Series
Owning a highly modified car in California is a hassle due to the state's strict smog laws, so David Huang sold off his turbocharged, engine swapped show cars and built a 2008 Mercedes-Benz CLK63 Black Series with an OEM+ theme.
Now, before you lay into the fact that this 2008 Mercedes-Benz CLK63 Black Series doesn’t look like it has any aftermarket parts or other work done to it, you must understand where David Huang comes from. He’s owned three award-winning show cars that he drove on the street–most notably his "Lexus IS 1000," a 2005 Lexus IS 300 with a 1000-horsepower 2JZGTE engine that has been in numerous magazines and won SEMA's Showcase Award in 2009. He knows the life of highly modified street car ownership in the restrictive state of California. It’s neither cheap nor easy.
“I wanted something rare that holds value while I can enjoy the car just way it is,” David explained, “which is hard to find one in stock-form; I’ve had no prior ownership of any Mercedes Benz, but the Black Series checked off everything on my list.” If you’re a Mercedes fan, you know exactly what he’s talking about. However, let’s assume you’re not. What’s so special about the CLK63 Black Series?
For starters, there are only 500 in the world made between 2007 to 2009, and the United States got 350 of them. Not Canada, not Mexico, just the United States although many of them were (or eventually were) exported out of the country as a whole or in parts in some cases. They, as the name states, came in two different shades of black as well as 149 in Silver, 40 in White, 10 in Red, and 1 in a Matte Silver. That Matte Silver would go on to be a "designo" color after that.
It gets better than color as these cars didn’t come with an air suspension system. Instead, it uses adjustable AMG coilovers with piggyback reservoirs. 19-inch wheels with Pirelli P-Zero Corsa tires, larger air intakes, rear seat delete, wider fenders made of carbon fiber, an AMG SpeedShift 7G-Tronic transmission; it was essentially a street-legal track car with some creature comforts without the annoyance of a cage.
The heart of this car or many would argue, the soul, of the CLK63 Black Series, is the M156 6.2-liter V8. It felt like a punch to the chest when you hit the throttle as it rocketed off with 465 lb-ft of torque at 5250-RPM and 500-horsepower came at you by 6800-RPM. There was no other engine like it from Mercedes until the M159 came out for the SLS AMG, but the M156 made its power with 102.2mm (4.02-inch) bores and a stroke of 94.6mm (3.72-inches) at 11.3:1 compression.
So, unlike most AMG engines, this one was made to be naturally aspirated; no supercharger above the intake or turbochargers hanging from the exhaust manifolds. That means that exhaust tone isn’t muffled nor is a whine added to it. Honestly, if there is something Mercedes gets that's American, it’s big displacement with a throaty noise that will give GM LS-guys and Ford Coyote-lovers a run for their money.
The best part is the fact that the menacing V8 noise comes out of polished AMG quad exhaust tips. A carbon fiber diffuser underneath the bumper surrounds those quad tips, with a transmission cooler sitting behind the vents.
Of course, like many European models, there were some details left out of the American CLK63 Black cars. Even though we got the lion’s share of the 500 produced worldwide, we didn’t receive all of the features that Europe did.
That’s where David began to improve his Black Series after purchasing it in 2013. One of the surprising things left out was the fixed back AMG-Recaro bucket seats, but you’ll find that in this car.
Behind the Recaro buckets are a set of stylish looking rear seat deletes.
What David did was turn this into a Euro-Spec version and made it a bit OEM+, (the trend of improving a car with factory-made upgrade parts not offered typically here in the US or sometimes on the model you’re working with). You’d think getting OEM parts would be easy; they aren’t custom made, and you should be able to get them from German dealers. Right? “Sourcing the parts was just as much of a journey as sourcing the car,” David recounted, “many contacts fell apart, as it was challenging to source German OEM parts without a donor Vehicle Identification Number from an actual Euro-spec CLK63 Black Series to order the parts for.”
Dealer parts counters aren’t there to research your modifications since you don’t have a VIN and you don’t know a part number. Their job is to make money for the dealership and do it as quickly as possible. Even the German-based dealers wouldn’t help when David took a trip to Europe to take delivery of another car he purchased. However, he eventually found a source that could take time and help him get the parts. Even then, “dealing with the import and US Customs was another a big hassle,” he continued, “but after taking some time, everything landed perfectly.”
Many of the changes ultimately make this CLK63 Black Series look different than the ones you see here in the US. Rather staggeringly so, if we can be honest here. There are small changes, like the front bumper corners. The US version has amber reflectors with bulbs while the European version is a paint-matched cover.
David removed the US market rear trunk door, and swapped it for the European rear trunk that's designed to accept the wide, narrow Euro-style plates.
Inside, the fixed-back Recaro-AMG seats replace the reclining leather versions, but you’ll also see that the center console was replaced.
The US version has cup holders while the driving-focused European version has none. (People shouldn't have drinks in a car like this anyway.) The glove box and door trims have their US version silver versions replaced with black ones that were originally in the Euro-versions.
The door handles are aluminum, whereas the US versions were leather wrapped. The factory US spec door cards were replaced in favor of European market AMG factory carbon fiber door panels meaning that the side curtain airbags were removed.
Finally, the steering wheel is the Euro-optional Alcantara-wrapped wheel made by HWA. This wheel was one of only three parts that were optional on the European CLK63 Black Series. Though David hasn’t torn the engine down to create a 1000-horsepower beast, there are some performance bits; both Euro OEM and aftermarket.
The intake pipes for the M156 are different between the US and Euro versions, too. The US version feeds air into the pipes at the bottom of the grille, the Euro feeds it at the top. The air filter boxes are also unique to one another; the outside shape is still the same, but the inner housing isn't and uses a different air filter more common for the rest of the world.
A Weistec Oil Catch Can captures the excess oil as the positive crankcase ventilation relives the engine. The oil catch can helps to ensure that those oil vapors don’t layer inside the intake piping and manifold.
To increase the reliability of the M156 engine, a set of Weistec Titanium Head Bolts secure the heads better than the factory set. Head bolts are a known problem of owners of this engine. They tend to fail, which leads to engine failure as it allows the head to lift and engine coolant and oil fill the cylinder. If you’re constantly filling your coolant and you don’t find a leak outside of the engine, you are most likely looking at a head bolt failure. Unfortunately, neither are an inexpensive endeavor but replacing head bolts are cheaper than replacing the engine. It’s also not a process for the faint of heart or those lacking a proper set of tools. If you’ve never changed heads before, you are probably best allowing a Mercedes-Benz mechanic to tackle this project.
Finally, the Engine Control Unit (ECU) and Transmission Control Unit (TCU), which is integrated into the valve body of the 7G-Tronic 722.9, were tuned by Weistec. This wasn’t a standard flash that was “off-the-shelf,” but a custom flash performed on a dynamometer. The tune for the engine was to help recover some lost power from age. The transmission, however, was tuned for smoother shifts and a throttle-blip that helps rev-match during downshifts. Yes, even in an automatic, rev-matching helps if you’re manually downshifting.
Of course, this is hard to do without having an ECU and TCU that allows for it. Fortunately, the C63 Black Series shares a lot with the CLK63 Black, meaning this upgrade isn’t difficult to do by Weistec. The TCU programming is based off the C63’s rev-match feature since it uses the same engine and 722.9 transmission. Once done, downshifts are smoother but more aggressive for racecar-like, paddle-shifting performance.
So, now, David has his Euro-Spec CLK63 Black Series with a few Weistec upgrades, but he doesn't have plans to go any further. He’s achieved his goals with the car - a fun, rare vehicle that still remains OEM-spec under the hood and California SMOG friendly. David remarks, “I do plan to keep this gem long enough until it is eligible for a chance to showcase at the Legends of the Autobahn during the Monterey Car Week in the future.” So, the car show bug isn’t gone, it has just matured. It’s fitting to the CLK63 Black Series, an upper-class car with the sound and finesse of a performer.
Between now and that future Monterey event, David has only one goal, “Just to maintain and upkeep it in tip-top shape, the car is meant to be driven, but I have and will be reserving the driving for fun-miles-only.” That’s part of the problem for him, though, “The dilemma of me oversharing the joy on driving this car will make it harder for me to obtain another one.” He closes with this, “(it was) a model originated from a racing heritage, from Le Mans to the DTM, and a variation to celebrate the achievements on a glorious label that turned from a tuning shop to OEM performance arm.” What a celebration, indeed.
Story by Justin Banner
Photos by Antonio Alvendia
If you like this Black Series, you can find additional Mercedes-Benz content at mercedes.fcpeuro.com, as well as more build features like this one here. If there's anything specific you would like to see, or if you have any questions/comments, leave them in the comments section below.
Written By: Antonio Alvendia
FCP Euro Content Producer and Sharpshooter Antonio Alvendia is an aficionado of cameras, rare wheels and die cast cars. He got the bug for European car culture by taking photo trips to automotive museums and racetracks in the UK, Germany, France, Belgium, and Italy... and began buying E39 BMW wagons shortly thereafter. Now he is making plans to achieve a bucket list goal of shooting the Nurburgring 24H race. ••• Instagram : @antoniosureshot