SFI flexplate mandatory in all v8s Jan 2024

[Dave Noll]

...

[Duane Eiskant II]

Just internally balance the rotating assembly then no need to modify the SFI flexplate. Hopefully everyone sees me being a smart *** about this.

[Mark Yacavone]

Originally Posted by Duane Eiskant II

Just internally balance the rotating assembly then no need to modify the SFI flexplate. Hopefully everyone sees me being a smart *** about this.

Duane, NOT being a smart*** about this but did you ever see a 301 Pontiac crankshaft?

[Duane Eiskant II]

Mark, Nope haven't seen a 301 crank. Just adding thoughts to NHRA's thinking. Since this is opening a rabbit hole no body wants to go down

[Mark Yacavone]

Originally Posted by Duane Eiskant II

Mark, Nope haven't seen a 301 crank. Just adding thoughts to NHRA's thinking. Since this is opening a rabbit hole no body wants to go down

Okay, neither have a lot of guys here, I suspect.
It only has two opposing counterweights, front and rear.
The flex has a big balance weight on it. I wouldn't want to fool around with that bit of Pontiac engineering ;-)
TCI makes an SFI for the 400, which is the same except they are internally balanced.
This brings us to modifying an approved part. I see that this would have to be re-done every three years too. It's not gonna pass re-cert.

I seem to remember hearing that the perp in the Texas was invited to the barn for a look see. Now supposing one comes apart next year, you can bet it's coming apart too.
If they happen to find a modified SFI unit that failed, who do you suppose is going to have to pay that fine?
There are at least three of those 301 cars out there. These are 6 grand in the lights, max combos. What are they supposed to do ?

As my lawyer would say "arbitrary and capricious"

Originally Posted by Jim Bailey

Never had any problems with any SFI certified Mopar Flex Plates "UNTIL" I started to two step. We're our own worst enemy. If you two step, the flex plate must become a part of your service routine. Just saying .........

How long ago was that? 90’s ?

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.

[Duane Eiskant II]

Originally Posted by Mark Yacavone

Okay, neither have a lot of guys here, I suspect.
It only has two opposing counterweights, front and rear.
The flex has a big balance weight on it. I wouldn't want to fool around with that bit of Pontiac engineering ;-)
TCI makes an SFI for the 400, which is the same except they are internally balanced.
This brings us to modifying an approved part. I see that this would have to be re-done every three years too. It's not gonna pass re-cert.

I seem to remember hearing that the perp in the Texas was invited to the barn for a look see. Now supposing one comes apart next year, you can bet it's coming apart too.
If they happen to find a modified SFI unit that failed, who do you suppose is going to have to pay that fine?
There are at least three of those 301 cars out there. These are 6 grand in the lights, max combos. What are they supposed to do ?

As my lawyer would say "arbitrary and capricious"

I agree Mark. Both of my convertors when ordered from ATI were done with the 3/8 bolt size just to avoid this.

[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.