Racing transmissions are pushed to the limits of their largely OEM-based designs by engines that are four to 10 times stronger than their original engineers had intended. Over the last four decades, we've increased the strength and durability of all the driveline components, however, as it is often said: "anything can happen in racing."
The unexpected release of so much energy transmitted through the driveline cannot be understated. The result of a malfunction can, in some scenarios, explode the drums or flexplates of a racing car into dangerous shrapnel (see above).
Therefore, the sanctioning bodies rely on the SFI foundation to provide safety guidelines to protect both the racers and the spectators.
Just above, you can see the successful results of our Powerglide transmission housing after a drum and flexplate test explosion. A modified high gear drum and flexplate were spun at more than 10,000 RPM until they separated.
The bellhousing and case both remained intact. Shields and blankets also provide similar protection. BTE strongly recommends using some sort of SFI approved safety system in any racing driveline.