The 2021 Audi S4 generates 349 horsepower and 369 lb-ft of torque from its turbocharged 3.0-liter V6 engine, accelerating from 0 to 60 mph in 4.4 seconds. This performance profile represents a specific evolutionary milestone in the B9.5 generation of Audi’s compact executive sports sedan, balancing forced-induction efficiency with quattro all-wheel-drive dynamics.
Introduction to the 2021 Audi S4 and the B9 Generation
When evaluating luxury sport sedans, few nameplates carry the historical consistency and technical evolution of the Audi S4. Positioned squarely between the standard Audi A4 and the high-performance Audi RS 4 (which is not offered in North America), the S4 has long served as the benchmark for everyday usability combined with track-capable capability. To understand the 2021 audi s4 horsepower and performance timeline, one must look closely at the B9 platform iteration—specifically the mid-cycle refresh known internally as the B9.5 generation.
The 2021 model year sits at a crucial juncture where internal combustion engines reached a high level of refinement before the integration of more aggressive hybridization. Dissecting this vehicle requires analyzing its powertrain architecture, real-world track and street performance metrics, how it compares to its immediate predecessors and successors, and the mechanical nuances that define its driving character.
Powertrain Architecture: The 3.0L TFSI V6 Engine
At the heart of the 2021 Audi S4 lies a turbocharged 3.0-liter EA839 V6 engine. Unlike earlier generations of the S4—such as the B8 generation, which utilized a 3.0-liter supercharged V6—the B9 and B9.5 architectures rely on a hot-V turbocharger configuration. This means the twin-scroll turbocharger is nestled inside the "V" of the cylinder block, shortening the exhaust path to minimize turbo lag and optimize throttle response.
The engine produces an official factory output of 349 horsepower (available from 5,400 to 6,400 rpm) and 369 lb-ft of torque (available across a remarkably broad band from 1,370 to 4,500 rpm). This wide torque band is critical to the car's performance timeline; peak twist is accessible almost immediately off idle, providing effortless low-end grunt for passing maneuvers and aggressive corner exits.
Transmission and Drivetrain Integration
Power is channeled through an 8-speed Tiptronic automatic transmission supplied by ZF. Unlike the 7-speed dual-clutch S-tronic transmission found in earlier B9 models (2018–2019), the 8-speed torque-converter automatic was chosen for its ability to handle higher torque loads while delivering smoother creep behavior in heavy urban traffic.
The drivetrain utilizes Audi’s legendary quattro permanent all-wheel-drive system, featuring a self-locking center differential. Under normal driving conditions, power is split 40:60 front-to-rear, lending the S4 a rear-biased driving dynamic that mitigates the understeer traditionally associated with front-heavy, all-wheel-drive platforms. When slip is detected, the system can dynamically route up to 70% of torque to the front axle or up to 85% to the rear axle.
Comprehensive Performance Metrics
Numbers on a spec sheet only tell part of the story. The 2021 Audi S4 translates its 349 horsepower into concrete, repeatable performance figures that place it firmly in the crosshairs of the BMW M340i and Mercedes-AMG C 43.
- 0 to 60 mph Acceleration: 4.4 seconds
- Quarter-Mile Sprint: Approximately 12.9 to 13.1 seconds at around 105–107 mph
- Top Track Speed: 155 mph (electronically limited)
- Braking (70 to 0 mph): Approximately 151 feet (equipped with optional sport brakes)
- Lateral Acceleration: ~0.95 g on a 300-foot skidpad
Real-World Driving Dynamics
The chassis of the 2021 S4 relies on a five-link front and rear suspension layout. Buyers could choose between the standard sport suspension, a sport-tuned adaptive damping suspension, or the S Sport package—which adds a sport adaptive damping system alongside a quattro sport rear differential.
The quattro sport rear differential is a torque-vectoring unit that can actively distribute torque between the rear wheels, physically rotating the car into a corner rather than relying solely on brake-based torque vectoring. This hardware addition fundamentally transforms the car's agility on technical backroads.
The Performance Timeline: Contextualizing the 2021 Model
To fully appreciate the 2021 Audi S4, it must be viewed within the broader historical timeline of the S4 lineage and its immediate surrounding model years. The transition from the supercharged era to the turbocharged era marked a shift in how power is delivered and modified.
| Model Years | Engine Type | Horsepower | Torque | Transmission | Key Performance Milestone |
|---|---|---|---|---|---|
| 2010–2016 (B8/B8.5) | 3.0L Supercharged V6 | 333 hp | 325 lb-ft | 6-speed Manual / 7-speed S-tronic | Instantaneous supercharger throttle response; widespread enthusiast adoption. |
| 2018–2019 (B9) | 3.0L Turbocharged V6 | 349 hp | 369 lb-ft | 7-speed S-tronic | Introduction of the EA839 hot-V turbo engine; dual-clutch transmission. |
| 2020–2023 (B9.5) | 3.0L Turbocharged V6 | 349 hp | 369 lb-ft | 8-speed Tiptronic | Facelift update, MIB3 touchscreen infotainment, switch to 8-speed ZF automatic. |
| 2024–Present | 3.0L Turbocharged V6 | 349 hp | 369 lb-ft | 8-speed Tiptronic | Final iterations of the internal combustion S4 before electrification shifts. |
The B9 to B9.5 Facelift Transition
The 2020 model year introduced the B9.5 facelift, which carried directly into 2021. While horsepower and torque figures remained identical to the 2018–2019 pre-facelift models, the vehicle received updated exterior styling—including sharper LED matrix headlights, a wider single-frame grille, and pronounced blister fenders reminiscent of the original Audi Quattro.
Inside, the rotary MMI controller was removed in favor of a 10.1-inch touchscreen running Audi’s third-generation MIB3 infotainment system. From a pure performance timeline perspective, 2021 represents the sweet spot of the B9.5 generation: it retained the mechanical purity of the pure ICE V6 powertrain before strict global emissions regulations prompted mild-hybrid and heavy particulate filter (GPF) additions in international markets.
Tuning Potential and Aftermarket Performance
One of the defining characteristics of the EA839 3.0L V6 engine is its robust thermal headroom and strong internal components, making it a favorite within the enthusiast tuning community. While the factory 349 horsepower is ample for daily driving, the engine responds exceptionally well to ECU software calibration.
- Stage 1 ECU Tune (Stock Hardware): Upgrading software alone via reputable aftermarket tuners can push output from 349 hp to over 420–440 hp and torque to nearly 480 lb-ft on standard pump gas, reducing the 0–60 mph time into the high 3-second range.
- Stage 2 Upgrades: Adding an upgraded intercooler, cold air intake, and high-flow downpipe allows output to exceed 460+ hp, unlocking sustained high-RPM power delivery suitable for track-day enthusiasts.
However, owners exploring aftermarket modifications must account for drivetrain stress, particularly regarding the limits of the factory turbocharger and the thermal management capacities of the cooling system during extended track sessions.
Frequently Asked Questions
Does the 2021 Audi S4 have a manual transmission?
No. Manual transmission options for the Audi S4 were discontinued globally after the B8.5 generation concluded in 2016. The 2021 Audi S4 is exclusively equipped with an 8-speed ZF Tiptronic automatic transmission.
Is the 2021 Audi S4 faster than the BMW M340i?
In stock form, straight-line performance between the 2021 Audi S4 and the BMW M340i (G20 generation) is remarkably close. The BMW M340i features a slightly more powerful inline-six engine (382 hp) and typically edges out the S4 in a standard 0–60 mph sprint (roughly 3.8 to 4.1 seconds), whereas the S4 relies heavily on its quattro all-wheel-drive launch consistency in adverse weather conditions.
What is the difference between the S Sport package and the standard suspension?
The S Sport package adds three critical performance components: a sport adaptive damping suspension, red brake calipers, and—most importantly—the quattro sport rear differential. This differential actively vectors torque between the rear wheels to eliminate understeer, making it a mandatory option for driving enthusiasts.
What fuel economy does the 2021 Audi S4 achieve?
According to EPA estimates, the 2021 Audi S4 achieves an efficiency rating of 20 mpg in the city, 28 mpg on the highway, and 23 mpg combined. Real-world fuel economy heavily depends on driving style, but the 8-speed automatic's tall eighth gear allows for efficient long-distance highway cruising.
Are there any common reliability concerns with the 2021 Audi S4 engine?
The EA839 V6 is generally considered robust and reliable when properly maintained. Early B9 models (2018–2019) occasionally experienced rocker arm wear issues in very early production runs, but Audi updated the component metallurgy by the 2020–2021 model years, making the B9.5 generation significantly more reliable.
Conclusion and Buying Recommendation
The 2021 Audi S4 stands as a refined, highly capable sports sedan that bridges the gap between raw track performance and executive daily comfort. Its 349-horsepower turbocharged V6, combined with the sophisticated quattro all-wheel-drive system and the ZF 8-speed automatic transmission, delivers a bulletproof daily driving experience across all weather conditions. For buyers seeking a modern performance sedan without the harsher ride quality or aggressive styling of higher-tier sports cars, the 2021 model remains a premier choice within its historical timeline.
