Subframe Connectors

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Bought stock for $25. Overlapped rear frame nice and welded to rear floor pan also,

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This is the one topic that consistently brings out what passes for snobbery on this forum.

Yes. If you have the equipment, space, experience, subframe connectors are a “cheap and easy” thing to create.

Somehow, the folks who proclaim this forget that not everyone wants to do this. Not everyone wants to have a Home Depot fabrication job under their prized car. Not everyone wants to attempt their own welding on their own car. Not everyone is confident that they’re not going to melt through their floors or start their car on fire. Not everyone has the luxury of hundreds of hours of welding practice. Not everyone wants to sit back and just assume their pieces are as working as good as they can be.

Plug and play/of the shelf parts are a known quantity, typically tested (or vetted by the market) for functionality with repeatable results. It might cost a lot more but please try to understand that folks may have good reasons for wanting to buy rather than fabricate.

It’s fine to mention the “DIY” alternatives but it’s not the only answer.
 
I fail to see how the bracing on those will really contribute much in the way of rigidity.
They look like a bolt in "better than nothing" connector. I don't like the idea of a round tube providing the strength. We all know what torsion bars do. LOL
 
These are really nice. A buddy just did a set in his Duster. A buddy of ours that welds a lot came in and knocked it out of the park.
Below is a link to just the connectors alone.
There full kits are really nice as well.
67-75 Mopar A Body Frame Connectors
US Car Tool ones make it look like it left the factory that way. Nice stuff for sure.
 
US Car Tool ones make it look like it left the factory that way. Nice stuff for sure.
Here's a vid of US Car Tool install. There are many others. The guy is building a charged small block Valiant. Been following his videos. Pretty good stuff.

 
This subject gets argued every few months! with more determination than discussing oil!!
Yep. The only thing you can do is categorize it. Which is cheapest. Which looks the best, Which is easiest to install. But the debate is always about which is strongest. Who knows and how could you test it unless you are an engineer in a lab.
 
Yep. The only thing you can do is categorize it. Which is cheapest. Which looks the best, Which is easiest to install. But the debate is always about which is strongest. Who knows and how could you test it unless you are an engineer in a lab.

As I understand it is because the floor is a structural part of the chassis, the weakest connectors are bolt ons.

Then the weld in connectors.

Then connectors welded TO the floor.

And the strongest is connectors welded THROUGH the floor.

The last one is the biggest PITA to do because the fitting has to be very close. IIRC I was told no more than a 1/32 gap. On a long piece like that fitting it will take significantly more time than welding it out.

Again, as I understand it, welding it through the frame changes the way the floor transfers and transmits the loads. The floor actually pushes on, and pulls against the tube rather than pushing and pulling on the welds if that makes sense.
 
That is how I understand it. Being that the unibody will flex a lot, anything that helps stiffen the chassis is a plus. Considering the length between subframes, this can be a lot, all of the will bow and twist under hard forces. The better connected the frame connectors, the less flex there will be on the floor and the entire car. The less flexing, the more power you get to the wheels. More flexing, less power. It just gets wasted.

The only thing you can do better is to introduce a full frame or and entirely new chassis to put the body on. For us regular guys, if you can run or tie the frames right through the floor and then weld it together as close to as a singular piece the better.

A flexing body is your enemy and a waster of power.
 
Yea! I like watching his channel. Just a regular guy having fun and sharing it so you can take the ride along with him. Very cool.
 
Those of you making your own, what are most using? 2x3? What thickness? I assume 1/8"?

I used .120" wall 2 x 3 on my 66 Dart, with the 3" side vertical (through the floor).

On my 68, I used .065" wall 2" square tubing and pushed it through the floor as well, then scribed where it stuck through, and sectioned that part out so it doesn't stick through and the carpet lays flat.

There's a bunch of way to skin this cat for sure.
 
Maybe .03 % of our members can pull the front wheels . So I am not sure how important ultimate strength is .
 
Maybe .03 % of our members can pull the front wheels . So I am not sure how important ultimate strength is .


It’s not just pulling wheelies. It’s the load applied to the chassis through the front spring mounts and all the suspension points. All that load is transferred through the floor and up the A and B pillars.

That’s why a hard hooking flexible chassis will crack the B pillar, break the side windows out and start moving the A pillar around.

BTDT and it ruins the car.
 
It’s fine to mention the “DIY” alternatives but it’s not the only answer.

OK, another alternative. When I bought my frame peices I had them cut to exact lentgh $25. How much would a bodyman charge you to weld them in? He wouldn't have to weld them to the floor like I did.Still stronger than bolt ins IMO . Bolt ins $500? It wouldn't hurt to ask.

Not everyone wants to have a Home Depot fabrication job under their prized car.

Not everyone wants to have a Home Depot fabrication job under their prized car.

Hope that wasn't directed at me. In the end I thought they came out good.

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It’s not just pulling wheelies. It’s the load applied to the chassis through the front spring mounts and all the suspension points. All that load is transferred through the floor and up the A and B pillars.

That’s why a hard hooking flexible chassis will crack the B pillar, break the side windows out and start moving the A pillar around.

BTDT and it ruins the car.

Ok .. including those cars we are now up to 1%

And if my car is that strong I would weld all the sheet metal seams .
 
OK, another alternative. When I bought my frame peices I had them cut to exact lentgh $25. How much would a bodyman charge you to weld them in? He wouldn't have to weld them to the floor like I did.Still stronger than bolt ins IMO . Bolt ins $500? It wouldn't hurt to ask.

I don’t think there’s a darn thing to say negative about this approach but let’s be clear, everyone’s home brew install will be different. There’s a lot to be said for tried and tested off the shelf parts. To some people, that repeatability is with the cost.

Hope that wasn't directed at me. In the end I thought they came out good.

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Not at all. Yours looks professional and clean. Not all of us work that neatly and the experience that it takes to do this stuff doesn’t just happen over night. Welding is an art.

If you’re one of those people who just picked up the skill, you should keep in mind that this is not a common experience. Boogery, chunky welds (that don’t last) are the norm for beginners.

I bought off the shelf Mopar Performance connectors and US Cartool torque boxes. Are they the ultimate/optimal solution? Some skills could have saved some money too but they’re done and The money I paid to the professional welder was well spent, IMO.
 
I'm not really trying to argue about it LOL, but more so to point out how easy it is and maybe encourage someone to save a bucket load of money on what amounts to be a straight piece of metal...
For 5 to $800 someone could buy the material the welder the grinders and everything elseand for that matter pay for a class to learn how to weld LOL.. if watching a few YouTube's wouldn't get you there..
I just mention it as an alternative and give pictures encouragement and will answer any questions...
Look at mine in the pictures. I had just but the welder and wasn't very good with it yet. I was barely off the ground with the jack stands and welding upside down and it was a mess. They've function perfectly and there's no cracks on the welds.. and all these years not one person has laid on the ground and looked under the car and said oh God look at those welds!!!..
Remember those bolt-on ones aren't just a piece of cake... You definitely have to Jack the car way up in the air so you can work under there. You got the drill multiple holes that line up through both sides of the thin walled Factory box tubing.. those holes better be drawn very close to the circumference of the bolts going through them or else there's going to be movement. The exact thing you're trying to stop... I would suspect after years of twisting those bullet holes are going to start wallering out because the factory metal is not that thick... I.e. pretty much welding them is the only way to make them solid and that's basically what we're going for here.. even if they're bolted up firm feeling from one end to the other as the body twist there's a lot being expected of bolts going through sheet metal...
no I can see if you're building a show car and expecting to drop mirrors on the ground for people to see underneath...
And what it boils down to is it's not my money spend away LOL...
A cheap alternative would be to get the two pieces of 4 ft by 1 and 1/2 inch by 2 and 1/2 inch metal stock, cut the end off like I showed in that picture. That would require you to buy a $14 Harbor Freight cutter grinder. And then cut the 3 cuts on each side of the frame to open it up in the back. Slide the end of the frame connector in there and push the front end up against the front with your jack and shoot a self-tapping screw through the bottom of it into the frame. So they're pretty much set. Then drive it up to a muffler shop and have them welded up..
 
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