subframe connectors questions

-
moparmat2000

moparmat2000

Well-Known Member
Joined
May 13, 2010
Messages
21,012
Reaction score
11,237
Location
Grand Tetons
Hi Y'all

Im getting ready to put in subframe.connectors on my 67 cuda. I have some mild steel that is .083" wall thickness. Its 2"x3" rectangle. I was wondering if this is thick enough. The stock framerails, and transmission crossmember are this thickness. I also was concidering laying the tubing to where its 2" tall and 3" wide to clear the rear floor with minimum intrusion , and allow my parking brake cable to clear. I got the idea from bigblockdart.com, but they are using .125" tubing.i think this may be a bit thick.
Any ideas?
Thanks
Matt
 
moparmat2000 said:
Hi Y'all

Im getting ready to put in subframe.connectors on my 67 cuda. I have some mild steel that is .083" wall thickness. Its 2"x3" rectangle. I was wondering if this is thick enough. The stock framerails, and transmission crossmember are this thickness. I also was concidering laying the tubing to where its 2" tall and 3" wide to clear the rear floor with minimum intrusion , and allow my parking brake cable to clear. I got the idea from bigblockdart.com, but they are using .125" tubing.i think this may be a bit thick.
Any ideas?
Thanks
Matt
Click to expand...

I made mine out of .085 2x3 laying flat and couldn't be happier with them.
Did it for the same reasons you mentioned also (brake cable and brake line and it worked out really well.
 
moparmat2000 said:
Hi Y'all

Im getting ready to put in subframe.connectors on my 67 cuda. I have some mild steel that is .083" wall thickness. Its 2"x3" rectangle. I was wondering if this is thick enough. The stock framerails, and transmission crossmember are this thickness. I also was concidering laying the tubing to where its 2" tall and 3" wide to clear the rear floor with minimum intrusion , and allow my parking brake cable to clear. I got the idea from bigblockdart.com, but they are using .125" tubing.i think this may be a bit thick.
Any ideas?
Thanks
Matt
Click to expand...

anything is better than nothing. i used 3x3" 1/8" wall on mine and the car will sit on 3 jack stands and the doors still open like a new car.
 
well since this is going to be a road race car / street car and not an all out drag car i am not so much cioncerned with the twisting forces of the front end lifting under accelleration on a drag strip. i am more concerned with the side to side chassis twising forces from a heavy duty suspension and a road race type of course scenario.

i know that if i mount the tubing 3" high and 2" wide it will result in a stiffer chassis for drag racing, but if i mount the tubing 2" high and 3" wide will it result in a stiffer chassis torsionally (twisting for road race)

mounting the tubing 3" wide helps installation to the rear framerails, with brake line clearance, rear foot pan clearance only 1/2" intrusion into the foot well, and parking brake cable clearance. but will .083" wall thickness be enough? if not should i purchase some .125" 2"x3" and mount it sideways?

id like to use what i have .083" 2"x3" since it was free, and is the same thickness as the stock framerails.

any ideas or am i overthinking this whole thing here? its a ***** to do this and i only want to do this once. i imagine its really a ***** if i got to cut it all back out and go thicker later.
matt
 
I really don't think you will have to worry about it Matt.
Most of the aftermarket rails are not as thick, and nowhere close to 2x3.
Yours is only 2 thousands thinner than mine, and mine are nice and solid.

Also isn't the cuda a little shorter than Darts?
 
Mine are 2x3, thru the floor, car is caged so it made attaching the cage easier. Can put a jack under the side of the car and jack up one side.....and the door still opens....
 
Prob gonna add triangular gussets in the front where it meets the crossmember to spread the load a bit. Overlapping it in the rear and tying it in at the rear floor pans makes it plenty strong in the back.
 
Can you post any pictures from your connectors.

mine duster dont have any but doors still open and close easy when car is on stands,
1,2,3 or 4
 
Don't really need to gussets. Fishplate it to spread load and you're good.

083-090 is fine as well. Mine that are 2x2x.083

frameconnectors.jpg

frameconnectors002.jpg

frameconnectors001.jpg

frameconnectors003.jpg
 
moparmat2000 said:
well since this is going to be a road race car / street car and not an all out drag car i am not so much cioncerned with the twisting forces of the front end lifting under accelleration on a drag strip. i am more concerned with the side to side chassis twising forces from a heavy duty suspension and a road race type of course scenario...
Click to expand...
Do you plan on accellerating out of the turns with it? All the same torsional stresses are going to be a factor as well. Cars don't really bend in 1/2 as much as they twist. Whether is straight line accelleration or out of the corners they all want to twist. I don't know how hard you plan on stressing the car or what kind of power you plan on making, .083 may be plenty, but a length of .125 mild steel isn't that much money. I knew a guy who used .083 m/s in his connectors on a Duster that ran 11.50s & didn't seem to have any problems, but... You may want to consider the headaches if you install the .083 & it doesn't work & you have to re-do it. Just saying...
 
JPEG subframe connectors
i had some small scrap pieces of .083 2X3 that i tacked together to make a mock up of what i want to do. how you tie it together at the front end is pretty self explanitory, so i will show a majority of my pix at the back end. i think i am going to buy some .125" thick 2X3 tubing to actually make the connectors i will be welding in. got pix cant figure out how to post them

heres pix
matt
 
Don't over think this. You will be absolutely amazed once you have them in. Look at Rob's pictures posted above.

I did basically the same thing on my car and I can jack it from anywhere and the doors still open and close from any position. That in of itself is true testament that they are doing their job.
 
You can whip up a channel bracket like I did.

If you use 2x3x.120 tube, laying the wide side flat, you can open the 3" side and have it slide over the rear frame section. Drill some holes for plug welds and weld your edges. There is usually a small gap at the rear because the frame section is not 1.75" tall.

Here's a 2x3 install AbodyJoe did to give you an idea.
http://www.forabodiesonly.com/mopar/showthread.php?t=132668
 
These are 2 x 3 x .125...you can see what Crackedback said about the channel bracket at the top...

Basically cutting out the inside of the box...
 

Attachments

  • IMG_0666.JPG
    79 KB · Views: 393
Hmmm If you shoved a floor jack under the connector at mid span and jacked the whole side of the vehicle up... Which way would the tubing be less flexed or likly to buckle at the jack ? My guess is with the 3" vertical. Doesn't matter really, just dont jack there. LOL
Good luck which ever way you go
 
what i meant about cant figure it out was how to send my pix of my progress. i cut slots in the rear foot wells and cut off the tapered front edge of the rear framerail, i will be using .125" 2X3 and lying it on its side, and opening up the top at the back to slide it over the framerails. at .125" wall thickness i am sure you can jack the car up from the subframe connector. thats mucho thick. i had some .083 2x3 lying around i used as a template for cutting everything out. for the taper at the rear framerail, i am going to notch slots in the tubing and draw it in, and reweld it. this way it fits tightly to the framerail. just wish i could figure out how to post my pix. i like the way i cut and dovetailed the rear framerails, now i cant wait to get the thicker tubing and weld it in for good. very similar to 70aarcuda did in his pix.

thanks to all of you for the ideas and pix. i am headed towards no chassis flex on my cuda, just wish i could figure out how to show you my pix.
 
You must log in or register to reply here.
-

Back
Top