SFI flexplate mandatory in all v8s Jan 2024

Did anyone actually investigate the car that sent the shrapnel into Hildago’s car? Was it a stock flexplate? When is the last time an automatic flexplate has come apart at a race and come out of a car? I’ve seen a trans or 2 explode and send parts out.

For years (before I was born) a steel SFI flywheel has been required for any manual trans combo regardless of manufacturer or performance level.
Now after this they want to employ the rule for automatic cars. The rpm and hp range of these engine have advanced quite a bit in the last 40 years. Probably exceeding the limits of stock parts at this point. There is always exceptions to the rules for combos. If you have to rebalance an SFI flexplate for an external balance I’m sure it can be done legally. Probably splitting hairs at this point with that argument, but that is what we do here.

[Regan Wilson]

Originally Posted by Todd Hoven

Did anyone actually investigate the car that sent the shrapnel into Hildago’s car? Was it a stock flexplate? When is the last time an automatic flexplate has come apart at a race and come out of a car? I’ve seen a trans or 2 explode and send parts out.

For years (before I was born) a steel SFI flywheel has been required for any manual trans combo regardless of manufacturer or performance level.
Now after this they want to employ the rule for automatic cars. The rpm and hp range of these engine have advanced quite a bit in the last 40 years. Probably exceeding the limits of stock parts at this point. There is always exceptions to the rules for combos. If you have to rebalance an SFI flexplate for an external balance I’m sure it can be done legally. Probably splitting hairs at this point with that argument, but that is what we do here.

The Flexplate was inspected and deemed a parts failure by NHRA. No fault by the racer it belonged to as it was within the given rules.

[mike britt]

In this case the flexplate did not break or come out. It was still bolted to the crankshaft. What happened was the ring gear welds came loose and the ring gear started coming apart in pieces. I found one piece about 2 inches long by the accelerator pedal in bills car. It looked like a stock flexplate to me, but the rules did not require the car to have an SFI flexplate.