MoTeC, a Journey: Getting The Most From Data Analysis

Thanks!. Another question is, in terms of the damper setup in game, I normally have two situations to deal with:

1. the histogram is kind of flat - in this case, what we should adjust in damper settings? I'm having trouble understanding what's the higher value means for bump and rebound respetively.
2. sometimes, the histogram is ok, but, it will like have slightly more percentage spend in low bump area, or, just the opposite, slightly towards the slow rebound area, how to tune this to make it more symmetric?

besides, a question for 991 car:
3. for 991 GT3 car, I notice on some tracks like Richard, the 991 rear suspension red line (in game setup) is super high, and front red line super low; I kind of get the idea that red line is the bumpstop point, but why designed like this? because it feels that the car will have very short travel distance on front wheel, and very long travel distance at rear wheel, which feels like the car is very 'stiff' at front, but very 'flexble' at rear.

Thanks in advance!

 

Great question! This starts getting into territory that is not so easy even for me, but suffice to say that the outlying factor here is tire flex. Tires do compress and act as a spring in their own right, and that will change the ride height without necessarily appearing in the suspension data. Since we do not know how the sim calculates tire flex, we cannot assume that susp movement = RH movement. And it does/should matter, as even just a mm of adjustment on ride heights can have an effect. That said, it's not entirely incorrect to say that we can't infer something about how much the ride height is changing from the suspension, such as going down the long straights and top speeds and such. It's better than having no data at all.

Come to think of it, a good experiment would be to try different tire pressures and see how that affects top speeds down long straights. That would at least be some indication as to whether the tire behavior has some affect on aero.

 

1. Some histos are flatter than others, primarily because of weight. More weight you put on a damper, flatter it gets. Flat makes it harder to tune since the dampers are spending much more time in the hi-speed range, and are simply moving too fast to be fine tuned. Higher values (peaky histos) just mean that dampers are able to operate in the slow range and you have more leeway in how to adjust them.
2. The more I play around with dampers, the more I get away from the idea that we really want symmetry is the ultimate goal for a GT3 car. We have to remember that at these high speeds with incredible aero packages on the car, the initial goal of dampers - reducing force variation - starts giving way to ride control. What that means is, we want the dampers to control the car's platform at high speeds, and this can sometimes mean we suffer a bit in terms of mechanical grip to help keep the front end of the car down for as long as possible. So if there's a bias towards the bump or rebound - that's fine! Adjust it towards the center if you wish, but I would try adjusting for more bias and see how it feels. The results may be surprising.
3. You see this in all of the cars. Primarily it is because there's more weight up front and thus stiffer springs are needed. However, it's not the only reason. It is again, all about ride control here - get the front end low and ride the bumpstops keeps the front planted in that downward position and reduces any major variations in ride height. A general motto in setting up cars is while you can drive around oversteer, you can't drive around understeer, and having a low front end helps with that. Having such a stiff front end also means that the weight transfer is happening very quickly, so you get a better sense of how the car is handling and can adjust accordingly.

Porsches are especially interesting, just because of how far back the engine is in relation to all other cars. It's kind of a marvel of modern car suspension that porsches even can do what they do. But they are extremely hard to drive because of the lack of weight at the front. But the concept is the same - you have extremely stiff suspension up front to get that weight forward as fast as you can, despite potential lack of grip from doing so.