I want to put subframe connectors in The Charger and want to get a few opinions on my options. I've made and welded them in 2 A body cars using 3x3 .120 wall tubing. I cut them to the contours of the floorpan and then REboxed the sections where they were cut away. The Charger front frame rails run at an angle towards the torsion bar crossmember, so I plan to simply run the connectors in a straight line from the rear frame rails forward as I have seen elsewhere. The rear frame rails appear to be 2 1/2" wide, so the 3x3 tubing may also work here. I have seen some ads with connectors that are "Laser Cut" to match the floorpan, but it seems to me that there is probably more stiffness with a boxed connector rather than a 3 sided one.
Opinions?

Your strongest frame connector will be a rectangular box iron with 4 sides, with the widest beam side being vertical with the other frame members in the vehicle, if cutting the floors doesn't bother, then cut the floors so that the connector protrudes thru the floor, once welded from both sides, they will appear as the laser cut floor matching units sold, only stronger, you could easily fit 2X3 or 2X4 inch box iron connectors doing it this way

Do you have inboard springs? I like the way the Hotchkis connectors are, but make my own.

My springs are in the stock location. My thoughts are to fab up the connectors similar to these that I made:

I also intend to make some Torque boxes and weld them in afterwards. I was just curious as to what other members have done.
Dayclona: Am I to understand that the strength in the connectors is greater in the VERTICAL plane, I.E. in the case of a 2x3 member, the 3" section being vertical? If so, this is the same principle that all truck and car frames share, boxed or open. Curious though since I've never seen these cars sag in the middle like an overloaded burro. (Strange reference, I know) I thought that the intended gain was to resist twisting in the middle, and the welded connectors are a big help in reducing the deflection between the front and the rear. I have seen cars with bolted connectors that are installed with the wider section in the horizontal plane and wondered if they were effective at all.

Here's my take. For cars with stock spring hangers the loads are being transmitted at that location. That is why Chrysler made torque boxes, to connect the thrust to the frame rails. By using the Hotchkis style, you are strengthening the unibody in the right areas and eliminating the need for torque boxes. For cars with inboard springs (in the framerails) putting the connectors in line with the rear frame rails does the same thing. I believe that on most cars the spring hangers line up with the front frame rais as well.

If you fastened pieces of 2 x 4 lumber in there it would still be an improvement. I've seen guys use single round tubes, double smaller round tubes, 1 x 2 cold rolled rec. tubing , 2 x 2 square and 2 x 3 rec. as well as the laser cut stuff. When you get up to 2 x 2 square, 2 x 3 rec. or the laser cut pieces you'd have a hard time telling the difference unless it were a full-time drag or autocross car - in which cas you'd probably have a bit more tubing inside helping to keep things from twisting.

I did go ahead and weld in the 3x3 frame connectors and torque boxes. The car handled great before but afterward, the ride felt more solid. The car soaked up dips and bumps with fewer rattles. It was quieter. I fully endorse this upgrade to anyone except those with OEM correct restorations.

I had a local shop fabricate some for the road runner and they did make a difference on how the car rides and reduced squeaks.

Quote:
Pics if ya got any. i'm looking to do this when it warms up on my RR"


I was finally able to take some pictures.

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