How do I go about generating maximum downforce?
Maximum downforce is generated when both front and rear downforce has been optimized. Front downforce increases as the ride height of the nose decreases. Basically, the lower the nose the more front downforce. You also have fenders on the front of the car. More fender flare equals more front downforce. Rear downforce is partially related to front downforce as well as having its own aspects. To maximize rear downforce, you want to keep the rear of the car (ie spoiler) as high as possible. A rear spoiler that is higher will catch more air and thus generate more rear downforce.
To sum it all up, the most total downforce is generated when the nose or front of the car is as low as possible while the spoiler or rear of the car is as high as possible (within reason).
Once you enter the garage with that statement in mind, the various options available to you take on a whole new meaning. The general design of the aerodynamic setup include soft front springs combined with a large front anti-roll/sway bar to keep the front end low in the corners. The rear springs will be generally much stiffer than the front springs in order to keep the spoiler up when cornering. This type of setup is used almost exclusively on the Cup circuit today. Try to find the balance between front and rear downforce as this is where the car will handle best.
While every track requires its own setup, similar types of tracks share certain spring ranges for the front and rear. In general, tracks with less banking (ie less than 18-20 degrees) will use front springs in the 450-550 range while tracks with more banking will use springs at 600 or above. As always, there will be variations to this but this should serve as a starting point. Rear springs are generally above 800 with an aerodynamic setup. Springs of this strength and above help to keep the spoiler up in the corners in order to maintain rear downforce and stabilize the car. While the general minimum for rear springs is around 800 lbs, it is not out of the ordinary to see rear springs of 1200 lbs. Again, it all goes back to driver preference and aerodynamic balance so experiment quite a bit to see what works best for you.
At this point I want to explain a bit more about how and why the Motec program can be so useful. The Motec program records and displays (among many other things) the ride heights of the left front, right front, left rear, and right rear at every point around the track (ie dynamic ride height). On every track except the super speedways where restrictor plates are used you will want to focus on the heights in the corners as this is where downforce is most critical. Specifically, you will want to focus on three major sections of the corner which are entry, middle, and exit. As we talked about a little earlier, you will want both the left front and right front ride heights to be as low as possible. Try to get these as close to zero as possible without bottoming out the car as this can disrupt the car. Once you get both front corners of the car at or below 0.5 inches you are getting close. For the rear of the car, optimum downforce occurs when you keep both the left and right rear above 4.5-5.0 inches (dynamic ride heights) when possible. The right rear will generally be higher than left rear so the average height of the two rear corners should be in the 5.0 inch range. Of course, these ranges for the front and rear are considered optimal for downforce and may not be desired in all circumstances and at all tracks. Also, keep in mind that the dynamic ride heights can vary quite a bit from the ride heights chosen in the garage.
