Exactly how are those Winston Cup cars built?

By Eddie Dickerson, Circle Track Magazine
August 16, 2001
2:23 PM EDT (1823 GMT)

The March 2001 issue of Circle Track featured an article on how to use a chassis jig ("Jigging It"). I want to take that a little further by giving readers a look at how a high-end Stock Car racing team, such as Hendrick Motorsports, puts together the cars you see in the NASCAR Winston Cup Series each week.

Granted, most of you do not have the facilities or budgets to build cars as we do at Hendrick Motorsports; however, auto racing goes by the "trickle-down effect." It has to start somewhere. And you never know -- there might be a trick to how we put our cars together that you can use in your own shop.

There are certain aspects to building a car that need to be pre-determined before you put that first piece of metal on the jig. Most of these aspects, such as length, width, and type of materials to be used in building the car, will be set by your sanctioning body.

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For example, NASCAR requires Winston Cup teams to use 2x3-inch, 83-wall mild steel tubing in the front clip. Other predetermined values to be considered are framerail height, tread width, and the type of car-short track, inter-mediate track, or superspeedway. I suggest you study your sanctioning body's rule book.

To make it through tech, you obviously want to build a car that is within the rules, but you should also build the car to your advantage. Use your rule book to get the car as close to running at your advantage while staying within the rules.

After you have reviewed the rule book and your list of predetermined values, it is time to make a blueprint of the car. The blueprint, or plan, that you come up with for building a car is no different than one for building a house. You have your set values and materials, and you go from there.

Many people ask how we came up with the first blueprint for our cars. Basically, we started years ago building a car that was within the rules of the series in which we were running. From there, with the help of testing and technology, the car evolved day by day, month by month, year by year to what we have now. But you can always start from scratch. You need to know that the framerails have to be a certain width apart from each other off of the centerline. Often, this will be determined by the type of car you are building. Will it be a short-track car for Martinsville or a superspeedway car for Daytona and Talladega?

One thing to keep in mind is that you never want the race car to bottom out. When this happens, your chassis hits the pavement, unloads the suspension, and causes the car to slide up the track. Different cars at different tracks will pull more or less g's.

Hendrick Motorsports is able to crank out about one car a week.

On a flat track, such as Loudon, the car will go down in the corner and want to roll over on the right side. At a superspeedway, you get more even spring travel because you run against the banking. Basically, you always need to consider the types of tracks you will run on when building your race car. Every track is a different animal.

Once you draw up your blueprint, you need to set up your jig tables. Each jig will have fixtures on it, which are the pieces of the table that are permanent. The fixtures can be thought of as something you can grow to, or build up to.

For example, when building the front clip, there are dummy framerail fixtures that just sit there until NASCAR tells us to change them. Before getting more into the jig table, it's important to tell you the four major components of the car that we build with a jig: front clip, rear clip, centersection, and rollcage. Once you have completed each piece, they come off their respective surface plates and fit together like pieces of a puzzle.

The surface plate is a good, flat surface to start with. Scribe a centerline in the plate. When you assemble the front snout, use the centerline to refer in your mind the left hand and the right hand of the snout.

A worker is fabricating a lower control arm.

Once we have our centerline, we can think back to what we are doing to the left and right halves of the car. For Winston Cup racing, NASCAR says we can have 1/2 inch of offset, so we obviously take advantage of that. This works well for most of the tracks we race on since we are always turning left. If we are running a road race we will even it up, or if the road course has more right-hand turns than left, we will go more the other way to our advantage.

The major reason that we use the jig table is for repeatability. We want to be able to build a great car in the beginning and then keep building that same great car over and over again if anything happens to the original. You always want to make sure your jig fixtures are accurate. You want to make sure all your measurements are accurate and precise so you don't pass a characteristic of a bad jig table through the part you are building.

When building a new car, we start with 25-foot lengths of mild steel tubing. We have to make sure it is within NASCAR tolerance. As I said earlier, our front snout has to be made of 2x3-inch tubing with .083-inch thickness. The rollcage is made from 13/4-inch, 90-wall seamless tubing. The rollcage fixture is the only one in the shop that does not have a surface plate. We just build the cage up and around the fixture.

The framerails on the centersection have to be made out of 3x4 tubing and be .120 inch thick. The whole car is made from mild steel; NASCAR frowns on using aluminum. If a car backs into a wall, we want to see the rear clip crush. The driver will get out of the car and throw his helmet, but he is at least getting out of the car.

A frame section nears completion on the jig.

From there, we build our four major pieces-the front clip, rear clip, centersection, and rollcage-on the jigs. With our predetermined frame heights we then have to determine whether we want the car to run split exhaust pipes, just rights or lefts.

There is always a little racer in you that is trying to engineer some-thing new and says, "let's just try running the pipes out the right side and get that left framerail down as low as we can," because we think that with the weight down low, it will override what is going on with the aero.

There is quite a bit of guessing going on in the business, more than you would really like. When you get all of your stuff rocking and rolling, do your homework, and build a good, smart car, the difference is going to the track and leading, or going to the track, just putting your arm up in the window all day, and running 20th.

Once you put your major pieces together like a puzzle, you have to think about issues such as weight. Generally, you want the car as low as you can get it without dragging, because center of gravity is everything on these cars. Remember to build your suspension pieces as light as your sanctioning body will allow. Suspension components make up the unsprung weight of the car-rearend housing, spindles, and upper and lower A-frames.

A framerail is connected to fixtures on the jig surface plate.

When the chassis goes up and down on the racetrack, it is easy to think of this as the wheels going up and down, but all four wheel patches should be on the race-track. Lighter suspension components make it easier to control the ride of the car and dampen the bounce with the shock absorbers. The heavier your suspension, the more intense the frequency of the bounce.

From the chassis side of the shop, we take the cars to the sheetmetal side. In the chassis shop, we have 43 men working all together. We have about 12 men on the chassis side-some build the parts-and then we have assembly guys or plate men who put the chassis pieces on the surface plates. It takes a week to build a chassis and another week to put on the body.

On the body side of the shop, we have 10 to 12 guys who hang sheetmetal. Once the car gets there, we take out our wind-tunnel notes and hang the body. We tend to move the speedway car bodies forward. The tread width will still be the same, but we make the car skinny and thin for Daytona and Talladega because of the banking. The banking is more forgiving on the car than a short track would be.

A rollcage.

When you have a car running on a restricted engine that has its tongue hanging out; you do anything you can to make the body sleek. You want it like a bullet running down the backstretch.

It all comes down to keeping your car balanced with all four tire patches on the racetrack. No matter what we build, we only have so many inches on the track covered with the tires. With the use of the tunnel, we can determine whether the body needs to be moved for-ward or backward to balance out all of the downforce that is being generated on the chassis.

I like to think of hanging the body like you do on a slot car. You just set it down and move it back and forth according to the kind of track you run on.

Even if you don't have the capacity to build cars as we do at Hendrick Motorsports, there are a few important things to be aware of. First, select good, quality tubing for the construction of the car. Next, make sure you are always conscious of weight. If you need to add a bracket, don't by any means cut back on safety, but ask yourself if you really need the bracket. If you do, make it as light and smart as possible. If you just grab the first bracket you see out of the junk pile, it may very well be OK to use, but remember that it takes thousands of pieces like brackets to put the car together, and the weight adds up.

Just be smart, observant, and always be on your toes-at the track and the shop.

NOTE: All photo credits belong to Meghan Frazier.