Setting up a Nascar
Before reading this, you should read and be familiar with the descriptions of the setup options and their effects on your NR2003 car, that are contained in the game manual. What I'm presenting you here is an overwiew of how the setup of a Winston Cup race car is managed as a system. This is written from the standpoint of how the real hardware is managed; the game developers at Papyrus and I have done a considerable amount of work to make your NR2003 car replicate, as accurately as possible, the performance of the real thing. The following are general principles - sometimes, unique issues of track geometry will require some deviation from these principles.
A NASCAR Winston Cup race car is a 3600-lb combination of man and machine trying to get around turns fast. What makes it tick? Let's start by first considering what to do with the 3600 lb. Where should it go? Let's consider some general issues in cornering through comparing some corners:
At Bristol or Martinsville, the car rounds a 180-degree corner in 5-6 seconds of time. At Rockingham, it turns 160 or so degrees in 9 or so seconds. At Charlotte or Michigan, it turns 160 or so degrees in around 12 seconds. We see here that the faster the corner, oftentimes the slower the car is actually turning. How can we make the car naturally tend to turn slower for faster conditions? This can be done by moving weight forward in the car. This slightly reduces front tire efficiency, and also creates a center of gravity position such that the car will rotate more slowly when driven properly.
There are other benefits of having the weight farther forward for faster cornering:
1. Forward weight contributes to stability under deceleration. Provided your brake bias is properly moved forward in proportion to the weight, and the car gets out of shape under braking due to contact (or driver error), it is easier to snap the back end in line behind the front.
2.The farther forward your car's center of gravity is, the easier it is to "gather it back up" if you get the car crossed up in a corner, much the same as under braking. If the weight is near the back and you break loose, that's a lot of weight to get back under control. You can snap if back in shape more quickly with forward weight. Because less time is spent steering right to regain control, this can reduce the likelihood of overcorrection.
3. These higher-speed corners typically require taller gear ratios, and are often accompanied by substantial banking. Both conditions reduce the potential for rear wheelspin under acceleration. Thus, lower rear weight is less likely to create a wheelspin problem.
Now, we've mentioned banking. What does banking demand from your car setup? Banking allows higher cornering speeds on a turn of a given radius. This speed on a banked curve induces tremendous vertical loads on the car's suspension and tires. This vertical loading dictates stiffer springs to keep the car from bottoming out on the track. The compression of the suspension caused by these vertical forces also changes the attitude of the car in the airstream, and this can have a large effect on the car's aerodynamic qualities. This effect has been used to advantage at Daytona and Talladega for some years to get the back of the car to squat down in the banking, reducing drag in the corners. This was accomplished by using very soft rear springs. High-rebound rear shocks also were utilized to slow the uncompressing of the rear suspension, to try to keep as much rear end squat as possible after exiting the corner. This practice is prevented by rules now governing rear spring stiffness and shock construction at these tracks. It is also possible to apply this principle in reverse to get the front of the car down in corners to try to generate downforce at other tracks.
Banking in general, dictates stiffer springs, but not necessarily uniformly increased stiffness all around. Remember, higher corner speed normally implies more forward weight. The heavier front of the car necessitates more stiffening of springs at the front than at the rear. Consider that if you move 100 lb to the front of the car (a big weight change), on a steeply banked track that might increase the total vertical load by nearly 220 lb. Consequently, you may use very nearly the same rear springs at the rear of the car both for California and Atlanta, but your front springs will be approximately twice as stiff at Atlanta.
Orientation of the body for downforce can lead to unique spring selection considerations. Indianapolis and Martinsville are similarly flat tracks. At Indy, the car's downforce itself can drive the nose of the car quite low. At Martinsville, the car does not go fast enough to do this. A car running at Martinsville will thus have its spring selection driven entirely by braking-, cornering-, and acceleration-induced load transfer issues. It is common, however, to see cars at Indy and Martinsville with similar front spring stiffness. But at the rear? At the rear, they're widely different because speed can be gained through aerodynamic effect at Indy that can't be realized at Martinsville.
Now, having sprung the car for maximum aerodynamic effect, where do we go if this improved-aero car doesn't have suitable handling balance? Well, we reach for swaybars. Go to a bigger front bar if we're loose, smaller if we're tight. The rear bar is used infrequently, mostly at road courses. Martinsville, Loudon, and Phoenix are also candidates for use of the rear bar. It has also seen use at Fontana, and recently at Michigan. It is possible to achieve good handling balance at most tracks without a rear bar, so it's not used a lot. But nothing is wrong with trying the rear bar wherever you want: Balance the car without it, hook up the rear bar, and then increase front bar size until you have balance back again. The theoretical benefit of doing this is flatter cornering.
Flat cornering is usually a desirable objective. Since the car rolls to the right in left-hand corners, right side springs typically end up being stiffer than the lefts. Stiff right-side springs keep the right side of the car from rolling over to the ground, softer left side springs let the left side of the car compress toward the pavement in the corners on steeply banked tracks. Vertical forces increase on the right side sharply as banking increases, so the difference between right side spring stiffness and left side spring stiffness is typically greater on steeper banking. On a road course, the car turns both ways, so the two sides of the car will be symmetrically sprung.
You can find many sim racers in the online racing community that can tell you something about lateral load transfer in a corner. I would suggest you also pay close attention to longitudinal (forward or rear) load transfer. Does the car push under braking? Don’t just look at the brake bias, compare your two front springs – the stiffer one will pick up most of the load that transfers forward under braking. Consider as well that the LF tire probably started out as the more heavily loaded of the two as you began braking. Think in the same terms at the rear of the car. Some people like to think in terms of diagonal load transfer, when acceleration and cornering are combined – that weight transfers from RF to LR, LF to RR, and vice versa. You can choose to think of it as a diagonal process if you grasp it better that way, but breaking it down into lateral and longitudinal “chunks” allows you to consider load transfer as two smaller problems rather than one big one.
Having spoken about diagonal load transfer, now is probably a good point to discuss wedge. In a real Winston Cup car, we've got a forward weight bias, front bar with no rear bar, and stiff front springs, with the RF being stiffest of all. It adds up to a heavily loaded right front tire. Wedge, or diagonal percentage, will typically be reduced to 48-50% in response to this. This takes cornering load off the RF tire. It also makes it looser. So if your car is balanced but runs a hot right front tire, taking wedge out will help, but be prepared to do something else to tighten the car back up. Your RF tire is almost always the most heavily loaded tire in a corner, but it's not always the hottest. Because your rear tires accelerate the car and the fronts do not, the work of acceleration can make your RR tire as hot as the RF. If you're driving a loose setup, the RR may get even hotter, especially if wheelspin is prevalent.
At this point, we can move on to talk about tires. I can't generalize much beyond the game manual as far as tire pressures are concerned – Several tires are in use in Winston Cup racing, each with unique characteristics. Follow the manual's recommendations on pressure and reading the tire by the temperatures. Just remember to use higher pressures for qualifying, because with the few laps you run in qualifying, the air in the tires won't heat up enough to properly fill out the tire, if you use normal racing pressures.
Moving on, why does a good-handling car typically require more LF camber than RF camber? The front suspension of a Winston Cup car is an independent suspension of the type called a short-long arm (SLA) design. In an SLA suspension, the camber doesn't change a lot with body roll, but it changes a lot with ride compression; it pulls both tires to more negative camber. Now, when turning left, the LF tire generates more lateral force with positive camber, and the RF generates more lateral force with negative camber. So, when downforce or banking compress the front suspension, the RF tire builds more negative camber and can easily be over-cambered. The LF tire loses positive camber. Both of these situations are unfavorable, so the car is set up with large amounts of LF positive camber, and only modest amounts of negative RF camber. At the rear, camber doesn’t change much under cornering loads, and NASCAR doesn’t allow much, so it’s typically maxed out at the allowed amount.
Going further with geometry, caster is used to tilt the steering axis of the front wheels. Positive caster is when the top of the steering axis is raked toward the rear of the car. Positive caster will de-wedge (take weight off of the RF-LR diagonal) when the car is steered into a left-hand corner. This de-wedging effect helps free up the car in turns. So, it works like a wedge adjustment that’s only there when you steer the car. Caster split occurs when the left and right front wheels are set with different caster angles. Caster split is popularly believed to make the car pull to one side on straight stretches. This is not quite true, but here is what happens: For conventional steering geometry, the forces generated by the tires want to steer the tires, even when running straight. When the car is symmetrically set up, these forces are equal, and they oppose each other. With caster split, the asymmetry in position of the steering axes results in an unequal transmitting of tire forces into the steering linkage, and the front wheels and steering wheel will rotate, unless the driver opposes these imbalanced forces. So caster split does give the driver a noticeable pull in the steering wheel, but as long as the driver resists that force, the car will go straight. (As straight as possible with a Winston Cup car, as tire stagger makes the car want to go left all the time.) Those of you with force feedback wheels should be able to sense this imbalanced effect of caster split.
Toe-out is used to achieve stability on initial corner turn-in. An eighth of an inch of toe-out is common. Having a non-zero toe angle means that the front wheels are not pointed straight ahead when the car is running straight. Consequently, toe (in or out) generates forces in the tires that dissipate some of the car’s forward energy. Thus, at restrictor plate tracks, the toe angles tend to be quite small. Toe settings can also help a real car realize stability in cross-winds, but the explanation is complex and requires more space than I have in this article.
The track bar affects the handling of the car in a number of ways. The position of the track bar affects what is called the rear roll center, which dictates how the transfer of weight from the left side of the car to the ride side during cornering is distributed. This affects your handling balance. Typically, lowering the track bar tightens the car up. Raising it make the car looser. Also, the angle at which the track bar is positioned affects how much the rear of the suspension moves laterally, when the rear suspension compresses. The greater this angle (track bar split, or difference between right and left heights), the more it moves. When the right side is mounted higher than the left, the rear wheels get pushed left during compression. Due to the way the rear suspension is kept in the car, this causes the rear wheels to turn to the right. The reverse will happen if the left side is mounted higher than the right.
I want to touch now on the subject of ride heights. Ride heights, as defined for the NASCAR Winston Cup Car, are the heights of the ends of the frame rails above the ground. Because of the way NASCAR dictates vertical positioning of the body of the car, once a car is built, the ride heights it was built with are essentially fixed. Let me explain. A “standard” setting of ride heights is 5” for the LF frame rail end, 6” for the LR, 6” for the RF, and 7” for the RR. As the builder of your NR2003 car you have the freedom to “construct” the car with frame rail heights that differ from the above. You build the chassis, and your body hanging guys build the body of the car. By NASCAR rules, a defined (by NASCAR) point on the roof of the car must be 51” above ground. NASCAR also defines two “quarter panel heights” that must be met. These points are essentially where the rear spoiler crosses over the deck lid (trunk) seams. The left point must be 35” above ground, the right point must be 36” above ground. There’s not a lot of leeway given in these measurements; they therefore fix the height and orientation of your car body. When you adjust the ride heights of your NR2003 car, essentially you are “rebuilding” the car to have a different ground clearance, but your body height remains fixed – you are moving points on the frame of the car. Such rebuilds are rarely done to a real car; however, teams do have a variety of ride heights built into the different cars in their stable.
Raising the ride heights allows you greater freedom in spring selection on tracks with substantial banking. Because the frame rails that you raise contain the tungsten ballast blocks that bring the car up to minimum weight, raising the ride heights does raise the as-built center of gravity of your car. So, you want the frame rails raised no higher than is necessary to prevent “bottoming out” of your car’s frame on the pavement. You will want the freedom you have in NR2003 to easily experiment with different ride heights as you race and test at the various tracks.
Finally, shocks. Shocks apply force to the suspension only while the suspension is moving on the car. Compression adds vertical load to a tire while it is being pushed up in the car. Rebound takes vertical load from a tire as it is descending out of the car. Both body motion and banking changes cause wheel position changes to occur. Is your car tight only as it heaves up on the banking, or as you start to turn the wheel and the body begins to roll? A shock change may be your fix. Realize, however, that in corner entry, it is possible at any one time, to have:
Right shocks compressing, left rebounding,
Front shocks compressing, rear rebounding,
RF compressing, others rebounding, or
All shocks compressing.
And as always, expect opposites to be possible on corner exit. Bumps in corners may create combinations in additions to those listed above.
I’ve given you a few principles here, but not a lot of answers, it’s more satisfying for you to find the answers you need on your own. As you drive the car and try to improve it, think about what the car is doing at the points on the track that concern you. Is the car pushing? Then one of your front tires is either overworked or underutilized (Or is it?). How do you relieve it, or optimize its performance? Is this occurring on corner entry, mid-corner, or exit? If you exhaust the possibilities at the front, is something at the rear being too effective in keeping the car from turning? Is it occurring when the car is pitching, rolling, or being heaved or released vertically by the banking? The wheels respond to the track first, shortly afterward, the body responds to what the wheels have done. What then is the wheel motion that is going on at the point of your problem? Is your problem occurring while the wheels are moving, does it continue or go away as the car settles into a corner? Consider your front-rear dynamics and your vertical dynamics, as well as the lateral dynamics of a cornering situation.
The game manual recommends you change one variable at a time. Until you learn the dynamics of your car well, this is a useful practice; it teaches you what various changes do. As you gain familiarity with the behavior of your car, you will be able to understand and manage it as a system, realizing that the necessary solution to a given handling problem produces another effect, and you’ll know beforehand what additional change or changes are needed to address that as well. Keep your cool and think through your decisions, and you’ll be able to manage a mad thrash like you’re in the bigs. Good racing and good luck.
The Jasper Setups
In NASCAR Racing 2003 Season, you’ll find a “Jasper” setup for each track. These setups come largely from the last couple of years of our race shop. They are representative of current setup thinking in Winston Cup racing. I’ve modified them somewhat so that I’m not ‘selling the farm” on our best Ideas. I’ve also tested each of them for drivability in your game. I do not consider them “optimum”setups for the game; they’re simply representative of what a real team might plausibly run.