1973 Camaro - Autocross / Street Car project

[byndbad914]

now at least the discussion begins to involve sizing of tubing and orientation of load discussions. It isn't just "square is better than round" sort of thing. Additionally consider weight when you use 2x2 box v. 2" round, etc and the efficiency that comes from actually doing P/A calcs, buckling if that is critical, etc. Like I said, using square tubing isn't bad, but a general statement like square tubing is better than round is a too general IMO and shouldn't be assumed some sort of rule of thumb. Depending on the length of the section then torsional rigidity also comes into play.

If you now consider all your formulas and design by weight and not just size (which should be a primary consideration in any race car even one with a 3100lb weight reqm't) then you won't use 2" square over 2" round.

Now in some instances like framing out a car it can be beneficial to use rectangular tubing, oriented correctly to have a narrow beam fitment where you need to drop seats between beams v. round tube that is fatter than that orientation requires... if I could have gotten rect chromoly in the size I calc'd I wanted in my racecar I would have boxed my cockpit with it but was stuck using round (I used Finite Element Analysis software to lay out all of my stuff to compare stresses, torsional rigidity, etc in design before I had my chassis built).

Back on topic, again diggin' the car so keep the pix coming!

[MtotheIKEo]

Originally Posted by byndbad914

Who on Earth told you that? I am not saying it is bad to use square tubing, but what you just stated is based on something other than engineering... generally speaking a square is one of the worst shapes, hence why you see a lot of round columns for compression members like bridges across the nation and engineers use words like "triangulate" - make sure to make every square a triangle at some point. Not too many square submarines out there

Actually, a square beam is stronger in bending and as a simple beam, using engineering equations. Both or these failure modes are based on the members moment of inertia, and a square tube has a higher value.

And triangulation refers to frame nodes and tube intersections, not the material shape.

[73CPCAMARO]

Thank you.

[byndbad914]

I just deleted my response actually - no hijack

[73CPCAMARO]

Here are photos showing the front structure near completion. The cross bars are still to be installed.

[70rs]

Very nice Brian!

[Sandbagger]

Is the subframe welded solid to the body ? Is it still possible to square the frame up with the body ? may be a better way of wording it
Sorry if it was already discusssed .

[73CPCAMARO]

Originally Posted by Sandbagger

Is the subframe welded solid to the body ? Is it still possible to square the frame up with the body ? may be a better way of wording it
Sorry if it was already discusssed .

The subframe is bolted to the body at the normal location with metal bushings instead of rubber. The bottom of the car has a subframe connector set up that is all welded together, tying it in with the cage assembly. Everything was squared up already.

[tones2SS]

Very nice work guys!!

["Swoosh"]

wow awesome fab work