Porsche 934 Turbo RSR | Setup Guide

Discussion in 'Car and Track Knowledge Base' started by Thomas Jansen, Apr 9, 2019.

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  1. Thomas Jansen

    Thomas Jansen Well-Known Member Beta tester

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    [​IMG]
    The second car I chose is another very underrated car, this old Porsche is amazing fun to drive and extremely challenging to drive quickly and consistently. A balanced setup can make a world of difference in taming these kinds of cars, confidence is key. The massive turbo lag on this car also means getting the gear ratios right is crucial for good laptimes. The setup on this car is mostly unlocked, but it is still fairly simple to deal with, as there are no aerodynamics to take into account, which actually makes it a good car to feel the effect of suspension adjustments without other disturbances.

     
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    Last edited: Apr 9, 2019
  2. Thomas Jansen

    Thomas Jansen Well-Known Member Beta tester

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    Red Bull Ring GP

    Setup & Telemetry



    Brake Bias
    The brake bias on this car is a good example of the trade-off you have to make with this setting sometimes. Not all cars have the braking power available to lock the wheels at all times and quite often the rear brakes are weaker than the front brakes. This means that when none of the tires are locking at maximum brake pressure, you can actually lose overall braking power by shifting the brake bias rearward. I felt that this was the case on this car, as I had no problems with the rear under braking with a brake bias as low as 54%. I settled on 57% as the fronts were never locking much for me and it still made the car a bit more agile on the brakes than on default. I think a large range of settings here will work fine, all up to preference!

    Gear Ratios
    Setting up the gear ratios on a car with significant turbo lag such as this Porsche can have a really big effect on laptimes. Both individual gears and the final drive are unlocked on this car, giving you quite a bit of freedom. However, this car only has 4 gears, which can make it quite tricky to make them flow into each other nicely, while being in the turbo range out of all corners. I was quite lucky, as it worked out perfectly on this track, for every corner I have a gear that sits in the turbo range at the exit, while all the gears flow into each other almost exactly the same, making it easy to get used to. I intentionally used one gear higher in turn 3 of my in-lap in my video, to show the impact this has on laptime, this probably cost 1-2 tenths, purely from the extra time it took for the turbo to spool up.

    Tire Pressures
    Telemetry was very helpful for this car, the rear was quite loose on default, especially on the brakes. I could have just pinned this on the old tires and suspension, but the telemetry showed that the rear tires were quite overinflated, with the middle tire temperature being equal to the inside tire temperature all around the lap. On the other end, the front tires were a bit underinflated, causing the front to feel soft and slidy. This could again be pinned on the old nature of the car, but after tuning the tire pressures with some large steps, the handling became much better overall. The rear was more controlled under braking and the front felt much more responsive.

    Camber
    In the setup you set the 'static' camber, which is not really representative of what the value will be on track. Suspension travel and body roll will determine what the actual camber angle of the tire will be as you go through a corner. This car has about -0.5 degrees of camber on the outside tires through fast corners for example, while the static camber is -2.5! Having the outside tires on the optimum camber angle through a corner will give you a slight boost in lateral grip. However, as there is more body roll in fast corners than in slower corners, this will always be a trade-off which depends on the track. Add to that the effect camber can have on longitudinal grip, with smaller camber angles improving braking and traction slightly. The optimum camber angle is not always known, but you can assume that the default camber brings you quite close to this value. As Red Bull Ring is a relatively slow track, with lots of hard braking and traction zones, i reduced the camber slightly and it seemed to work well. You can see the dynamic camber angle in the telemetry too, allowing you to see exactly what the camber is doing through different corners.

    Toe-in/out
    Similarly to the Porsche 911 GT3 Cup, I left the front toe-out on the default value and lowered the rear toe-in slightly to make the car steer a bit more into the corner when going on power. This was mainly to prevent the car from pushing wide when the turbo has not kicked in yet, as the power off-boost is nowhere near enough to get rear slip.

    Anti-Roll Bar
    After tuning the tire pressures, the overall balance of the car was quite understeery, as the grip on the rear tires improved a lot. This meant I had some room to try to get some more grip on the front too by playing with the suspension. The first option I usually go for is softening the front ARB, two clicks down to the minimum value seemed to work well, but there was still some more room to shift the balance frontward. You could try to increase the rear ARB to get a similar effect, or try to change the springs. I chose to try the latter first.

    Springs
    The springs have a very similar effect to the ARBs as they also resist body-roll, however, the springs affect pitch movement as well, which makes them a bit more tricky to deal with. Luckily this car has quite a bit of ground clearance and no real downforce, so I could lower the front springs by one click to get a nice neutral balance through the corners. Make sure to be careful when adjusting the springs though, it might change braking behaviour, ride height, curb absorption, so lots to keep in mind even on a car without downforce.

    Dampers
    The dampers are mainly meant to control suspension movement and weight transfer, stopping the car from bouncing around. They are also essential in absorbing curbs as efficiently as possible. Most modern cars have both slow speed and high speed damper adjustments, the first mainly aimed at controlling the weight transfer and the latter for curb absorption. Unfortunately we only have access to the slow damping in RaceRoom, though on this particular car this is also the only adjustment available on the real thing. @Alex Hodgkinson did an excellent job at tuning these values to keep the car stable over the bumpy surface and curbs on the Red Bull Ring. The weight transfer on the car had some room for improvement, as I felt it would often lose grip on the rear if I was a bit too eager on turn-in. This was potentially caused by the reduction on the front springs. To fix this I lowered the rear rebound by one click to keep the rear wheels in contact with the road a bit better as the weight shifts forward, increasing the front bump could have been another option here. On corner exit, as the weight shifts to the rear, the front felt a bit lazy. To make it a bit more responsive I lowered the front rebound by one click as well, similarly increasing the rear bump could also help here. When adjusting damper values, you should make sure to check if the behaviour over curbs does not get worse, which was not the case here luckily!
     
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