Subframe Connector dilemma

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cudaman51 said:
One thing that hasent been mentioned is whats your intended abuse plans for the car is directly praportional to the need for heavy duty conectors. 4spd auto strip street
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I don't plan on "abusing" my car, but I do plan on driving it hard and throwing more power at it over time. It's a 4 speed and will see 99% street with a chance of strip. Anything I do down there will be welded, even if they're officially bolt-ons.

I haven't been under my car in weeks because of my work schedule and I'm having a hard time imagining how those things hook on. Don't suppose you have any diagram of how they fit, do you?
 
I am with Dave on this one, I just don't see the us car tool ones doing as good of job as the other style. the floor isn't as strong as the box style connectors.

I have bought connectors from auto rust for my aspen and am very pleased with the quality of them. (except for when I cut my inner toe and had to have 3 stitches but that's my own fault!)

by the way its a 4spd 8 3/4 360 car.
 
Contoured subframe connectors continuously or skip welded to the floorpans as well as to the transverse structures (crossmembers) that intersect the front and rear longitudinals make the entire structure inherently stronger than those that simply tie in at the ends and float in space by stiffening the entire ground plane of the floor between the sill boxes. Connect these continuously integrated frame connectors to the sill boxes with torque box plates, either at the ends (like the factory), or continuously the full length of the floor, and the sill boxes and frame connectors will use the entire ground plane of the floor to form large box sections and increase the torsional rigidity yet again.
 
I agree with twofosho. I think the strongest starting point is 2x3x1/8th tubeing. ive thought about torq boxes but dont have a plan yet how to implement them. hears my 2x3 job with notched floor and flat bar pieces welded to the seat stifeners. I thought about ex shaped gusets tying the conector to the rockers. thats just a thought right now. hears some pitchers.

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twofosho said:
Contoured subframe connectors continuously or skip welded to the floorpans as well as to the transverse structures (crossmembers) that intersect the front and rear longitudinals make the entire structure inherently stronger than those that simply tie in at the ends and float in space by stiffening the entire ground plane of the floor between the sill boxes. Connect these continuously integrated frame connectors to the sill boxes with torque box plates, either at the ends (like the factory), or continuously the full length of the floor, and the sill boxes and frame connectors will use the entire ground plane of the floor to form large box sections and increase the torsional rigidity yet again.
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Bingo. The US Car Tools connector is a good design.
 
Here's another option when it comes to the subframe connectors. Picked these up from U.S. Car & Tool for around $180.00 shipped to the house.

Worked today (again) on cleaning the floor pan underside to prep it for the installation of these.

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To me looking at all of the above cudaman51 and BigSlim has the right idea. Those would have to be stronger than the others by far. The ones cut to the contour of the floor pans look awfully weak to me.

What about ride quality instead of torquing of the body? Do they make the car ride or handle better?
 
mullinax95 said:
To me looking at all of the above cudaman51 and BigSlim has the right idea. Those would have to be stronger than the others by far. The ones cut to the contour of the floor pans look awfully weak to me.

What about ride quality instead of torquing of the body? Do they make the car ride or handle better?
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I've seen several postings from owners who have had connectors of various origins installed and all of them were positive, including making the car seem quieter in addition to a tighter handling characteristics.
The US Car & Tool ones I have are a compromise between weight and strength; they're light but still thick enough to provide stability through strength. They'll be welded throughout their length to the entire middle section underside of the floor pan and the ends of the existing front and rear sections.
I'm looking forward to having them installed. I'll keep you posted on the results.
 
Gutted the interior today so nothing catches on fire when they weld in the new subframe connectors this week.
Found a bit of rust on the passenger side; cleaned it up with the wire wheel and will have it repaired while the GT is in the shop.

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Anything is better than nothing, the form fitting style would be all right for a street car.
Look at a 2X3 tubing this way..a carboard box is fairly strong when complete, some will hold an impressive amount of weight and have a strong structure BUT...cut the top flaps open and it's pretty easy to flatten or crush it.
I don't think those 3 sided ones pictured would be worth a whole lot with a set of slicks or serious horsepower. Even if the floorpan makes the 4th side of the box. 2X3 is the choice for a car with power, tied to the front and rear subframes and with the floor skins welded to them. Various people wil argue whether square or round tubing is better, I won't go there.
It's nice to be able to jack the car up with out the door gaps changing, and using a floor jack under them will lift the whole side of the car off the ground.
And that's something to remember if on a sloped surface, and suddenly you only have 2 points of contact to keep if from rolling!
As far as the ride quality goes, you might notice a little more stiffness, but the chassis not flexing might actually make it ride better in some situations. Still no worse than any A body ever was on a rough road.
Just my 2 cents worth.
(Added Later) Opposing opinions cheerfully considered.
Alan627b
 
I just posted this in another sub frame connector thread, but here it is again...I made my own. $50 in materials...Stronger than anything you could buy...
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I don't have pics of them being finished welded...So if your wondering, "hmm, there should be a weld there, and there, and there..." Well, they are all welded up now so, don't worry. I got it covered :)
 
Nicely done, Mopardude! Are you going to fully stitch weld all of it?
One other item I saw done, was a crossmember added above the pinion area with plate reinforcement, to give the pinion snubber something more substantial than the floor pan to beat on. Easy to do, beneficial to users of the pinion snubber.
Alan
 
alan627b said:
I don't think those 3 sided ones pictured would be worth a whole lot with a set of slicks or serious horsepower.
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The US cartool ones use the floor as a structural plane, they are very strong when installed properly. There are a couple of 9 second rides running them, no issues.

I have a few sets I made from 2x3 and a set of US cartools. I'd use either without hesitation.

I like using the 2x3 if I'm putting a rollbar/cage in a car. Give you a place to land diagonal bars behind the drivers seat. No landing plate required.
 
Check out the ones I made out of 1 1/2" x 3" x 1/8" tube steel. They are weld in but there is no cutting of the floor and you do actually weld to the floor pan as part of the installation.
I did make some mid span gusset plates to spread the load
Andrew

missiles frame connectors this forum
 
I got mine from Jegs. They are the form/weld type and didnt intrude into the passenger compartment. (I didn't wanna cut the floor of my 340/4 speed Demon). They were a top quality product. Jmo
 
Hey I gaurentee to weld to the floor pans youll eventually crack the pans when the chassis twists to the torque It will cracknext to the weld. They will work OK for a while,but will crack.
 
alan627b said:
Nicely done, Mopardude! Are you going to fully stitch weld all of it?
One other item I saw done, was a crossmember added above the pinion area with plate reinforcement, to give the pinion snubber something more substantial than the floor pan to beat on. Easy to do, beneficial to users of the pinion snubber.
Alan
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Yes everything is fully stitch welded now.
 
Hello, If 73dust340 decides on something esle, I'm interested in your used subframe
connectors from your 67 barracuda.
 
IMO, a long rectangular tube NOT welded to the floorpan is a lot more likely to twist torsionally than one that is. As far as the Cartool contoured types, even though they use the floorpan as the "top" of the box, the fact that the floorpan is not flat, but instead has vertical dimension changes adds to their resistance to torsional twist, and reduces shear stress on the floorpans.

Grant
 
OneOfMany said:
IMO, a long rectangular tube NOT welded to the floorpan is a lot more likely to twist torsionally than one that is. As far as the Cartool contoured types, even though they use the floorpan as the "top" of the box, the fact that the floorpan is not flat, but instead has vertical dimension changes adds to their resistance to torsional twist, and reduces shear stress on the floorpans.

Grant
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This is very true. You could use 22 gauge single sheet stock material that runs the length with a 90 degree break and weld it to the floor and it would be plenty strong. However the 2 x 3 stock is easy and cheap. I think the cartool is sano and looks virtually OE.
 
Lookin to tie frames this year,This thread has helped alot.Have not decided which way to go.
 
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