Since most new racers come from the street car scene, engine modifications are usually the first area of interest in a race car. New racers want to spend all their time and money getting the most horsepower out of their engine. This is a natural desire, put its quite misguided. Max power output of your race car engine is only going to make a difference once you have made your way to the front of the pack, and as you’ll learn in your first season, the guys up front could beat you with half the horsepower! Your engine is only producing maximum power for a small part of a lap around the track, but you need maximum performance from your chassis for 100% of the time going around the track. I have now told you this, your instructor will tell you this, the veterans in the pits will tell you this, but you will still go out and spend more money on your first race car’s engine than it’s chassis. It’s OK, we’ve all made the same mistake, and it’s practically unavoidable, so go ahead and go get it out of the way…
A race car chassis has many components: the car body, the frame or subframe, the rollcage, suspension, steering, and brakes. It is quite a daunting (and expensive) task to upgrade all these components from street car trim to race car level performance. Again, another good reason to buy a good, used first race car instead of building it yourself. Since most racing is done in production based cars, we’ll keep our discussion there. The body and frame initially starts out pretty much as it did leaving the assembly line, as is required by most race sanctioning bodies. What really transforms a street car into a race car is a roll cage. Roll cages serve two purposes: providing safety to the driver in case of a collision or rollover, and stiffing the frame of the car to provide better handling characteristics. Roll cages are made out of hoops of tube steel welded together in a framework and attached to the car’s frame rails and body at several points (four, six, and eight points are common). Tube size is measured in Outer Diameter (OD), commonly 1.5″, and wall thickness, commonly .095″. Most clubs require larger tubes for heavier cars, and smaller tubes for lighter cars. Rollcages typically weigh several hundred pounds, so there is a large trade-off in performance with a big cage, ie a heavier car needs more horsepower to push it around. There are three ways to get a roll cage into your race car: custom assemble one yourself, purchase a pre-built one and weld it into your car, or pay a fabricator to do it for you. Option one requires a lot of skill, tools, and patience. This is a task I have yet to take on, but it ranks high on the list of skills I want to gain. After racing several cars, I have seen the difference a good cage can make in safety, handling, and ergonomics, and have truly learned to appreciate a quality cage. Option three takes a big checkbook, with option two somewhere between the two. Check out these two sites buidling a cage prefabricated cages
Hmmm, possible overkill on the downtubes?
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