What do you really want from your luxury sport sedan?
Four-cylinder engines aren’t what they used to be—they’re way, way better. And considering the goodness of the A4 2.0T’s 252-hp turbo-four, the new turbo-six-powered 2018 S4 must work harder than ever before to justify its premium over the mainstream A4 that slipped by every other car in 0-60-mph acceleration during our huge Big Test comparison of compact luxury sport sedans. The 2018 Audi S4’s upgrades go deeper than just a powerful six-cylinder engine, and we tested the more performance-focused sedan to see how it compares to rivals from BMW, Mercedes-Benz, Infiniti and, well, Audi in the form of our long-term A4.
I’ve spent many months and thousands of miles with our long-term A4, a 2017 model with a 2.0-liter turbo-four making 252 hp and 273 lb-ft of torque. On paper, it doesn’t sound impressive, but the engine is hooked up to a seven-speed twin-clutch automatic transmission and Audi’s Quattro all-wheel-drive system. The car is always responsive, and even when I’m in a lead-footed mood, I have never felt like I needed more power. The thing is, the Mercedes-AMG C43, Infiniti Q50 Red Sport 400, and others are just as much about emotional wants as they are about practical needs. The S4 adds style, status, and power to the A4’s strong overall package.
Under the 2018 S4’s hood is a 3.0-liter turbo-six that produces 354 hp and 369 lb-ft. Unlike my long-term A4, the S4 gets a conventional eight-speed automatic, and its all-wheel-drive system is biased 40/60 front/rear. Our loaded S4 tester included a $2,500 USD S sport package that adds red brake calipers, a sport-focused adaptive suspension, and a rear differential. The adaptive suspension is definitely harsher than my A4, which uses a now-discontinued comfort-oriented version of Audi’s adaptive suspension, but the S4’s system is still everyday-livable. The rear differential can send nearly all of the S4’s torque to one of the rear wheels, if necessary, to keep you moving in the right direction if you accelerate quickly out of a corner (you might feel the effect occasionally if you’re looking for it). I most appreciated the adaptive suspension and red brake calipers, but the value of that package will depend on how hard you plan on driving your car.
Really, the same can be said about the S4, as a whole, especially if you’re also considering a loaded A4. One S4 advantage, not surprisingly, is acceleration. The S4 hits 60 mph from a stop in just 4.2 seconds, reaching that benchmark speed a full second ahead of our already-quick A4 long-termer. That 4.2-second time ties that of an all-wheel-drive Mercedes-AMG C43 we’ve tested and is three-tenths of a second quicker than a rear-drive Infiniti Q50 Red Sport 400. The last-gen S4, which was powered by a supercharged 3.0-liter V-6, reached 60 in 4.4 seconds.
Launching an A4 will pin you to the back of your seat, and the S4 adds to that appeal. When it comes to the sound, however, there’s no comparison. The S4’s engine note sounds more muscular than the 252-hp A4, yet it’s more subdued than the C43. Listen closely in the S4’s Sport mode, and you might be able to make out a crackle from those wonderful quad-exhaust outlets.
“Fairly subtle exhaust note,” said road test editor Chris Walton after driving the S4 at the track, “and as quick as anyone would ever need, but it’s such a sleeper—too much of a sleeper maybe.”
For those who dig styling that’s sporty but doesn’t shout, the S4 will be a good fit. The four exhaust outlets, silver side-mirror trim, and subtle lip spoiler communicate that the sedan is an S4, as do the available red brake calipers on our $65.050 USD tester.
The brakes themselves stopped effectively in 60-0-mph tests, with a 104-foot performance that was 22 feet better than our long-term A4 and also shorter than the C43 (111 feet) and Q50 Red Sport 400 (105 feet), though an all-wheel-drive Kia Stinger GT matched the S4 here. Where the S4 pulled away from that heavier and slightly slower Kia as well as everything else in its class except the Mercedes is on our figure-eight course. This Motor Trend test tracks different driving characteristics including acceleration, braking, cornering, and the transitions between them. The S4 put in a time of 24.3 seconds at 0.82 average g, well ahead of the Q50 Red Sport 400’s 25.6 seconds at 0.74 average g and the C43 4Matic’s 24.8 seconds at 0.77 average g. Although not really in the same class of acceleration as those cars, the Stinger GT AWD turned in a time of 25.2 seconds at 0.77 average g, and our long-term A4 clocked in at 26.3 seconds at 0.69 average g.
Testing director Kim Reynolds called the S4 a “heck of a car” and appreciated that, on the figure-eight course, the Audi had good body motion control: “What I like here is how you can rotate it and slightly drift the tail out on exit,” he said. “It turns-in well (not great, but well enough), but then you can adjust it with throttle.”
That’s helpful info on a sporty car like this, especially if you plan on tracking your S4. Even so, this isn’t a full performance sedan such as the C63 or the RS 4 model sold in other markets, so if most of your driving involves trudging along in traffic to work, you’ll appreciate the S4’s sharp interior. The $500 USD carbon-fiber trim looks great, as does the Virtual Cockpit digital instrument cluster and the crisp graphics on the head-up display. I also find Audi’s MMI infotainment system easy to use, though it can initially take a little time to find semihidden control pages such as the one to customize the dual-color interior ambient lighting as well as the page that updates the custom drive mode, changing everything from the loudness of the engine to the tuning of the engine, steering, and suspension. It’s a great interior in which to spend a commute, and the sport seats with diamond stitching are a huge upgrade in feel and comfort over the base seats in our $52,325 USD A4 long-termer.
One minor issue we noticed in our tester that needs an immediate update if it affects all S4s—the engine stop/start system has a nasty habit of sometimes turning the engine off 1-2 mph (1.6-3.2 km/h) before the car has actually come to a complete stop. I tend to use engine stop/start systems more than the average Motor Trend staffer, but even I turned off the S4’s system on our tester.
After you press the button to turn off the engine stop/start system, you’re left with a well-rounded car, just like the less powerful but still quick A4. The S4 is fun to drive, though it’s not quite as connected to the road as the Cadillac ATS and Jaguar XE. What prevents me from recommending those cars are their rear seats, which are among the most cramped in the class. Then there’s the turbo-four-powered version of the Alfa Romeo Giulia, an entertaining car that lacks a direct S4/C43 competitor. Plus, the all-wheel-drive version of the Italian sedan is more than a second slower to 60 than those cars.
When you want a very quick compact luxury sport sedan instead of a moderately equipped midsizer like everyone else, the C43 presents the biggest threat to the S4. If the S4 is too subtle for you, consider the more showy Mercedes. The Head 2 Head winner will probably be more expensive once you add all the options you want, but it’s attractive and—for better or worse—louder.
If you’re seeking sportiness more than straight-line acceleration, consider the S4 or the C43. But where does that leave the A4’s class-leading acceleration?
I asked online editor Alex Nishimoto his thoughts on the A4/A5 versus S4/S5 question because he reviewed the A5 and S5 Sportback models last year. “Although I could certainly live with the A4’s turbo 2.0-liter,” he said, “if I was splurging on a luxury sport sedan I’d most likely be seduced by the S4’s addictive thrust. The turbocharged V-6 just accelerates effortlessly—even when you punch it at cruising speed—and having that extra fun on tap would be worth the price premium for me.”
For me, as much as I’d miss taking on my favorite driving road in sport seats that massage me (standard on the S4), I wouldn’t get the S4, A4, or even the C43. The A5 Sportback is the car I’d drive. Arguably more beautiful than any car mentioned above, the A5 Sportback would still be quick when you need it but also efficient when you don’t. The car will spend more miles on the road between fill-ups, and even though I’d long for the sound of an S4/S5 or C43 engine, the money I’d save (as much as $5,000 USD or more depending on options) might just make that compromise worth it.
So if you go S4, enjoy the added punch the turbo-six engine provides—you’ll be driving one of the quickest sedans around. Thanks to my thousands of miles in an A4, however, I’d put the A5 Sportback at the top of my list. The turbo-four engine provides plenty of oomph, and the hatchback boasts way more curb appeal than a stylish but subtle A4/S4 will ever have.
|2018 Audi S4|
|PRICE AS TESTED||$65,051|
|VEHICLE LAYOUT||Front-engine, AWD, 4-pass, 4-door sedan|
|ENGINE||3.0L/354-hp/369-lb-ft turbo DOHC 24-valve V-6|
|CURB WEIGHT (F/R DIST)||3,938 lb (57/43%)|
|LENGTH x WIDTH x HEIGHT||186.8 x 72.5 x 55.3 in|
|0-60 MPH||4.2 sec|
|QUARTER MILE||12.8 sec @ 107.5 mph|
|BRAKING, 60-0 MPH||104 ft|
|LATERAL ACCELERATION||0.99 g (avg)|
|MT FIGURE EIGHT||24.3 sec @ 0.82 g (avg)|
|EPA CITY/HWY/COMB FUEL ECON||21/30/24 mpg|
|ENERGY CONS, CITY/HWY||160/112 kW-hrs/100 miles|
|CO2 EMISSIONS, COMB||0.80 lb/mile|