Maximum rated horsepower allowed in factory stock cars

[Coleydog]

Interesting how the SFI got those numbers? Did they take a 3000, 3600 and a 4000 lb car, wreck them, then see how they faired? I know there's math involved, but in my opinion, way to many variables unless there's one cage fits all. If pushing the limit of 1-5/8" cm, go to 2", more than doubles the strength. There are ways around this dilemma, look at NASCAR. Over 4000lbs and those cars hit a few walls time to time. Amazing when you're been at the top for a long time, after awhile questions don't get asked.
Like I said, my opinion, Mike

[SSDiv6]

Originally Posted by Coleydog

Interesting how the SFI got those numbers? Did they take a 3000, 3600 and a 4000 lb car, wreck them, then see how they faired? I know there's math involved, but in my opinion, way to many variables unless there's one cage fits all. If pushing the limit of 1-5/8" cm, go to 2", more than doubles the strength. There are ways around this dilemma, look at NASCAR. Over 4000lbs and those cars hit a few walls time to time. Amazing when you're been at the top for a long time, after awhile questions don't get asked.
Like I said, my opinion, Mike

SFI uses actual crash data and analysis to come up with the specification. In addition, many of the top chassis builders are also consulted.
It is not an arbitrary number.

[trode424]

I know this is a old thread, but has anyone got any clarification on this? Thanks, Todd

[SSDiv6]

Originally Posted by trode424

I know this is a old thread, but has anyone got any clarification on this? Thanks, Todd

Nothing has changed.
This is the only SFI Guidance applicable to drag racing stock body cars:

SFI Spec 25.5D - Full Bodied Car Stock or Modified/OEM Floor Pan and Firewall with OEM Frame or Uni-Body Construction
– 7.50 to 8.49 Seconds; 3,600 lbs. Maximum
Effective Date: May 5, 2018

SFI Spec 25.6 - Full Bodied Car Stock / Truck or Modified/OEM Floor Pan and Firewall with OEM Frame or Uni-Body Construction
– 7.99 to 8.49 Seconds; 5,000 lbs. Maximum
Effective Date: August 26, 2016

[trode424]

Originally Posted by SSDiv6

Nothing has changed.
This is the only SFI Guidance applicable to drag racing stock body cars:

SFI Spec 25.5D - Full Bodied Car Stock or Modified/OEM Floor Pan and Firewall with OEM Frame or Uni-Body Construction
– 7.50 to 8.49 Seconds; 3,600 lbs. Maximum
Effective Date: May 5, 2018

SFI Spec 25.6 - Full Bodied Car Stock / Truck or Modified/OEM Floor Pan and Firewall with OEM Frame or Uni-Body Construction
– 7.99 to 8.49 Seconds; 5,000 lbs. Maximum
Effective Date: August 26, 2016

Does 3600 include driver? Ive seen plenty of 2018 and up copo's and cobra jets running FS/AA .