Budget Parts Decisions - Material Selection For The Weekend Racer

We have options in the selection of the materials we use to construct our racecars. Within reason, we can use almost any materials. The only restriction may be our budgets and the rules that govern the construction of the cars.

The rule makers have made many of the selections easier by legislating away the options of using expensive or inappropriate construction materials. But racers being racers, many of us may want to play with some specific materials to gain an advantage, real or perceived. That is, after all, what being a racer is all about: Looking for the advantage over the competition, either by out-driving the guy next to us or by building a better car.

The majority of the cars raced on Saturday nights are made from various grades of steel, aluminum, various other metals, and some plastics. We still have options that allow the racer to try improvements. Available materials range from very exotic and very expensive materials that, truth be known, are not options for the Saturday night racer, including entry-level Bomber Stocks to full-out Dirt Late Models. That's true due to cost, application and the infrastructure to support those materials.

Carbon-carbon as brake material is a good example. It's a high performance friction material that is very light, has high heat capability, is incredibly expensive, and requires a high infrastructure to support. It's simply not a good fit for the Saturday night racer. The cost of a single disc would probably support a Saturday night racer for the majority of the season yet offer a negligible performance advantage.

Among Saturday night racers, you will find very few parts with beryllium copper alloys. Although these materials are incredibly light and have some very high heat capabilities, they have no place on the cars we race. If we were to spend several thousand dollars on beryllium or carbon-carbon we may have saved some weight, but as the majority of the cars have to add weight to make the legal minimum, we really have not gained much. We could claim some performance gains due to lower weight of the brakes and the lower rotating weights, but as we accelerate from the 40 to 80 mph range at our local 31/48-mile dirt oval, the value of this type of part is negligible.

It is easier to list the materials that we will probably not find at the local short track on the nights that the Street Stocks, Modifieds, and Super Late Models will be racing. You will not find an abundance of carbon-fiber parts with the exception of some high-end helmets and HANS devices. Magnesium, titanium, carbon-carbon and beryllium components will be as rare as low-cost sticky tires that last all season.

The Saturday night racer needs to concentrate on materials that are available at a moment's notice at the local metal or plastic dealers. In fact, there are many different racing parts vendors who stock the most commonly used materials that the local racer will need. It is possible that the local parts vendor has what you need in stock. These are products that have very common automotive and consumer uses so that racers do not have to order materials with long lead times or have to pay special freight charges to get what we need.

The materials we need to concern ourselves with are steel in its various forms, including sheets and tubes, in both round and square. Also included is aluminum, mostly in sheet form and possibly some of the smaller tubes that may be used for tie rods in lighter-duty applications and possibly for some carburetor linkages. Add to the list plastic sheets that can be used for various body panels, and within the plastic family, add products like Lexan(r) that can be used for windows and windscreens.

If we look into the driver's compartment in the average Street Stocker we will find that the majority of the interior is but a shell of the car it started out as. You will likely find that only the firewall and the barest minimum of brackets and supporting structures are left to hold a very basic dashboard and instrument panel.

If we look at an IMCA-type Modified, we will see a good bit of sheet metal used to form the driver's compartment and the body. The driver's compartment is usually a mixture of steel sheets and aluminum. Some sanctioning bodies require the outer portion of the driver's compartment rollcage to be covered with steel plates welded to the 'cage to add even more strength to the driver's side. This is a good idea even if the sanctioning bodies do not require the additional steel. The added protection for the driver is worth the effort.

These materials are readily available to racers through most metal dealers, and some salvage yards sell new metal products as well as surplus metal. If you want to save money, you may be able to use surplus metals that many scrap and salvage yards sell. I have been able to locate very specific aluminum sheets in alloys that were clearly identified on what looked to be new sheets. These may have some surface imperfections, such as scratches and dents that may make the material look less than perfect, but for my particular application, they worked just fine.

Exercise care, however, as many alloys of aluminum can't be welded and will not lend themselves to uses in fabricated structures that require welding. If you are purchasing metals from a scrap yard or a recycling center, make sure you know what you are getting. Ask questions and make your material requests very specific. Know the sizes of the material you need. If you need a section of 1.5-inch diameter 1010 steel DOM tubing with a wall thickness of 0.090, then that is what you should be requesting.

When you are building a component you need to ask questions that will help determine the material you should be using. Here are some examples:

* Will the part be seeing high heat? (I'm referring to exhaust gas temperatures.)
* Will the part require a high level of strength?
* Does the weight of the part matter?
* Will I be replacing this part on a frequent basis?
* Is the material weldable?
* Is the material legal in the series I will be racing in?