Normal range for the front springs are 500 – 1000 lbs, in 25 lb increments
As well as helping to set the ride height and rake, springs help with mitigating body roll along with the shocks and ARBs. Stiffer springs make for more responsive handling with softer springs helping with grip.
A lot of fine-tuning is done with the bump and rebound of the shocks on the circuit and teams spend a lot of time with it. What they have that we don’t is telemetry showing where the tires are losing traction.
I have some base bump and rebound settings that feel pretty good. I’ll work on the track, turning laps and looking for things that can be helped. A good example of this is there is a large bump at the top of the rise at Road Atlanta before the downhill to the start / finish line. I was finding the rear jumping out at me, so I have stiffened the rebound to slow down the speed at which the shock comes back. This has the added benefit of helping with hitting the curbs, which are a good way to pick up time at Road Atlanta.
We don’t get a front roll center adjustment on the iRacing version of the FG01, however working with all the front geometry to get a good feel is important.
Anti Roll Bars
The front Anti Roll Bar ties the front wheels together and controls how the wheels work together through the turns. Both the front and rear ARB’s are adjustable in cockpit. I like to feel what the front is doing, which means I run a softer front that some. A stiffer front ARB will help when changing direction and initial turn in.
The V8′s run a lot of camber, especially at the front. The default starting point is -6.0. This helps front grip at turn in and through the corners at the expense of stopping distance under braking. I tend to try and get tire temps fairly even across the tires, depending on the track. At silverstone, the long straights give the outer edges time to cool, so tire temps tend to be a little off here. You still need a lot of camber to help through the corners, and the lack of big braking areas mean you aren’t sacrificing too much in braking distance.
Caster effects the twisting of the chassis as the wheel is turned. Caster rotates the front geometry as the wheel is turned. More caster helps with turning the car at the expense of rear grip. I try to balance the caster with the Watts linkage at the rear to help the car turn through different turns at a track. Silverstone was a good example here as a lot of caster helped the car through the slow corners while letting me run a lower rear Watts linkage that gave better high speed grip at the rear for the fast right hand corners.
At Road Atlanta, there are more medium speed corners that could use more rear roll center/ higher Watts Linkage, so I reduced the caster so maintain balance through the turns.
Toe In/ Out
Toe In – helps with straight-line stability
Toe out – helps with initial turn in
While a little is good, more is not always better. Excessive toe in/ out will greatly affect tire wear.
Rear Springs 200 – 500
Roll Center/ Watts Linkage
Lower reduced body roll – more traction
Higher increased body roll – better turning
limit body roll tries to torque the bar when turning
Rear camber is usually around -2.0 although I have seen much more camber used on setups. More camber on the rear will help get the car through the corners however it can lead to increased tire wear, reduced straight line grip and reduced stopping distances with the rears locking up easier due to reduced grip.
Front ride height is generally around 3″, much lower than this causes the splitter to hit the ground under heavy braking.
Rear ride height is usually 1 – 1.5″ higher than rear to help the car turn.
Higher ride heights will generate more body roll.
To adjust the ride height adjust spring perch at each corner.
A lot of setups have uneven ride heights right to left due to the live axle moving the chassis under acceleration. Generally a little more right side weight to counter balance the torque going through the drive train.
Rake is the difference in ride heights front relative to rear. More rake (bigger difference between rear and front ride height) = looser car, Less rake = more understeer. The key is trying to balance the car and be able to control balance during the fuel burn by using the front and rear anti-roll bars.
Due to the heavy nature of the car and the relatively soft rear springs used, rake will increase as fuel burns off. These cars carry around 38g/ 120l fully loaded which is a lot of weight to shift through a fuel run.
This means that the Falcon tends to get looser through the run, especially when combined with rear tire wear.
Tire acts a spring, with softer tires generally offering increased grip. The aim is to have even tire temperatures across the tires, although this is somewhat dependent on the type of track. A track with a lot of straights, compared to corners will see the outer edges cooling between corners even though the corner grip is correct.
Aim for around 200 f across the tires for optimum grip.
Locking up the rears usually leads to a quick swapping of ends and the air being filled with expletives. While a rearward bias will help you turn the car getting into the corner, too much will lead to bad things. Something to also take into consideration is that as fuel burns off the rear of the car will have less stopping power and it’s a good idea to creep the bias forward as the race progresses.
Ford Falcon FG01 is a big, heavy under tired sedan. With a live rear axle and lots of power it rewards a certain driving style.
Back the corners up; get it stopped in a straight line before turning in. The live rear end tends to push on corner entry so getting it slowed down before turn in is vital in saving the front tires.
Roll the car through the corners feeding the power on gently, again the nature of the live axle is to be tail happy on corner exit, this requires a gentle application of power after the apex and full noise applied once the car is pointed down the next straight.
The rake tends to increase as the fuel burns off which leads to more over steer through the run. This can be countered by lowering the rear ARB as the race goes on. I tend to lower the rear ARB by 1 click every 6 laps or so depending on how bad the rear tires are being abused. The front ARB also can be stiffened as the run goes although I tend to start it at 5 and lowered it to 4 as the front tires lose their initial grip.