The Audi S4 is known for its performance and handling, but upgrading to a Limited Slip Differential (LSD) can significantly enhance both. This article explores the benefits of an LSD compared to the standard open differential and the optional Sport Differential found in some S4 models.
Open Differential vs. Limited Slip Differential (LSD)
The standard “open differential” in an Audi S4 has a critical drawback: when one wheel loses traction, all the engine’s torque is directed to that wheel, hindering performance. This results in poor handling on slick surfaces like snow or ice, reduced acceleration off the line, and compromised cornering ability.
An LSD addresses these shortcomings by distributing torque between both wheels, even when one has limited grip. This translates to several key advantages:
- Improved Acceleration: Launch off the line quicker and with minimal wheel spin. The LSD ensures power is sent to the wheel with the most traction, maximizing acceleration.
- Enhanced Cornering: Apply more power when exiting corners, as torque is distributed to match the available traction of each wheel. This eliminates the frustrating experience of the inside rear wheel spinning, allowing for more controlled and confident cornering.
- Seamless Drivability: An LSD doesn’t introduce any noticeable noise, vibration, or harshness (NVH). Its purely mechanical operation ensures a refined driving experience, seamlessly integrating with the S4’s existing characteristics. It’s a true OEM+ upgrade.
- Increased Strength: The helical gear design of a typical aftermarket LSD is inherently stronger than the standard open differential’s two-pinion spider gear system, offering enhanced durability and reliability.
LSD vs. Audi S4 Sport Differential
While the Sport Differential is marketed as a performance upgrade, it has limitations compared to a traditional LSD. The Sport Differential is essentially an open differential with a clutch-pack-driven override system that can apply additional torque to the outside wheel during cornering. This design, however, presents some weaknesses:
- Open Differential Behavior: Because the Sport Differential relies on an open diff core to function in conjunction with its torque vectoring system, it behaves like a standard open differential in low traction situations or when a wheel lifts mid-corner. This can lead to inside tire wear and reduced performance in challenging conditions.
- Durability Concerns: The Sport Differential has known weak points, including the casing attachment points, spider gears, and clutch packs. These components can be prone to failure under stress, potentially leading to costly repairs. Additionally, the system’s reliance on a pump, sensors, and a control module introduces more points of failure compared to the simpler mechanical LSD.
Conclusion
For Audi S4 owners seeking a substantial performance upgrade, a traditional LSD offers a compelling alternative to both the standard open differential and the Sport Differential. Its ability to consistently distribute torque, combined with its inherent strength and seamless integration, makes it a valuable enhancement for both daily driving and spirited performance. An LSD provides predictable and reliable performance in all conditions, enhancing the S4’s already impressive driving dynamics.
