A big part of maximizing your safety has to do with proper component installation. Since we've been talking about belts we'll stick with that subject. Safety belts must pull from a straight angle in the event of an accident. When that happens, the mounting hardware minimizes the bending stress in that fitting and the whole system works properly. One of the easiest ways to ensure that happens is to make sure that when your belts are installed that no part of the straps are rubbing against any surface that can cause that webbing to fray. Remember to also periodically check the anchoring mechanisms to make sure they haven't loosened over time.
While securely-mounted belts are important you also have to remember that belts need to be as short as possible to reduce stretching for better control of driver movement in the event of an accident.
Chart C (previous page) shows some key angles that should be followed when designing the optimum fitment geometry to minimize movement of the belts. Lap belts perform best when mounted at an angle between 45 and 55 degrees relative to the longitudinal axis of the vehicle (Part A in Chart C). This angle allows the lap belt to properly restrain the pelvis in the event of an upward pull of the shoulder harness.
Part B of Chart C shows what happens with a system that has the wrong belt angle. The shoulder harness pulls the lap belt up off the pelvic area and into the abdominal region. A hard enough hit with this configuration and you are likely to hurt some internal organs.
Pop Rivets have a place, and it's not on your window net. Do it correctly and weld in bott
Finally, do not forget that the ideal position of the shoulder harness is anywhere between 5 degrees below and 30 degrees above the driver's shoulder, as seen in Part C of Chart C. An attachment point significantly below the driver's shoulder will result in a spinal compression injury, while one too far above the shoulder (greater than 30 degrees), will provide little resistance to forward motion of the driver's upper torso. In addition to overly stressing the mounting points, you run the high risk of hitting the steering wheel with your face or chest which could in turn cause a neck injury. The shoulder straps should also be 3-6 inches apart behind the driver's neck to prevent slippage off the shoulders.
Keep in mind that these installation tips are just suggestions based on SFI recommendations and our own personal experiences here at Circle Track. When preparing to mount your belts, you should always follow the installation instructions provided by the seat belt manufacturer and contact them directly should you have any questions.
Window nets are designed with two functions in mind. Number one, they keep your arms, head, etc., inside the car in the event of a hard crash or roll over. More importantly, and to some extent less thought of is Number two, the window net keeps foreign objects such as other car parts, debris, and more out of the driver's compartment. SFI rated window nets can sustain a lot of impact, but only if they are mounted properly. Proper mounting means having two top and two bottom brackets welded to the rollcage.
Frankly, it surprised us when we found out that many racers will use pop rivets to attach the bottom bar to their car's door panel. This may be cheaper and easier to do than welding the proper bracket in place, however it is far more dangerous. The pop rivet and sheet metal is nowhere near as strong as a good solid weld. Rivets cannot withstand the g-forces associated with even a medium hit and will just rip out of the panel like it was paper. So if you are one of those racers taking this short cut, rethink the purpose of that net and weld some good brackets in all four corners. It could just save your life.
Racing is an inherently dangerous sport and, while the tracks and sanctions have rules that promote safety, the final choice of what to wear and how to build your car is yours and yours alone. Safety starts with you, the driver, and just because your track says you need a minimum of a SFI 3.2A/1 suit doesn't mean you shouldn't upgrade to a SFI 3.2A/5. There are plenty of high-quality safety products on the market for a reasonable price. After all, it's pretty hard to race from a hospital bed or worse from six feet under.