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In April, we headed down to Silverstone for a BRDC track day where we were working to further develop and enhance the perfect track setup for the 992-generation Porsche 911 GT3RS with the help of RMA Track Days’ MD, Leyton Clarke. We visited Silverstone frequently as part of the development programme of our Porsche GT Circuit Handling Pack, and were eager to use it for the development of our 992 GT3RS geometry and chassis setup.
Silverstone is an excellent circuit with a great mix of corners, which makes it the perfect place to develop a versatile chassis and geometry setup that works in every kind of corner from tight hairpins to ultra high-speed sweepers. Silverstone is also the UK’s only Formula One circuit, so it is maintained to a very high standard with smooth, grippy tarmac throughout.
Leyton’s GT3RS is fitted with the Weissach-package alongside the Suspension Secrets Front Camber Blocks for additional negative camber at the front axle. It was great to see three other 992 GT3RS fitted with the Suspension Secrets Front Camber Blocks, including the JCR Developments 992 GT3RS.
This gave us the unique opportunity to talk about our setup with, and to receive detailed feedback from two accomplished ex-professional GT drivers who were both using their 992 GT3RS’ with our Camber Blocks installed and using the same tyres as each other.
Throughout our testing with the 992 GT3 and GT3RS, we identified the inadequate front axle camber to be the biggest single weakness of the chassis, particularly as the Michelin Pilot Sport Cup 2R tyre and equivalent super-focused track tyres are becoming more widespread. Simply put, the latest GT3 and GT3RS cannot effectively use the maximum performance envelope of these tyres, including the Michelin Cup2 tyre that we were testing on for this day, without being fitted with Suspension Secrets Front Camber Blocks.
The Suspension Secrets Front Camber Blocks are the only solution in the world for increasing the camber angle at the front axle of the 992-generation 911 GT3 and GT3RS without affecting the caster angle. This prevents the tyre from catching the front wheel arch which is a negative side effect of using shims to alter front axle camber.
The latest GT3RS generates far more downforce than any other previous GT3RS and this is another factor that must be taken into consideration when developing a good setup.
With road cars, the downforce figure a car generates at its maximum speed is usually what the marketing departments like to place emphasis on. In the real world, on real circuits, it’s highly unlikely any high-performance car will reach its outright top speed. This makes these figures pretty irrelevant, but it is important to remember that when a car is moving at speed, it is generating downforce. Whilst the figures may not be headline capturing, downforce is still present. This additional aerodynamic grip in mid and high speed corners does play a factor when developing chassis setups, so we paid additional attention to this.
Testing began bright and early with Leyton setting a brisk initial pace. We had previously set the car up at Donington earlier in the year, but this was Leyton’s first time to put the car through its paces.
We were fully equipped for a day of testing, with the car rigged with an AIM data logger which will give us insight into a variety of data streams including G-reading and steering angle. This would give us an insight into where the car was developing grip and if there were any moments of under- or oversteer.
With a few initial laps under his belt, Leyton started to push the car harder so we could find the limitations of grip and begin altering the setup to improve the balance of the car and ultimately unlock even more grip! Initial feedback was that the car was suffering from mid corner understeer quite aggressively through mid and high speed sections of the circuit. The same reports were also coming back from Jonny Cocker of JCR Developments with the exact same symptoms.
Therefore we set to work on the motorsport flat patch and increased front camber further using our Suspension Secrets 992 GT3RS Camber Blocks. With camber increased we also introduced some toe out to the front axle. With Leyton’s car being mainly a track car, toe out is beneficial to improve turn in and help to hook up the front end towards the apex of the corner. The increase in camber is the main solution to solving the mid corner understeer as this provides the contact patch available for the car to lean onto at the apex, determining how much grip is physically available from the tyre at this point.
On a slightly different note, all the 992-generation 911 GT3RS’ present at Silverstone on the day were experiencing issues with their active DRS systems. The cause of these issues was not a software bug, as initially thought, but instead was actually an unannounced over-the-air software update by Porsche which altered the function of the active DRS system for the 992 GT3RS.
With the alterations made Leyton headed out for his third session where we worked to check tyre pressures and temperatures. The tyre pyrometer showed that our camber settings were working perfectly and Leyton was pleased with how the car was driving with the mid corner understeer significantly reduced.
After the alignment and geometry was finalised, we then focused on the features of the 992 GT3RS’ dynamics that can be controlled by the driver: the electronically-controlled differential and dampers. We were keen to fine-tune the differential characteristics, as differentials can play a huge part in how a car tackles a corner from corner-entry, through the mid-corner phase and onto the corner-exit.
Our primary objective was to reduce the mid-corner understeer Leyton had been experiencing earlier in the day. The coast and power settings of the 992 GT3RS’ differential can be adjusted independently of one another. Reducing the amount by which the differential locks when the throttle is closed allows for the rear wheels to rotate at different speeds, which can help to prevent understeer. Reducing the coast settings by two clicks on Leyton’s GT3RS helped to reduce the mid-corner understeer he had been experiencing earlier in the day.
After finalising the coast settings for the differential, we then turned our attention to the differential’s power settings. A differential’s power determines how much the differential locks when the power is applied and the car accelerates. If tweaked correctly, differential power settings can be used to improve corner-exit traction and to help maximise the rear-engine weight bias that already gives the 911 great traction. After a bit of fine-tuning, we settled on a differential power setting, 2 clicks above zero, that Leyton thought was the most confidence-inspiring.
All that was left at this stage was to tweak the damper settings. The characteristics of the dampers on the 992 GT3 RS can be electronically controlled when in Race Mode. Using rotary dials on the steering wheel, the compression and rebound characteristics can be tweaked independently across the front and rear axles. In terms of setup, this gives the final level of control over how a car handles. Dampers affect how a car enters and exits a corner, as well as the car’s stability over bumps and uneven tarmac. With Leyton’s input we quickly found a damper setup that worked perfectly on Silverstone’s wide and smooth tarmac.
At the end of the day testing, we were very happy with the outcome and the final setup on the car, being a combination of hardware upgrades, geometry and suspension setup and damper/differential settings with the car extremely stable, planted and fast.
If you would like to learn more about our suspension setup services or check out our Camber Blocks via the link below. Feel free to get in touch with a member of our team to discuss your requirements and see how we can help.
