Setup confusion: third spring, lateral ...

Christian Lyngbye · May 28, 2012

RFactor 2 has some new setup features or I just haven't seen them in RFactor 1. I'm a little confused about some of the concepts even though I found some explanations here:
http://forum.racingtracks.net/index.php/topic,630.0.html

Correct me if I'm wrong about some of this

Third spring - I see this on the open wheelers (FR3.5 and FMasters) and I guess this is a like a combination of regular front and rear springs so the adjustments should work the same way?
Lateral weight distribution - why would you want to switch weight laterally unless you're driving an oval?
Engine brake map - This is explained elsewhere and apparently it's a way to keep the throttle on when you're braking (eliminating the need for heel-toe).
Fuel consumption - This is represented in kg's in the FMasters, WTF? and most of the time this is off by 200% according to my experience so I hope ISI give us an ingame approximator or something.

Knut Omdal Tveito · May 28, 2012

I'll give you my experience on these points.

Third spring. This is a suspension configuration that applies to high-downforce cars especially with undertray/diffusers. When you have a car with high downforce you need a high spring-rate to maintain the rideheight of the car at high speeds. This has a tradeoff by compromising the handling in corners. The solution is to use three springs. In the picture below you can see the two normal springs connected to the pushrod through the bellcrank. but there is now an additional spring connected by a rocker arm in the middle. When both the left and right wheels are pushed upwards, you also compress the third spring so the effective spring rate is increased by the 3rd spring. However, in a corner when the left and right wheel move in opposite direction, this does not compress the 3rd spring significantly. Thus you get a higher effective spring rate in the straight line, with less trade-off in corners. It is very useful to maintain good handling and also good aerodynamic stability at high speed (prevent choking the diffuser etc).

Lateral weight distribution. Used in ovals as you said, but also in circuits where the left and right tires are worked very differently, i.e. when there are more right-hand than left-hand corners. Same reason to use asymmetric setups.
Engine brake map. Adjust how much engine braking when off throttle. Engine braking is very useful to take some load off the disc-brakes (and you can then run less duct size with less drag). But with too much engine braking it will be difficult to keep the rear of the car stable during braking.
Fuel consumption. Not sure about this one.