- 16 Min Read
- By: Christian Schaefer
Two Is Better Than One: 5 Of Our Favorite Twin-Turbocharged European Cars
Turbochargers have been in use for a lot longer than many seem to realize. Lockheed’s P-38 Lightning used two turbocharged Allison V12s to power it along back in the 1940s. By the 1970s, turbocharging had become a big focus around race tracks after the Porsche 917/10 and 917/30, utilizing two turbochargers, absolutely obliterated its Can-Am competition. These days we use turbochargers mainly for efficiency reasons. Smaller displacements can use boost to achieve necessary power levels while maintaining a fuel-sipping demeanor. Thankfully, manufacturers haven’t resigned themselves entirely to the idea of boost hungry, go-fast machines. These few models represent some of the coolest boosted European cars of the last twenty years, and they all use a pair of turbochargers.
Porsche 996 Turbo
Even with inflation or appreciation caused by the Pandemic, the Porsche 996 remains a good value. In its heyday, the 996 was a polarizing force on the road and the race tracks. Many hated them for their history-defying headlights but couldn’t deny the performance that they offered. Twenty years on and their values are on the rise from what seems to be the bottom of their depreciation curve, aided by the gasoline-free future and the public’s rediscovery of the chassis engineering that went into creating the 996. Every model has seen this bump, but no trim remains as good a value as the Turbo.
The 996 Turbo debuted in the states for the 2001 model year and ran through 2005. Prices are going to vary depending on the options equipped, mileage, condition, and modifications. Typically, modifications add little to the resale value, but tasteful and OEM+ type changes work well for the Turbo. Higher mileage and heavily used examples equipped with the automatic transmission work against the value and can go for under $40,000. Middle spec examples, ones with decent mileage but service records and manual transmissions, will bring in the range of $45-60,000. A low mileage example with a distinctive color, factory exclusive options, or very tasteful modifications can bring upwards of $80,000 if the conditions are right. Porsche’s can be tricky, and you get what you pay for.
But what you’re paying for is an engine derived from multi-24 Hours of LeMans winners wrapped in a chassis that won the 24 Hours of Daytona. Even the oldest well-sorted, stock 996 Turbo can still keep up with today's performance cars, and that’s thanks to the twin-turbo monster in the back. Slung out behind the rear wheels is Porsche’s M96.70, a 3.6-liter twin-turbocharged horizontally-opposed six-cylinder engine, the same primary engine platform that has powered every 911. Even though the engine shares the M96 designation like those fitted to the normally aspirated Carrera’s, it is a whole different beast. The M96.70 uses essentially the same crankcase and bottom end from the older air-cooled models. Fitted to them are two pairs of water-cooled cylinders and cylinder heads. Adding on a couple of turbochargers gave the Turbo 415 horsepower and 415 lb-ft of torque. However, the engines are incredibly stout from the factory and can handle well above that figure with some tuning. Complete builds can produce engines capable of withstanding upwards of 1400 horsepower while still functioning as a street-driven vehicle.
Turning all of that internal combustion into forward movement is the Getrag-built G96.50 six-speed manual transaxle or a Mercedes-built 722.6 five-speed automatic that was called “Tiptronic.” Both boxes sent power to the front and rear wheels, helping the Turbo launch hard and put all of its power down. Both transmissions can handle an increased power level, but the manual will be able to take more before modifications are needed. Assisting the drivetrain is a MacPherson strut front suspension and multi-link rear, while coil-over suspension does the damping at each corner. In rare cases, the optional X74 suspension package may be fitted. It replaces the standard struts and springs with lowered and stiffened units designed for more aggressive driving. The 996 Turbo can be a weekend track weapon with the right aftermarket suspension components, thanks to its motorsport-oriented chassis design. The all-wheel-drive, wide track, and huge tires give it an immense mechanical grip that lends itself to driving at the limit.
Of course, track days and spirited driving aren’t for everyone, and in stock form, the Turbo is more of a grand tourer than an all-out racer. The interiors are full of leather, the seats comfortable, and the engine settles right into cruising without excess noise. Heated seats are likely to be present, but not too much else will be. Technology isn’t their strong suit; Porsche Communication Management was available to give the Tubo a large LCD screen for the radio, but it was an option. The standard radio still had a cassette player. A Bose audio system was also available as an option. However, just about a year ago, Porsche introduced the Porsche Classic Communication Management Plus. In short, it’s a modern audio interface and head unit, complete with Apple CarPlay and Android Auto, but in a plug-and-play package for the 996. It isn’t cheap, but neither is Porsche ownership. The interior of the 996 Turbo sits at an interesting point in time for cars; it isn’t analog, with LCD screens and electronically controlled HVAC, but it isn’t a technology-packed modern vehicle. A true sweet spot in interior equipment for simplicity and modernity.
Every 996 Turbo is going to look roughly the same as Porsche didn’t produce an updated version. Each model uses a wide body with large radiator inlets in the front bumper, air intakes in the quarter panels, and heat vents on the sides of the rear bumpers. The standard wheel is the “Turbo Twist,” a distinctive twisted five-spoke design.
As far as twin-turbo vehicles go, the 996 Turbo is incredibly reliable. The only mechanical issue the power plants have ever needed to sort out regards loosening coolant pipes. Once they’re fixed, regular maintenance is all it should need. The transmissions, too, are very reliable. The automatics don’t tend to break under stock power levels and are relatively inexpensive to repair by a trained Mercedes or Porsche independent shop. The manuals will take tons of abuse, but the stock clutch system is needlessly complicated and prone to failure. Replacing it with the clutch system from the GT2 solves the problem for good. Interior wear can be similar to every European car from that era. The electrics can be a little wonky but generally aren’t a problem. Soft surfaces will peel and shrink if left in the elements for long periods, as will the optional carbon-look interior pieces. If you’re looking for a supremely capable but reliable turbo monster for a weekend car, you’ll be hard-pressed to find a better choice.
BMW 335i E90
The BMW 3-series has been a perennial contender since its debut in the mid-seventies. Family hauler? Definitely. Sports sedan? Some say the best. Touring Car champion? Absolutely. But every street model featured a normally aspirated engine when it left Munich. That is until the E92 335i left the factory. Its turbocharged engine was the first fitted to a production compact sedan since the 2002 Turbo, BMW’s first turbocharged production car. The changing emissions regulations and modern technology made the switch to boost a logical and necessary choice for BMW. Yet what they created will be remembered for decades to come, like the best of their naturally aspirated engines.
The newest BMW E90 335i examples are nearly ten years old. They’ve been out of warranty for several years, and many have gone through multiple owners. Finding a relatively clean example may be tough but not impossible. The scuzziest of beaten examples is a sub-$10,000 car, and the nicest, stock example only brings around $15,000. There are tons of examples out there with all sorts of mileage, modifications, and conditions. Pricing shouldn’t change based on model year, drivetrain, or roof function. Finding the right one for a given application will only take time.
What’s going to make the E90 335i a car to remember is what BMW stuck under the bonnet. In true BMW fashion, the N54B30 was a smash hit out of the box. The twin-turbocharged 3.0-liter inline-6 features direct fuel injection, ultra-precise Piezo injectors, and two single-scroll turbochargers that blow through an air-to-air, front-mount intercooler. Altogether the N54 in the 335i put out 300 horsepower and 300 lb-ft of torque at only eight pounds of boost. The N54 was a marvel in its time, winning awards right out of the box for its engineering. However, the engine’s true colors were revealed once they hit the hands and workshops of tuners. Turning up the boost and fitting freer-flowing exhaust components unlocked oodles of horsepower from the restricted N54. Tuners were seeing upwards of 400 horsepower and torque without the engine breaking a sweat. The aluminum engine block uses cast-iron cylinders giving the bottom end fantastic strength when coupled with the forged crankshafts and connecting rods. Built right, and the N54 can push four-figure power levels.
But there’s more to the 335i than its engine. The E90 chassis is fantastic in its own right, with any of the generation’s engines fitted. The decades of sublime chassis tuning by BMW didn’t end with the E90, as it was and still is capable of being a competitive race car. On the street, they deliver a characterful and sporty driving experience that lends itself to the driver. The 335i is no exception and can be fitted with some of the suspension components of that generation’s M3 to enhance its natural handling abilities further. Keeping with the theme of driver engagement, BMW offered the 335i with a six-speed manual transmission as standard, though an optional six-speed automatic was available. The manual box is smooth shifting and can hold over 400 horsepower, but beefier supporting components and more frequent servicing are needed. The automatics don’t love extra engine performance but can withstand over 1000 horsepower with enough money thrown at them.
As always, there is a decent variance within just the 335i chassis’. It was available as the E90 sedan, the E92 coupe, and the E93 convertible. Both the coupe and sedan were offered with rear-wheel drive or with xDrive all-wheel-drive. Some standard equipment varies between the models, with the coupe getting the sport suspension as standard while the sedan and convertible had it as an option. The Logic 7 13-speaker sound system, adaptive xenon headlights, eight-way adjustable sport seats, leather-wrapped steering wheel, and 17”x8” Style 159 wheels are shared between all of them.
It’s a versatile chassis with plenty of variation between examples and a powerful and capable engine under the hood. However, that comes at a cost. While the 335i isn’t too expensive upfront, the N54 will likely go after your wallet at some point. They have a checkered reputation; the reliability of its components balances their prowess for producing big horsepower and responsiveness to modifications. Like any typical BMW engine, it leaks oil regularly, usually from the oil filter housing, valve cover, or oil pan gasket. On top of that, the high-pressure fuel pumps do not like to last very long, nor do the Piezo-style fuel injectors. Both fuel system issues can get costly quickly. Check this out to read up on the N54 and learn its strengths, weaknesses, and quirks. High mileage cars will likely have some interior rattles and need attention paid to the suspension. Things like the swaybar endlinks and control arm bushings love to get sloppy around 80,000 miles, if not sooner. Although it’s a BMW, these are now tuner cars and have to be treated as such. Constant maintenance, while time-consuming, is the name of the game here.
C7 Audi S6
The S6 has always been a contender for a fast family car. So many buyers have gone the route of SUVs in the name of family and safety that fast sedans just don’t have the following they did decades earlier. That doesn’t mean manufacturers have given up on them, though. The performance sedan market is alive and well, with Mercedes Benz, BMW, Audi, Porsche, and Jaguar competing in that space. Of those, the Audi is the least flashy, going about its way with simple but attractive lines, full-time all-wheel drive, and a twin-turbocharged engine under the hood. It’ll get you in and out of anywhere as quickly and comfortably as most anything else.
The S6 in question here is the fourth generation, known as the C7. Audi offered it between 2012 and 2018, giving it a minor refresh starting with the 2016 models. Asking prices are going to be determined by the model year, mileage, and trim package. Trims are easy as the only two offered were the basic Premium Plus and the top-spec, Prestige. Prestige models command only a few thousand more on average than the Premium Plus equipped S6s, so the prices are ballpark numbers for both models. The newest 2018 examples that still carry a factory warranty are asking near the $60,000 mark. Earlier models with under 40,000-miles are in the $45-55,000 range while 40-80,000-mile examples are in the sub-$45,000 range, bottoming out in the high twenties.
Powering the super-saloon is a 4.0-liter V8 strapped with, you guessed it, two turbochargers. Audis and forced induction go hand in hand, with a majority of their performance sedans having used boost in one form or another since they debuted, and the C7 S6 is no different. The 4.0 TFSI unit in the C7, going by the designation CEUC, uses a pair of twin-scroll turbochargers to deliver excessive torque on the low-end while providing plenty of power up top. The pre-facelift models produce only 420 horsepower and 406 lb-ft of torque, though the later cars received a bump to 450 horsepower. Like BMW’s N63, it uses a hot-vee configuration with the intercoolers and turbochargers sitting in the engine’s valley. It also features Audi’s “cylinder on demand” technology. The system will deactivate half of the cylinders when the engine is running under partial load, like on the highway, to achieve up to 27 mpg. Active Noise Control and active engine mounts work with the cylinder deactivation to ensure no changes from the engine are felt by the driver.
Backing up the power unit is Audi’s seven-speed, double-clutch, S-Tronic gearbox. The engine and transmission work together with the Quattro all-wheel-drive system to snap off 0-60 times of about four seconds. When you want to be civil, though, you can change up the suspension, transmission, and engine settings using Audi Drive Select. Different modes include sport, Dynamic, and Comfort, offering different responses and feelings based on the mode selected. Comfort relaxes the adaptive air suspension, making it as smooth as it possibly can be for driving the kids to school or cruising the freeway on a road trip. However, when the going gets sporty, the air suspension sharpens up to help the 4500lb sedan feel light on its feet.
At its softest, it’ll feel relaxed and tame, though the interior will constantly remind you of what you’re sitting in. Adorning the interior of every S6 is leather upholstery and trim as far as the eye can see. The seats, front, and rear use a diamond stitch pattern, while the fronts feature deep bolstering to keep the occupants held in place. Where there isn’t leather, aluminum accents or buttons are present. Pre and post-facelift interiors utilize some different components, so be wary of that when buying. Older models use a proprietary system for the Multi-Media Interface, or MMI, system. It also uses in-car 3G WiFi and Google Earth data for the navigation system. Later models use a universal interface, providing the same features to Android and Apple products.
For such an expensive model with lots of features and horsepower, the maintenance should be fairly simple. The newest models are just about three years old, with more than a few still carrying factory warranties. For those out of warranty, though, there isn’t too much to worry about. Audi’s first hot-vee engine in a street application is generally trouble-free and only really experiences issues with the PCV system, though turbocharger longevity can be an issue. Whether due to a poor turbocharger design or a lack of oil flow, the turbochargers are known to fail pretty spectacularly, with the only fix being a complete replacement. They also suffer from some smaller issues like coolant line leaks. We offer a complete turbocharger replacement kit, but it isn’t cheap. The S-Tronic is pretty reliable, but Mechatronic failures do happen. Proper maintenance is critical to their longevity. Beyond that, typical wear items such as motor mounts, control arm bushings, and brakes tend to last shorter than something like an A6 or A4. It’s a high-performance model, and it requires maintenance on par with that.
Mercedes-Benz AMG S65
Best is subjective. The best car for a family of five is not going to be the same as the best car for someone who lives alone; in the same way, a MINI isn’t going to be the best choice for a mafia boss. They, realistically, would need something that would wrap them in the pinnacle of luxury at all times and have the power to get out of sticky situations. Mercedes’ S-Class has always been a benchmark in the executive sedan segment, but when they strapped their W221 with a V12 and two turbochargers, they managed to build, arguably, the baddest European executive sedan we may have ever seen.
Depreciation is a natural effect in AMG-land. Their models are so advanced when new that service costs often become laughable once out of warranty, making the vehicles a monetary liability to use. That effect has affected the 2007-2013 S65 AMG but not to the degree of other AMG models. Once a $211,000 vehicle, a used S65 can be picked up for significantly less. Low mileage examples with around 20,000-miles range in asking price between $75-90,000. Doubling or tripling the mileage brings the asking price to the $45-60,000 range, and examples with 75,000+ miles can be acquired in the mid-thirties. Prices will be affected by condition and options, but always choose the example with the best service history you can afford.
There is a lot to love about the S65 AMG from a distance. Its world-class luxury interior and subtle yet flashy bodywork set it apart from anything else on the road except for another AMG. But the real peach is under the hood. Mercedes has built their AMG brand around their snarling V8s that make American muscle cars quiver, but a V8 wasn’t enough for the top-spec S-Class. Instead, it‘s fitted with the M275 E 60 AL, also known as the M275 AMG, a 6.0-liter twin-turbocharged V12. In S65 trim, the enormous engine forces out 603 horsepower and 738 lb-ft of torque. Even in a 5000lb sedan, the oomph that the M275 provides is enough to give it a 0-60 time of around four seconds. You’ll be lucky to achieve that time regularly, though, as the torque comes on so quickly and in such force that the power will turn the rear tires into smoke without blinking an eye. Rolling burnouts at highway speeds are not out of the question either. Add on some aftermarket downpipes and an aftermarket ECU tune, and you’ll have nearly 900 lb-ft of torque at your disposal.
In true Mercedes fashion, they did a complete job ensuring that you’re in the utmost comfort as you struggle to put all of that power down. The list of standard equipment on the S65 is long enough to make a CVS receipt jealous, with every possible luxury-focused option you’d expect. A rearview camera, front and rear parking sensors, front seats with massage, adjustable/active bolsters and enhanced headrests, a 15-speaker Bang & Olufsen sound system, a dual-screen rear-seat entertainment system, sport steering wheel, shift paddles, an enhanced instrument cluster, and AMG-specific leather and trim all work together to remind you that you’re driving something special.
Helping the driver keep control of the V12 behemoth is Mercedes’ Active Body Control suspension. It’d be challenging to get any more AMG than equipping a car with an overly complicated system that works very well when it’s working correctly but causes owners nightmares during repairs. And in short, that is sort of what the ABC system is. Whereas the AIRMATIC system uses compressed air to fill air springs that work with traditional dampers, the ABC uses a hydraulic system to control several aspects of the suspension. For starters, the suspension carries full self-leveling capabilities and on-the-fly height adjustment at speed for better fuel economy and handling. Various sensors measure the pitch and roll of the vehicle, allowing the ABC computer to adjust for any extreme conditions. The spring and damper setup uses a traditional Mercedes adaptive shock with a standard coil spring. Fitted atop is a hydraulic piston that counteracts negative pitch and roll conditions when filled with hydraulic pressure. When functioning as intended, it is an imposing system that provides nearly unmatched comfort. However, it hasn’t proven itself to be the most reliable.
The ABC suspension gets its hydraulic pressure from the power steering pump. Through various pressure sensors, Pentosin fluid is moved about the suspension as the controlling computer sees fit. Both fluid-based problems and electrical issues can hamper any ABC system. Fluid leaks are a standard business, sprouting from the pumps, lines, and struts. Electrical malfunctions from broken sensors are also not uncommon and can cause the vehicle to enter limp mode. Repair costs vary wildly from nearly $2000 for a new pump to $150 for an accumulator. ABC delete kits are popular but are not offered for the W221, so the only option is to fix the suspension when it goes wrong.
Looking elsewhere around the car, there are issues, but none as close to the ABC. The engine has no catastrophic issues but struggles mightily with its coil packs. Unlike typical coil-on-plug designs, they use one large ignition coil per bank. The entire coil has to be replaced if only one cylinder is misfiring, and they run around $1200. Transmission issues are largely avoided here, with the tried and true 5G-Tronic five-speed automatic transmission. Inside the cabin, massaging seat failures, stereo issues, and various other electrical gremlins can present themselves, though not very often. It isn’t precisely trouble-free, but I’m sure you had that idea going into this section. What it lacks in outright reliability, it makes up for in sheer power and highway destroying ability. Excess has its limits, and the S65 AMG is the line.
BMW X5M F85
The performance SUV didn't exist twenty years ago, but these days, it is one of the fastest-growing markets worldwide. The Alfa Romeo Stelvio Quadrifoglio, Lamborghini Urus, Aston Martin DBX, and Bentley Bentayga Speed are just the latest contenders in the class, going up against the veterans that are the Cayenne Turbo and X5M. For BMW’s sake, they have the advantage of building the most road-focused challenger of the bunch in non-M form. Adding the stiffer suspension, improved engine, revised bodywork, and bespoke interior take the X5 to another level and allow it to put up a fight for the best model in the performance SUV segment.
The X5M has only just recently had its third-generation model debut to the world. Going for a second-generation X5M, dubbed the F85, will be the easiest way into meaningful performance SUV ownership from BMW. They were offered between 2015 and 2018 before the new X5 took over. A nicely optioned F85 X5M with around 30,000-miles goes for about $75,000. Early examples with nearly 100,000-miles are quite a bit less expensive, commanding anywhere from $35,000-45,000. Only the 2018 models with under 50,000 miles may still carry a factory warranty. There weren’t any LCI updates for this chassis, so the early cars will have the same equipment as the later examples.
The heart of the beast is BMW’s S63, a 4.4-liter V8 utilizing two twin-scroll turbochargers mounted in the engine’s valley. The engine is based on the N63 out of the xDrive50i but utilizes a number of improvements from the M Division. Thanks to unique twin-scroll turbochargers and revised exhaust manifold routing, the S63 uses a boost pressure of around 26 psi, over double the N63’s 11.5 psi. Other improvements like a revised oil pan with dual pickups, a larger exhaust camshaft, bigger intercoolers, and an additional engine oil cooler help the S63 produce 575 horsepower and 550 lb-ft of torque in F85 trim.
As the top-spec X5, the F85 gets all of the performance goodies as standard. Massive brakes with blue-painted calipers sit behind one of two unique wheel designs specific to the X5M. Keeping the wheels and brakes attached to the chassis is the M-tuned, active air suspension system. The front coil springs and rear air springs are shorter and stiffer to pair with the recalibrated shocks. Those shocks are part of the Dynamic Damper Control system that adjusts the damping profiles of the shock on the fly to suit the driving conditions perfectly. Selecting the damper settings is done via a toggle switch or through the iDrive system. Different driving modes include Sport, Sport+, Comfort, and ECO Pro. Selecting a mode changes more than the suspension, though. The engine response is modified, the stability control systems change their parameters, and the transmission is sharpened or softened.
The transmission in question here is an eight-speed automatic unit made by ZF. They’re incredibly robust, and with the Sport+ mapping, they can shift nearly as fast as a DCT, while being more reliable. A transfer case mounted to the transmission splits power to all four wheels, forming the basis of the xDrive system. Working with that system to achieve the best possible grip is the Dynamic Performance Control. The DPC uses various speed, yaw, pitch, and roll sensors to distribute the torque to the wheel that will benefit from it the most. Of course, you likely won’t be thinking about all of the nitty-gritty technical details while you’re wrapped in a leather-clad and technology-filled interior. Unique upholstery and seats ensure the occupants are held in place snugly but comfortably at all times. An M-Sport steering wheel and an M-badged instrument cluster and shifter are there to let you know what you’re sitting in.
It isn’t all sunshine and horsepower, though. The S63 suffers from some concerning issues, though in rarer cases than the N63. Unfortunately for owners of either turbo V8, there are serious oil consumption issues. Owners filed a class-action lawsuit against the Bavarians, which eventually led to BMW settling for reimbursements and repairs for those affected by the problems. Coverage from BMW can take away some of the anxiety about ownership, but the possible need for an engine replacement will be there until BMW finds an actual fix. Other minor issues like fuel injector failure, ignition coil failures, turbo coolant line leaks, and general oil leaks can affect the S63, though low frequencies. Other than that, transmission issues are rare, though suspension bushings tend to wear relatively quickly. General maintenance will be more expensive, more critical, and more frequent than an X5 from the same generation, too. Go for the best-maintained example available to cut down on the number of potential problems to navigate through.
If your favorite twin-turbo car didn't make the list, add it to the comments below and let us know why it should be considered!
Owner of a flat-six swapped 1998 Impreza 2.5RS and a 1973 Porsche 914. Horizontally opposed views, only.