Last month or so I stumbled across a conversation about ride height and using Motec to find out if the car is bottoming out. I'm not real good at understanding what Motec is telling me, but a couple of nights ago I looked at Motec for the Formula E Gen 2 cars that I drive mostly. Even with the default front/back 2.5/4.5 setting, Motec was telling me that at the end of the long straights at New York the back was lower than the front. I'm inclined to think that's bad because that should mean the car is lifting off the track like an airplane wing. First off, is Motec accurate for ride height? If so, what's the customary way to fix? Raise rear ride height? Lower front? Do both? Stiffen rear springs? Add packers? Stiffen rear roll? I'm a long way away from being an engineer or mechanic. I also read that any ride height result on the graph that is less than 20mm or so is too low.
Rear downforce is greater than front downforce, although real FE cars don't really have that much downforce to begin with; don't know how its modeled though. Packers are a good starting point as well as rear ride height. Stiffer springs will help if those two don't solve it. ARB's won't impact ride height, but can be used to balance the car front/rear. So if you add stiffer springs to the rear you may want to reduce Rear ARB or stiffen Front ARB to balance the spring change. Every car is a little different but typically follow that process. Lowering the car doesn't just affect the Center of Mass, it also affects the suspension geometry. Dampers don't impact ride height either, they merely slow the motion down.
MoTeC shows the ride height at the undertray and I believe the ride height in the setup is at the axle (please correct me if I'm wrong on the latter). Ride height data from MoTeC should be accurate, but it also depends on which logging rate you have set. Whether a negative rake angle is good or bad can only be determined by looking at the data, or obviously doing trial and error by feel/lap time. Personally, I wouldn't necessarily say that a negative rake angle on the straight is a bad thing since it will likely cause a stall in the diffuser and reduce downforce/drag, something you don't really need on a straight. Many teams in F1 do the same by stalling the diffuser (or at least reducing the downforce/drag) on the straights by running a collapsible heave system. Then again, I've never really had much success by doing this in the game. If you want to achieve a positive rake angle through setup I'd look at the front ride height first. If you can go lower, go as low as possible until you feel it's detrimental to your lap time. It rarely is, but if the car is pitch sensitive you might have to change the mechanical balance a bit to counteract the grip change. In general, you gain downforce and drag the lower your front is, but much more of the former. Some cars may have an aggressive stall of the diffuser or the front wing, but you will notice it fast through the change in balance. You also don't have to take plank wear / underfloor damage into account by running dangerously low, so there are not many downsides in going as low as possible. If you have a vertical spring/packers available I'd look at that. It has much less effect on balance compared to changing the stiffness of the corner spring, so a win-win component. If the car doesn't have a vertical spring, raising the rear ride height would likely be my alternative option. +5 mm would be a good first increase, get a feel for the balance change and look at data. Though, if your car lacks downforce it's usually best to run the static ride heights as low as possible. From personal experience, having an increase in downforce is worth less than a lower CoG in cars that are not solely dependant on aerodynamics. Corner packers can also work since it allows you to still run low ride heights and soft springs whilst maintaining ground clearance. The big downside is obviously that the extra stiffness will affect both vertical and roll stiffness, meaning a much greater effect on balance compared to the vertical packers that only change the vertical stiffness. Those are some options you can check, hope they are of any help. With the lack of data available you are kind of tied to trial and error. It's hard in the beginning, but the more you play, the more you learn, and you start to find patterns of what can be abused in the game.
