Porsche 997 GT3 Improved Handling
Having received critical acclaim with our chassis development on supercar and sports marques such as Aston Martin, Ferrari, Lamborghini, Bentley, Jaguar, Honda etc, we are always interested in turining our expertise to new and interesting challenges!
A client brought his immaculate Porsche 997 GT3 to us with a report of unbalanced handling and the usual characteristic understeer, in order for us to review and to recitfy.
When initially presented to us this car’s driver was encouraged to describe the chassis’s handling characteristics in his own words, the aim here is to try to identify the basic nature of the main issues directly from the end users viewpoint. At this point we also attempt to gauge the priorities that the driver is intuitively attributing to the various aspects of the chassis’s handling. Accurately deciphering what chassis characteristics a driver is truly looking for is absolutely key in this chassis “tuning” process, and quite often is more difficult to get right first time than actually generating the desired handling traits.
In this particular case our client was describing four major complaints,
- Firstly a very early onset front first departure (under-steer)
- Secondly a cyclic loading and unloading of the rear tyre during “out of corner” traction events
- Thirdly the steering wheel position was off to one side when the chassis was driving straight ahead
- Fourth was a simply a general description of the chassis inability to inspire driver confidence
The next step was to take a test drive ourselves; we deliberately do this before we carry out any chassis measurements so as to gauge the chassis’s performance as fairly as possible without pre-judgement.
In this case our test drive correlated 100% with the owner’s complaints; the onset of the front axle departure was very early indeed and almost impossible to avoid, this gave the driver a very strong feeling of a lack of directional control.
The chassis was then inspected and the suspension geometry accurately measured. This initial measurement immediately highlighted some serious problems with large imbalances in the geometry on every corner of the chassis.
Front characteristics:
- Patter
- Massive under steer regardless of balance (throttle/brake)
Rear characteristics:
- Too stable, large centreline forces
Overall geometry during this initial test:
Left Right
Front Caster 7’20 7’31
Front Camber -1’05 -0’52
Front Toe 0’25 -0’12
Rear Camber -1’26 -1’31
Rear Toe 0’11 0’25
After ensuring that the cars ride heights and tyre pressures where accurately set, our next step was to build a basic but perfectly symetrical chassis geometry set-up and head out for another test drive.
The problem with the steering wheel misalignment, and the problem of the cyclic “loading then unloading” of the rear tyres during traction events were cured straight away, but the problem of the very early “front first” departure was still a predominant issue and therefore the chassis was still unable to inspire any real driver confidence.
With the car once again fitted inside our suspension alignment jig, an extensive investigation was conducted in order to better understand the changes that are affected dynamically to the cars suspension geometry as the car enters and departs corners. We were able to find several different methods of altering the geometry in a way which would help the front axle generate more mechanical grip under these dynamic loadings and therefore delay the onset of this troublesome “front first departure” or in driver speak; “cure the understeer”.
Once we had a model of how the suspension geometry was effected by our chassis pitching and rolling we were able to run through a series of static geometry iterations, each one followed up by real world testing. After running though five separate geometry iterations we had locked on to a set of static geometry targets which gave us the dynamic traits we were looking for. At this point we ran a series of further tests in order to arrive at the perfect balance in antiroll bar rates and then the perfect tyre pressures which would give the chassis tuning the final polish.
The customer feedback was immediately positive; “awesome, I can’t believe just how different it feels”
Please see and order our stage 1 FRS geometry optimisation at Porsche 997 GT3 dynamic handling upgrade
We’re also offering other handling packages such as springs, dampers, anti-roll bars and complete kits, which can be seen at Porsche 977 GT3 further handling improvements
As an aside, we’re about to embark on a programme of analysing and improving the dynamic performance characteristics of many other Porsche models.