Originally Posted by Chevy55 (Post 681789)

2023 NHRA RULE AMENDMENTS

Beginning January 1, 2024, SFI 29.1 flexplate mandatory on all V-8 vehicles. Any car running quicker than 9.99, SFI 29.1 automatic transmission flexplate and SFI 30.1 flexplate shield mandatory. See General Regulations 2:12, 2:14.

Originally Posted by Billy Nees (Post 681782)

Now just to be "fair", this ruling is going to apply to all V8 bracket cars also right?

Originally Posted by Billy Nees (Post 681795)

why should it apply to a "U/SA 273 Mopar" or a P/SA 301 Pontiac that rarely if ever sees over 6 grand?
And where am I supposed to find this 301 Pontiac SFI approved flex plate?

Originally Posted by Larry Hill (Post 681747)

I don’t think the ring gear knows any difference if it’s being spun to 7000rpm by a BBC, SB2, SBC, V6, or a 151.

Originally Posted by Mark Yacavone (Post 681793)

Yes..Okay.
So how does that apply to U/SA 273 Mopars?

Originally Posted by SSDiv6 (Post 681802)

There are many variables applicable to flexplates.

Lots of considerations such as horsepower, RPM range, size/diameter, one-piece or two-piece design must be considered.

The SFI 29.1/29.2 test entails the flexplate turning 12000 RPM's for one hour. However, the test equipment does not simulate the effects of heat, engine load, flex, having a torque converter attached to it and transmitting the horsepower and torque to the drive line. When applicable, add a car with a transbrake and/or rev limiter.

I consider both the SFI harmonic balancer, flexplate or flywheel/cluth a safety item. In the early days of Modified Eliminator, with heavy flywheels and OEM flexplate, saw them come through the floor, cut fuel and brake lines many times causing injury and damage.

Although high in cost, my preference are the Reactor Products (without the inertia ring) and Meziere flexplates. They have a great selection of configurations and weight for different end applications.

Other great options are the ATI, TCI billet line and ATF

Originally Posted by dragracerray (Post 681808)

SS,
Two Steps cannot be good for a flexplate either. Ray

Originally Posted by Billy Nees (Post 681795)

This ruling only applies to S/SS cars and I'm not saying that in most cases it isn't a good idea BUT it doesn't apply to a low 10 second bracket car so why should it apply to a "U/SA 273 Mopar" or a P/SA 301 Pontiac that rarely if ever sees over 6 grand?
And where am I supposed to find this 301 Pontiac SFI approved flex plate?
Maybe a re-think and a change to 11.99 or quicker might be prudent?

Originally Posted by Billy Nees (Post 681795)

This ruling only applies to S/SS cars and I'm not saying that in most cases it isn't a good idea BUT it doesn't apply to a low 10 second bracket car so why should it apply to a "U/SA 273 Mopar" or a P/SA 301 Pontiac that rarely if ever sees over 6 grand?
And where am I supposed to find this 301 Pontiac SFI approved flex plate?
Maybe a re-think and a change to 11.99 or quicker might be prudent?

Originally Posted by Mark Yacavone (Post 681812)

Billy , Just mark your tech card with the ATI 400 Pontiac model.
If anyone asks , I'll say I saw you put it in .
I'm sure you will anyway..it's only a deuce , plus re-balancing
Still not sure if you can add or take away weight on an SFI approved flex.
Anybody?

Originally Posted by L.Fite (Post 681818)

You CAN...
I have in the past... (removed weight for balance)
Honestly never gave it a thought, just part of building a motor...
Will it recertify?
Don't know...
THAT is the true question...
Hmm...

Originally Posted by Billy Nees (Post 681822)

Soooooooooooooo, "You CAN..." but can you LEGALLY?

Originally Posted by 1347 (Post 681816)

Maybe a call to our division tech rep, whoever that is right now, or somewhere higher up the ladder will get an answer. i can't really believe if they don't make one, that the answer will be that you need to park the car.

Originally Posted by e vassar (Post 681830)

So..is there an expiration date?
I have an SFI flexplate on my car now that I will examine for any cracks etc..but does it make sense to take one off that has never broke,and replace with one that might?

Originally Posted by Duane Eiskant II (Post 681855)

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

Originally Posted by Duane Eiskant II (Post 681860)

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

Originally Posted by Jim Bailey (Post 681764)

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 .........

Originally Posted by Mark Yacavone (Post 681862)

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 Todd Hoven (Post 681881)

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.

Originally Posted by mike britt (Post 681906)

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.

Originally Posted by mike britt (Post 681906)

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.

Originally Posted by Mark Yacavone (Post 681857)

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

Originally Posted by mike britt (Post 681906)

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.

Originally Posted by Paul Precht (Post 681907)

The ring gear is the issue for sure and yet Mopars that don't have a ring gear or an explosion possibility are forced to be a part of the new rule.

Originally Posted by Mark Yacavone (Post 681812)

Still not sure if you can add or take away weight on an SFI approved flex.
Anybody?

Originally Posted by Billy Nees (Post 682688)

I had a (somewhat) cordial discussion with my DTD at Numidia this weekend and would like to think that I made some inroads into this "all V8s" need an SFI flexplate thing.
I would like to think that this ruling will be aligned with the need for trans and flexplate shields based on E.T.s and not just an arbitrary ruling based off of a "million-to-one" incident.
And I've got a "Billy question" here, since this "issue" involved the starter ring gear and not the actual flexplate itself, are Mopars going to have to have SFI approved torque converters?

Originally Posted by Billy Nees (Post 682688)

I had a (somewhat) cordial discussion with my DTD at Numidia this weekend and would like to think that I made some inroads into this "all V8s" need an SFI flexplate thing.
I would like to think that this ruling will be aligned with the need for trans and flexplate shields based on E.T.s and not just an arbitrary ruling based off of a "million-to-one" incident.
And I've got a "Billy question" here, since this "issue" involved the starter ring gear and not the actual flexplate itself, are Mopars going to have to have SFI approved torque converters?