Is this done to eliminate rattles/etc?

I was thinking why not lay thin belting between the SFC and not worry about pulling the carpet up...unless the structural welds are in an area the carpet has to be pulled.

Have just been curious about this for a long time.

Thanks.

 

It adds a huge amount of strength. My Spohn's were stitched to the rocker and floor at various points.

 

Don't quote me on this and I'm open for opinions but I believe they should actually pretrude through the floor for them to serve full purpose. Mounting them next to the stock rails will help stiffen the vehicle, but thinking more about it they are actually doing the exact thing they are ment to correct.I myself have weld on SFC from umi, have not installed them yet due to this problem. Again I'm open for opinions on this matter.

 

Absolutely. When we build our own SFCs for various cars ( early Camaros and Novas, 3rd gens, etc) we typically slice the floor from front sub-frame to rear-frame, weld the square tubing front and back and then completely weld the floor pan to the SFC. Very strong results.

 

@8Mike9 - reducing rattles is an extra benefit. Tieing the SFCs to the body metal makes it all one larger structure instead of two smaller structures. As two separate structures (SFCs not welded to floor/rocker), these are less supported, allowing more flex, and if/when they move separately can lead to rattles.

@skinny z - For the 1st and 2nd gen Camaros, that have large, heavy, actual sub-frames, cutting the floor to weld additional square tubing directly from the front subframe to rear frame rails is best. It is most direct, further ties the body structure to the SFCs, and only gives up some rear passenger foot space. There isn't a direct equivalent in a 3rd gen...

No secret here: 3rd/4th gens don't have separate square tubing subframes. Instead a fully unitized collection of sheet metal panels. The SFC attachment points are at the firewall (vs under the front seats) and back to the same rear suspension connection.

more @ Skinny Z - re-reading your comment sounds like you do cut into 3rd gen floors, and weld in square tube. I assume the extra metal runs along the rocker just like "outer" SFCs. That is definitely going the extra mile and produces the most benefit.
For typical "outer" SFCs, stitch welding to the rockers gives you 90% of the benefit with 10% of the fabrication.

 

I just finished the suspension and chassis for a buddy of mine on his 67 Nova. I built them from scratch for a pro touring/ roadrace style build.

 

I stitched welded, then squeezed seam sealer in just to prevent pockets for rust to form.

 

Thanks for all the info.


I apologize for not responding sooner, I'd not gotten notifications of the replies.