SFI flexplate mandatory in all v8s Jan 2024

[Billy Nees]

Originally Posted by Chevy55

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.

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?

[Charlie Yannetti]

Originally Posted by Billy Nees

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

This could be the question of the day.. especially that I hear more and more people saying that the tracks that they race at, don't require this, or don't require that..

[Mark Yacavone]

Originally Posted by Billy Nees

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?

Seems to me they rush out these new rules to head off a lawsuit,rather than thinking them through first.
Then again, maybe there's no one out there that CAN think them through first

[SSDiv6]

Originally Posted by Larry Hill

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.

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 two-steps.

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

[joe huestis]

Originally Posted by Mark Yacavone

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

or to a 267 chevy U/SA ?

[Paul Precht]

A Mopar flex plate barely extends a 1/2" beyond the bolt circle of the converter, if it explodes it's because the converter exploded otherwise not really possible.

[dragracerray]

Originally Posted by SSDiv6

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

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

[SSDiv6]

Originally Posted by dragracerray

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

Corrected...meant two-steps, not rev-limiter.

[Chevy55]

Originally Posted by Billy Nees

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?

Billy maybe they're afraid of scaring away kids with newer high powered street cars that come to run bracket.

[Mark Yacavone]

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?