Eliminating the Dreaded Audi RS Understeer – Part 3

In this final part of our mission to eliminate the dreaded understeer that plagues our C6-generation Audi RS6, we’ll explore how our Audi now handles after having the suspension overhauled in the workshop.

If you missed Part 2 of this series, we overhauled our RS6’s tired suspension and suspension bushes. We improved the RS6 by carrying out the following:

  • Installation of KW V3 2-Way Adjustable Coilovers
  • Installation of SuperPro Camber and Caster Front Control Arm Bushes
  • Full Corner Weighting and Geometry Alignment Setup

With upgrades installed and the setup finalised, the only thing to do was to give the new-and-improved RS6 a thorough shakedown.

Our RS6 now stands as a shining example of how a few well-judged tweaks can transform a car. 

The RS6 is now a completely different beast. The horrible multi-phase understeer that we documented in Part 1 of this series is gone; as is the clever, but out-of-its-depth EDC suspension system. Instead our RS6 handles with much more grip and adjustability, taking a nice neutral stance when cornering, and even oversteering into and out of some tighter corners.

Compare this to the nose-heavy and unresponsive handling prior to the upgrades and the difference is night-and-day. When driving fast, the RS6 now takes a neutral stance when cornering, allowing you to modulate cornering speed and approach far more easily compared with the car when it was unmodified.

There is no doubt, upgrading the hardware on our RS6 has improved how the car drives. The changes in the front suspension geometry thanks to the offset bushes, and the upgraded KW coilovers have greatly improved how the RS6 drives. Good quality upgrades do bring results, but having the knowledge to make best use of them is more important than the upgrades themselves.

Take the KW V3 coilovers that are now fitted to our C6 RS6 – they are of a far superior quality compared to the standard Audi DRC dampers that the C6 RS6 was supplied with initially, but the adjustment they offer is what really makes a difference.

Using a combination of setup changes, such as setting the rake angle, and damper valving tweaks, we were able to make our RS6 have the capability of achieving lift-off oversteer in tighter corners. 

Rake angle (the difference in ride height front and rear) helps to improve turn-in, as the nose of the Audi is already loaded into the corners. This leaves the suspension free to generate grip as opposed to having to first control the forward weight transfer of the car as the brakes are applied.

Using the independent bump and rebound adjusters on the KW V3 coilovers we were able to modify the handling characteristics of our RS6. By setting the rear bump and rebound to a stiffer setting than the front, it is possible to help the rear axle of the RS6 rotate into slower corners increasing agility.

Considering the nose of the RS6 would have previously just ploughed forwards, this new-found adjustability and neutral chassis behaviour was far more enjoyable and more capable too.

The change to a proper coilover design also served as a good illustration of the difference in style of operation between the original Audi DRC system and the KW V3 coilover. 

The Audi DRC system utilises the electronically adjustable dampers to control the body movement of the C6 RS6. The selectable damper modes are designed to make the damper seem more influential over the ride of the car. The Audi springs are too soft, making the damper feel like it is contributing more to overall ride control. This is an unfortunate bad habit of car manufacturers: relying on the dampers to regulate body control. 

Compare this to the KW where the spring does most of the work, and the damper instead controls the movement and operation of the spring as a damper should. In this more effective setup, the damper controls the movement of the spring, and the spring is responsible for ride comfort and road handling, making the car far more capable over rough roads and when driving quickly.

After the upgrades and the setup, we only encountered understeer once. This was when accelerating out of a tight uphill corner, the front tyres unloaded as the mass of the RS6 moved backwards, which caused the unloaded front tyres to scrabble for grip momentarily. Considering this, a challenging situation – dynamically-speaking – was the only time our upgraded RS6 slightly faltered, was very, very impressive.

With all of the suspension components installed we were able to give the RS6 our full fast road suspension setup. With the addition of the Superpro caster/camber bushes at the front we were able to increase front caster by 2 degrees. Increasing the caster not only improved steering stability but it also increased the dynamic camber gain of the front wheels. This means that as the front wheel are turned through the corner, the outside wheel gains negative camber, further increasing front end grip as the car loads up into the corner. This dynamic benefit massively reduces the understeer through the mid corner section.  The benefits of our highly developed fast road geometry settings were very apparent. The changes to the camber and toe improved how our RS6 drove in every situation. Our bespoke toe angle settings increase the responsiveness of the steering whilst also improving rear axle traction, and the changes we made to camber and caster help to reduce that notorious Audi understeer, whilst also improving front axle grip and steering feel. The increase in static negative camber at the front and rear axles also increased the overall cornering grip of the chassis, providing a much flatter contact patch for the car to roll onto as it loads up on the firmer springs. 

If you’d like to eliminate the understeer on your Audi, or are just looking to improve how your car drives, then get in touch!

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