German auto maker Audi has officially launched its latest TCR car, the second-generation RS3 LMS. Visually, the new RS3 differs significantly from its predecessor, with Audi noting the body has been revised to both reflect the current production model and also improve aero performance.
For example, the front apron incorporates the air intakes as part of a significantly revised cooling concept for the engine and brakes, and the rear wing uses a reverse swan-neck support for the first time. Notably, Audi states that the aerodynamic development was conducted solely in CFD, a first for the company, with no wind-tunnel testing performed.
Chris Reinke, head of Audi Sport customer racing, explained, “The focus of our development goals for our latest model was on the customers. Whether it’s about running times or setup options, safety or cockpit ergonomics: we want to offer the teams a car that’s even more of a race car than before, that has many practical advantages in everyday use and that can be operated economically thanks to long-running times.
“Customers all over the world benefit from a comprehensive service network, a reliable supply of parts and the continuous further development of the race car over the course of its model lifecycle.”
Updated production engine
The car features the fourth generation of the 2-liter, four-cylinder EA888 engine. Impressively, the block and cylinder head, crank drive, valvetrain, intake manifold, fuel injection and turbocharger are standard production items. Only the valve cover breather with its oil separator differ from the standard component, as does the exhaust system.
Audi notes that adoption of the engine from volume production has proved highly successful in TCR racing. However, it admits that calibration of the new, spec engine management system from Magneti Marelli required a great deal of development work.
One area subject to considerable revision has been the cooling package. The two main engine heat exchangers, one for charge air the other for engine coolant, arranged horizontally one above the other, are now separate units mounted in vibration-absorbing mounts, making them less sensitive to vertical impacts, such as those experienced when a car runs over the curb.
The transmission has also come in for a revamp. The twin-plate racing clutch now weighs 800g less than in the previous model, reducing rotational mass as well as inertia. Audi also states that mechanics can now adjust the locking effect of the newly developed differential, which features 12 friction surfaces, externally. It also claims that development of stronger driveshafts also contributes to higher mileage and an improved cost balance for competitors.
Further aiding both reliability and maintenance, the new wiring loom features six decentralized fuse boxes, which reduces both weight and cable complexity, while offering targeted redundancy. As a result, any electrical malfunctions in individual subsystems have less impact on the entire network.
According to Audi, revisions to the McPherson strut front suspension make it possible to implement kinematic changes faster than ever before. Whereas the previous car required the removal and refitting of various bolts to change the setup, with careful measurement of the chassis to confirm alterations required, shims can now be inserted in the control arm and track rod in a matter of minutes to alter the geometry.
Four different shims, from 1.2mm to 10mm, can be combined in such a way that camber changes from 2° to 7° at the front axle can be achieved. As these changes can be achieved without having to realign the wheels, Audi says this makes mid-session geometry changes a possibility.
Furthermore, the rear axle now features track rods as standard on the four-link to achieve bump steer effects. Other variables relating to suspension kinematics, such as anti-dive and anti-lift, the height of roll centers and caster, or the distance of the subframes to the body when the ride height is altered, can also be adjusted trackside to refine chassis behavior. Highlighting the drive toward ease of operation, Audi notes that the roll bars are also now equipped with quick release connections.
Finally, though disc diameter and thickness are governed by regulation, braking performance has been improved though ventilation of the six-piston AP Racing calipers, rather than just the disc as was the case on the previous model.