Luxury Super Sports Sedan Comparison
Audi RS7 vs. Mercedes-Benz CLS63 AMG S vs. Porsche Panamera Turbo
Power. Can you ever have enough? That's a question our predecessors spent a great deal of time discussing during the bad old days of the 1980s. These days, we Motor Trend scribes are often asking the opposite. Can a car have too much power? More than 99 percent of the time, the answer is hell, no -- the Ferrari F12 berlinetta might be the world's single, overpowered example -- but as the months and years roll on by, the embarrassment of riches that constitutes a comparison test like this one is, well, totally embarrassing. Allow me to illustrate my point: We have three four-door sedans that make 1657 horsepower combined. For the sake of hyperbole, that's more power than a 1200-hp Bugatti Veyron Super Sport combined with the 455-hp Chevrolet Corvette Stingray. And we asked Porsche for the even more potent Panamera Turbo S, but that 570-hp monster wasn't revealed (in Tokyo, then Los Angeles) until one week after we concluded this especially power-dense test. (MT writer Mike Febbo wanted to name it "Menage a Torque.")
That leaves us with the regular-flavor, refreshed-for-2014, 520-hp, 4.8-liter, twin-turbo V-8 Porsche Panamera Turbo, the weakest car in this test by 40 ponies. What a world! Next up is the all-new Audi RS7 and its twin-turbo 4.0-liter V-8, good for 560 hp. Those of you familiar with our work will remember that when we had our hands on the similar-engined 520-hp Audi S8, we took that car to the K&N Engineering dynometer, where it put down 479 hp to the wheels. If you factor in a 20-percent drivetrain loss to things such as the eight-speed ZF transmission and AWD hardware, that's about 575 hp for the S8. The RS7 employs larger turbochargers than the S8 to produce the extra power, and while we didn't get to put the swoopy, slope-backed red car on a dyno, our collective butt-meter tells us it's making much more power than advertised. But as far as advertised power goes, of course the king of this test is the Mercedes-Benz CLS63 AMG S Model with its twin-turbo, 5.5-liter V-8 churning out 577 hp. We happened to dyno the identically engined E63 AMG a little while back, and that car put 541 ponies down to the ground -- that's 676 hp when factoring in a 20-percent drivetrain loss. One final note: We wanted the new BMW M6 Gran Coupe to be a part of this test, but the regular M6 GCs had just been pulled from BMW's fleet to make room for the new M6 Gran Coupe Competition Package cars. Alas, none was available.
We took our three steroidal German friends to the test track. Jaws dropped. The two "slowest" cars actually tied: The CLS63 and the Panamera Turbo each required 3.4 seconds to hit 60 mph. They're slowpokes compared with the RS7, which hit 60 mph in a remarkably quick 3.2 seconds. It feels weird even typing that number: 3.2 seconds to 60 mph is the quickest time we've ever recorded for a four-door vehicle. The previous record was 3.4 seconds for the 2014 E63 AMG.
The quarter-mile numbers are equally mind-boggling, though not record-breaking. Last place goes to the Panamera, which lollygagged its way down the quarter in 11.8 seconds at 116.4 mph. That last sentence is an attempt at humor, as 11.8 seconds is ridiculously quick. In fact, the last 550-hp Panamera Turbo S we tested required 11.8 seconds to go 1320 feet. The Mercedes was even fleeter, needing just 11.7 seconds to do the same, with an extremely fast trap speed of 122.7 mph. Still, the RS7 got there first, taking just 11.6 seconds to crack the quarter, tying our previous four-door quarter-mile champ, the E63 AMG. The Audi's trap speed -- 120.4 mph -- trailed the CLS63's, but a win is a win.
Things reversed once we started turning the steering wheel. Around our figure-eight course, the hyper-quick RS7 came in last with a time of 24.2 seconds and a max g of 0.95. The Mercedes remained in the middle, lapping the figure eight in 23.9 seconds with a max g of 0.97. (The Ferrari 458 Italia required 24.0 seconds to go around our figure eight.) Still, the Panamera Turbo is the king here, doing the deed in just 23.7 seconds while pulling a max g of 1.03. The Lexus LFA took 23.7 seconds to do the same, and it weighs almost 1000 pounds less than the purple Porsche. To get an even better handle on how these three would handle, we decided to take them to the Streets of Willow and let our favorite race driver, Randy Pobst, have a go. The numbers were interesting -- specifically second and third places. The CLS63 AMG was the slowest around the 1.6-mile road course with a time of 1:24.71. The concept of slow is extremely relative, as we had Randy in an Aston Martin V-12 Vantage S that same day, and he needed 1:24.85 in the DayGlo Brit. The Audi RS7 was second with a time of 1:24.30, beating the Benz.
First place with a bullet was the Panamera Turbo. Randy lapped that sucker in 1:22.68. (Just to give you some idea of how quick the big Porsche is, the 662-hp Shelby GT500 needed 1:23.48.) The Ferrari 458 Italia was quicker, but not much: 1:22.30. The Panamera is actually exactly as fast as the track-day special Chevy Camaro 1LE. That's impressive and we were all duly impressed, though not quite as much as Randy. He emerged from the Porsche and proclaimed, "This is it! This is the best car here. Those other two aren't even in the same league!"
The Mercedes stumbled because of its inferior tires. For who knows what reason, the CLS63 comes equipped with Continental ContiSportContact 5Ps -- fine street tires, but they weren't much good on the track. We had to replace both fronts after Randy's third lap. The Pirelli P Zeros on the RS7 held up a bit better, but were basically dead after two days on the track. The Panamera Turbo came strapped with Michelin Pilot Super Sports that didn't even show wear. Driving the Mercedes and the Audi back to back on the Streets, I preferred the way the Mercedes felt, because the Audi understeers (i.e., plows) like crazy. I felt the same way around the figure eight. However, on the track, the CLS63 was sold out by those Continentals.
The Porsche, as Randy indicated, was head and shoulders above the other two. "Driving the Panamera is far more instinctual than with the other two," said Febbo. "I'm not thinking about 'Can I get on the gas yet?' I find myself just unwinding with my foot heading toward the mat before I wonder if I'm going to run wide. After a couple of laps, I'm thinking so far ahead that it's more meditation than mental exercise."
Associate editor Rory Jurnecka agreed. "The amount of confidence the Porsche instills is almost frightening. I'm not sure I've been around the Streets faster in any other car, and I've driven the track in quite a few."
What I found most surprising about the Panamera was its willingness to get sideways under hard throttle. Especially because, like the other two, it's AWD and therefore (supposedly) reluctant to drift. And what I found most surprising overall was how softly sprung the RS7 is. Watching Randy lap the Audi, the phrase "on its door handles" kept running through my mind. Jurnecka explained, "Lots of body roll/wallow. But somehow it's less comfortable, with huge up/down movements. It rides like a car that's been lowered poorly." As for the Mercedes at Streets, Febbo said, "Have the engine and transmission ever met? The CLS63 doesn't have the immediacy of the other two. Big hesitation on upshifts, and it seems to want to shift at different times, not always at redline." As odd as this next part sounds, there was something underwhelming about the Benz. "It felt stodgy," added Jurnecka. "Very fuddy-duddy. It was a chore to get it to move around."
Yes, we know no one buys 4500-pound sedans to visit racetracks. OK, fine -- two or three dudes do, but they're weirdos. With that in mind, we set out to discover which of these three monstrously potent German super-sedans is best to drive in our twisted little version of the real world: the epic canyon roads above Malibu. As the environment changed, so did our impressions of the cars. The CLS63 actually sank a little. "Second gear is way too tall for the canyons, and obviously first gear is almost unusable," commented Febbo. "This isn't meant for canyon driving. It doesn't launch out of tight turns, which is exactly what I want from AWD turbo cars." My own notes read, "Can a 577-hp car feel dull? You wouldn't think so, but in this company, the CLS63 AMG does." Jurnecka best summed up the Mercedes: "That's not to say it's a bad car. It's just that the CLS63 isn't involving in any way. Compared with the other two, it does nothing for me."
Here's a handy cheat sheet that might help explain: We give the Audi's engine an A+ and its ZF eight-speed auto an A; the Porsche's engine gets an A with its near-perfect seven-speed dual-clutch getting an A+. The AMG gets a solid A for the handbuilt megamotor, but only a C for the seven-speed wet-clutch auto. Sometimes things are that simple.
The Audi, on the other hand, shot way up in our estimation. Unlike on Streets, there were certain places along our canyon drive where I liked the RS7 more than the Panamera Turbo. As it happens, every one of those places was a straight stretch of road.
"Mein Gott, this thing is fast," said Febbo. Jurnecka added, "Holy mother of god, this engine is fantastic. The sound, the pull, and the quick shifts make it feel like a rocket." Febbo pointed out, "Engine and trans are superb in the wild. It cruises along in traffic like it's a 2.0-liter turbo, but open the taps and it shoots through holes in traffic like a sniper rifle." My notes were more jumbled but similar in sentiment. "This monster just annihilates the road in front of it with torque and power and, holy wow! Color me amazed." In fact, I take back all the nasty things I said about it on the track. In the real world, the Audi is simply incredible. However, it's not incredible enough.
When we had the cars at Streets of Willow, we also had the Aston and the hyper-rare Jaguar XKRS-GT. While the hard-core Jag was marginally faster than Panamera Turbo (1:22.53 versus 1:22.68), the consensus was that the Porsche was the best car at the track. I repeat: The heaviest car of the group, the one with heated/cooled rear seats and powered sunshades, was more satisfying to whip around a road course than an RS product, an AMG, a V-12 Aston, and a blistered, Nürburgring-birthed Jag. That, my friends, is incredible enough.
"Has there ever been a car so adept at tearing up a racetrack by day and chauffeuring four adults to dinner in total comfort by night?" asked Jurnecka. "If so, I haven't driven it." Febbo continued this theme: "The Panamera feels like half the mass of the Mercedes. It feels willing to do anything. This is one of the best cars anywhere, ever."
If the purple Porsche has a weak point (besides the color, though opinions were painfully split), it's the bloody-nose as-tested price: $195,510. In theory, you could get a Panamera Turbo for $142,275, which isn't that much more dear (if you're rich) than the RS7's as-tested price of $125,595. But if you can find a no-option Panamera Turbo on a dealer lot in America, I'd like you to buy my lottery tickets. Febbo proclaimed: "The Porsche is the only car here I'd actually buy with my money." As fanciful and farfetched as that sounds, he's right. The Panamera Turbo is simply a cut above.
Third Place: Mercedes-Benz CLS63 AMGIt sounds crazy, but the world's third-quickest sedan feels dull compared with the others. Tough crowd.
Second Place: Audi RS7One of the greatest engines on sale today. One of the pushiest, most understeering chassis, too.
First Place: Porsche Panamera TurboThe shift paddle travel is too long. Oh, who are we kidding? If you can afford it, you should buy it, because its one of the world's best cars.
|2014 Audi RS7||2014 Mercedes-Benz CLS63 S AMG||2014 Porsche Panamera Turbo|
|DRIVETRAIN LAYOUT||Front-engine, AWD||Front-engine, AWD||Front engine, AWD|
|ENGINE TYPE||Twin-turbo 90-deg V-8, aluminum block/heads||Twin-turbo 90-deg V-8, aluminum block/heads||Twin-turbo 90-deg V-8, aluminum block/heads|
|VALVETRAIN||DOHC, 4 valves/cyl||DOHC, 4 valves/cyl||DOHC, 4 valves/cyl|
|DISPLACEMENT||243.7 cu in/3993 cc||333.3 cu in/5461 cc||293.3 cu in/4806 cc|
|POWER (SAE NET)||560 hp @ 5700 rpm||577 hp @ 5500 rpm||520 hp @ 6000 rpm|
|TORQUE (SAE NET)||516 lb-ft @ 1750 rpm||590 lb-ft @ 2000 rpm||516 lb-ft @ 2250 rpm*|
|REDLINE||6600 rpm||6400 rpm||6500 rpm|
|WEIGHT TO POWER||8.0 lb/hp||7.6 lb/hp||8.7 lb/hp|
|TRANSMISSION||8-speed automatic||7-speed automatic||7-speed twin-cl auto|
|SUSPENSION, FRONT; REAR||Multi-link, air springs, adj shocks, anti-roll bar; multilink, air springs, adj shocks, anti-roll bar||Multilink, coil springs, adj shocks, anti-roll bar; multilink, air springs, adj shocks, anti-roll bar||Control arms, air springs, adj shocks, anti-roll bar; multilink, air springs, adj shocks, anti-roll bar|
|STEERING RATIO||15.9:1||14.1:1 (near center)||17.1-13.8:1|
|BRAKES, F;R||15.4-in vented, drilled disc; 14.0-in vented, drilled disc, ABS||14.2-in vented, drilled disc; 14.2-in vented, drilled disc, ABS||15.4-in vented, drilled ceramic disc; 13.8-in vented, drilled ceramic disc, abs|
|WHEELS||9.0 x 21-in, cast aluminum||9.0 x 19-in; 10.0 x 19-in, forged aluminum||9.5 x 20-in; 11.5 x 20-in, cast aluminum|
|TIRES|| 275/30R21 98Y|
Pirelli P Zero
| 255/35R19 96Y; 285/30R19 98Y|
Continental ContiSportContact 5P
| 255/40R20 101Y; 295/35R20 105Y|
Michelin Pilot Super Sport
|WHEELBASE||114.8 in||113.2 in||115.0 in|
|TRACK, F/R||64.3/64.0 in||63.3/64.1 in||65.2/65.2 in|
|L x W x H||197.3 x 75.2 x 55.8 in||196.7 x 74.1 x 55.4 in||197.4 x 76.0 x 55.4 in|
|TURNING CIRCLE||39.0 ft||38.5 ft||39.3 ft|
|CURB WEIGHT||4493 lb||4402 lb||4510 lb|
|WEIGHT DIST, F/R||56/44%||55/45%||53/47%|
|HEADROOM, F/R||36.9/36.6 in||36.9/36.1 in||38.0/38.2 in|
|LEGROOM, F/R||41.3/37.0 in||42.1/35.0 in||41.9/33.3 in|
|SHOULDER ROOM, F/R||57.2/55.9 in||57.1/56.5 in||51.9/51.7 in|
|CARGO VOLUME||24.5 cu ft||15.3 cu ft||15.3 cu ft|
|ACCELERATION TO MPH|
|0-30||1.3 sec||1.4 sec||1.2 sec|
|PASSING, 45-65 MPH||1.7||1.6||1.8|
|QUARTER MILE||11.6 sec @ 120.4 mph||11.7 sec @ 122.7 mph||11.8 sec @ 116.4 mph|
|BRAKING, 60-0 MPH||101 ft||106 ft||104 ft|
|LATERAL ACCELERATION||0.95 g (avg)||0.97 g (avg)||1.03 g (avg)|
|MT FIGURE EIGHT||24.2 sec @ 0.83 g (avg)||23.9 sec @ 0.85 g (avg)||23.7 sec @ 0.87 g (avg)|
|1.6-MI ROAD COURSE LAP||1:24.30 sec||1:24.71 sec||1:22.68 sec|
|TOP-GEAR REVS @ 60 MPH||1900 rpm||1500 rpm||1400 rpm|
|PRICE AS TESTED||$125,595||$116,985||$195,510|
|AIRBAGS||Dual front, front side, f/r curtain, front knee||Dual front, front side, f/r curtain, front knee||Dual front, f/r side, f/r curtain, front knee|
|BASIC WARRANTY||4 yrs/50,000 mi||4 yrs/50,000 mi||4 yrs/50,000 mi|
|POWERTRAIN WARRANTY||4 yrs/50,000 mi||4 yrs/50,000 mi||4 yrs/50,000 mi|
|ROADSIDE ASSISTANCE||4 yrs/unlimited||Unlimited||4 yrs/50,000 mi|
|FUEL CAPACITY||19.8 gal||21.1 gal||26.4 gal|
|EPA CITY/HWY ECON||16/27 mpg||16/22 mpg||15/24 mpg|
|ENERGY CONS, CITY/HWY||211/125 kW-hrs/100 mi||211/153 kW-hrs/100 mi||225/140 kW-hrs/100 mi|
|CO2 EMISSIONS||0.99 lb/mi||1.06 lb/mi||1.08 lb/mi|
|RECOMMENDED FUEL||Unleaded premium||Unleaded premium||Unleaded premium|