Through the floor subframe connectors: I beam vs 2x3x0.120

[96Mustang460cid]

I was watching Dave's DVD's when something popped into my head...

2"x3"x0.120" rectangular tubing weighs ~3.9 lbs/ft and has an second moment of area of 1.42 in^4.

In contrast, S3x5.7 I beam weighs 5.7 lbs/ft, but has a second moment of area of 2.52 in^4.

It weighs 46% more, but is 77% stronger. I spent a few minutes looking for the smallest I, W, ect beam and the S3x5.7 is what I found. If something smaller is available, it seems like it would be a good option.

Is the 2x3 considered adequate or is this an area that could benefit from additional strength? I understand that the I beam is not as rigid in torsion as the 2x3, but isn't cross bracing recommended anyways?

Just a thought :).

Have a good day!
Michael

[John_Heard]

I haven't seen square tube frame connectors bent, I'd have to assume they are adequate for the job.

However dare to be different - I Beam would certainly be something unique

[supernova]

I-beams are not ment to be twisted which is what happens to the frame connectors and or the frame itself. I have 2x3x.120 sq. tubing through the floor. The only way to be strong enough. I-beams twist! out of all the years of being around drag racing I would have thought if I-beams were better then that would be the norm. Not so. Do yourself a favor and stick with the norm.

[John_Heard]

Shhh dang it, those mustangs need the extra weight!!!

[supernova]

Oh crap! sorry John. Stangs do need more weight!!!!!!!!!!!!!!!!!!!

[John_Heard]

Just messing with ya Mike...

[96Mustang460cid]

Thanks for your input guys!

Have a good day!
Michael