Subframe Connectors and unibodies

[torredcuda]

So every unibody car with a fulll roll cage (which is not only for safety but adds a LOT of rigidity) will tear itself apart at the spot welds? He knows his stuff most of the time but wrong on that. I can`t watch his videos though, every one is 30+ minutes of rambling when he could have made his point in less than 5 minutes.

 

[Kern Dog]

A lot of the guys with YouTube channels are like that. Sometimes it gets annoying having to skip through all the drivel to get to what is described in the title.

 

[VANDAN]

I haven't followed this post, but We installed the US Cartool Frame Ties, on my '63. My Only Regret, is we didn't add the Torque Boxes. We'll be using those on the '65 Project. GOD Willing !!!

 

[eldubb440]

I haven't followed this post, but We installed the US Cartool Frame Ties, on my '63. My Only Regret, is we didn't add the Torque Boxes. We'll be using those on the '65 Project. GOD Willing !!!

View attachment 1789543

Dan, I love that car and you almost never show us any pictures

 

[RemCharger]

Yup there goes any pictures of my junk..



Lol car that is

 

[ckessel]

Stop it, my Hemet won't fit anymore

Hemet is a town in Riverside county California. I guess you fell over from the likes and knocked the L out of you.

 

[Photon440]

Hemet is a town in Riverside county California. I guess you fell over from the likes and knocked the L out of you.

Hemet is where Bladecutter resides.

 

[j-c-c-62]

Hemet is a town in Riverside county California. I guess you fell over from the likes and knocked the L out of you.

Tpugh crowd tonight. And yes, that p was intentional. 

 

[Kern Dog]

I let it slide because he built a really great dashboard.
Skilled people get a pass for the occasional mistake. Dipshits get no favors.

 

[j-c-c-62]

So every unibody car with a fulll roll cage (which is not only for safety but adds a LOT of rigidity) will tear itself apart at the spot welds? He knows his stuff most of the time but wrong on that. I can`t watch his videos though, every one is 30+ minutes of rambling when he could have made his point in less than 5 minutes.

Yes, some videos are tortuous. but they have a tough task to ascertain what their audience has as an across-the-board mentality, and if a single item gets overlooked it's easy for anyone, including me to chime in and point it out. Maybe they need to have selected one of three levels novice, xxxxxxxx, and expert, at the start of the video to get ethe audience all on the same page, but have no idea how to implement that. It's hard to assume what the listener knows to begin with as a base level. I will watch it later.

To your comment about spot welds failing, there is some merit to that thinking, the problem is, good SFC connectors ( I exclude anything bolt on, round or three side contoured in that description) are so much more rigid than the existing chassis, they relatively have no give, and all/most of the forces in that area of SFC, the chassis would normally absorb by flex and only partly get forces transferred elsewhere, and now with SFC those forces are likely transferred elsewhere to a smaller more confined remaining area, to those remaining same number of spot welds are now tasked with greater loads. If those loads are high enough and repeated enough. they should be expected to eventually fail. There is a big "if" there, and we are not even considering here a car already weak with extreme mileage, salt corrosion, rust, very high hp, any accident history or abuse to add to the equation. Would torques boxes help reduce that possibility, not in my eyes, they actually might worsen it as it just makes the same area the SFC are in even stiffer, but not by much because well designed good SFC do a pretty good job there all by themselves. There are ways to mitigate spot weld failures in any case.

Hope I did not omit any "L's".

 

[66 Sat]

To your comment about spot welds failing, there is some merit to that thinking, the problem is, good SFC connectors ( I exclude anything bolt on, round or three side contoured in that description) are so much more rigid that the existing chassis, they relatively have no give, and all/most of the forces in that area of SFC, the chassis would normally absorb by flex and only partly get forces transferred elsewhere, and now with SFC those forces are likely transferred elsewhere to a smaller more confined remaining area, which loads those remaining same number of spot welds now with greater loads. If those loads are high enough and repeated enough. they should be expected to eventually fail.

Here we go....
So if the bolt on connectors are not "good" (contrary to my personal findings), then they wouldn't cause any potential stresses to the existing spot welds...which would then make them good after all?

 

[j-c-c-62]

Here we go....
So if the bolt on connectors are not "good" (contrary to my personal findings), then they wouldn't cause any potential stresses to the existing spot welds...which would then make them good after all?

You are exactly right. One could also use rope, and all the spot welds would also be even happier.

I watched the video, I'll ignore the flip commentary and production quality.
First, I have yet to confirm here convertibles with torque boxes had an extra and/or heavy-duty internal reinforcement in the sills vs non convertibles.
I also question whether the factory installed any "torque boxes" on the rear leaf hangers for Nascar.
The video basically indicates OEM torque boxes were a factory band aid to only reduce flex/stress in an overloaded chassis in a very specific area and the design was limited because a stiffer solution would cause weld problems elsewhere. Flex is only needed/allowed because the original design/build is lacking. That is actually sad and likely cost driven.
Bottom line, original load path from frame rails thru the sills to the front frame rails with or without torque boxes is a very inefficient engineering design, always has been, and according to the video was mainly to maintain rear leg room, and torque boxes were a cheap partial fix, that the aftermarket has provenly solved for years now with full depth welded SFC.
Surprised to see the important design shortcomings of the contoured 3 sided SFC mentioned.

 

[icetech]

I haven't followed this post, but We installed the US Cartool Frame Ties, on my '63. My Only Regret, is we didn't add the Torque Boxes. We'll be using those on the '65 Project. GOD Willing !!!

View attachment 1789543

That is beautiful... I have the connectors installed on mine and the torque boxes sitting in a corner.. it's on the list of "Eventually" I don't make enough power that it matters