Front sub frame reinforcement

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Martythetrimmer

Martythetrimmer

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I have read a lot about early A bodies flexing between the sub frame and fire wall. A lot of people run a bar from the front of the sub frame back to the fire wall to stop this. It would work well but isn't very cosmetic, looks good in a race style car but not so much in a show based one.

It said they move along the line of the green arrow.
View attachment 1.01.jpg

My idea is to weld a plate in this green area to strenghten it.

View attachment 1.02.jpg

Then weld in a bar, 2" x 1", from the shock mount back to the reinforced area.

View attachment 1.03.jpg

The load on the sub frame is applied via the lower control arm directly below the shock mount so while a bar from the front of the sub frame would be stronger I think bracing the shock tower back to the firewall would have a great affect in a street car.
Has any of you thought of or even tried this? Any thoughts on it before I start?

Marty
 
Marty,
your arrow tells it all. Reinforce in these areas and 16 Ga sheet metal should probably do.
Andrew
 

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So you wish to transfer the load into the shock mount/upper control arm mounts?

Weld a landing plate vertically on the firewall. Tuck a round bar tight in the in the inner fender bend, holesaw the shock tower vertical section and land it on the side of the frame rail about 6" in front of the upper control arm bracket

This is on 69 Dart so you have some different inners. But gets the idea.

mydart586.jpg


mydart574.jpg


You don't need to land them this far forward. It's really the best option to support the front.
 
crackedback said:
So you wish to transfer the load into the shock mount/upper control arm mounts?

Weld a landing plate vertically on the firewall. Tuck a round bar tight in the in the inner fender bend, holesaw the shock tower vertical section and land it on the side of the frame rail about 6" in front of the upper control arm bracket

This is on 69 Dart so you have some different inners. But gets the idea.

mydart586.jpg


mydart574.jpg


You don't need to land them this far forward. It's really the best option to support the front.
Click to expand...
Hey Crackedback, can you show pic's of the rear mount? This looks interesting!
 
Not mine, it's deepockets car. He's mostly on moparts.

Bars land on the roll cage a-pillar bar, going through the firewall.

You can run them higher and tighter than this set up. Where it would go through the firewall, weld a plate.
 
dont know if this is an issue on the 73 dart, but i was looking for a way to reinforce my front end with out putting in a full cage and i just found it. thanks for posting this and thanks for the pics crackedback!
 
crackedback said:
So you wish to transfer the load into the shock mount/upper control arm mounts?

Weld a landing plate vertically on the firewall. Tuck a round bar tight in the in the inner fender bend, holesaw the shock tower vertical section and land it on the side of the frame rail about 6" in front of the upper control arm bracket

This is on 69 Dart so you have some different inners. But gets the idea.

mydart586.jpg


mydart574.jpg


You don't need to land them this far forward. It's really the best option to support the front.
Click to expand...

I am doing this exact same thing to the 67. The forward bars will come off the cage under the dash thru the firewall and land somewhat like that. Good picture!
 
crackedback said:
So you wish to transfer the load into the shock mount/upper control arm mounts?

Weld a landing plate vertically on the firewall. Tuck a round bar tight in the in the inner fender bend, holesaw the shock tower vertical section and land it on the side of the frame rail about 6" in front of the upper control arm bracket

This is on 69 Dart so you have some different inners. But gets the idea.

mydart586.jpg


mydart574.jpg


You don't need to land them this far forward. It's really the best option to support the front.
Click to expand...

What diameter and how thick of wall tubing would be sufficient for this? Do you think 1" .095 DOM would work?
 
John,

I'd use the same tube as a roll cage, 1 5/8 .083 CM tube if CM is your choice.

I would think a 1" .090-.100 bar would be OK, just not as stout.
 
crackedback said:
John,

I'd use the same tube as a roll cage, 1 5/8 .083 CM tube if CM is your choice.

I would think a 1" .090-.100 bar would be OK, just not as stout.
Click to expand...

I am just thinking to save room for the front tire. Even after my frame connectors are in there is still quite a bit of flex from the firewall forward in my car. I will be doing this and a rad support when I blow my car apart. I just have access to a 1" bender that can do .095"
 
The cage in my car has snout bars similar to those posted above except they run thru the inner fender and are attached to the top of the oe frame......
 
inkjunkie said:
The cage in my car has snout bars similar to those posted above except they run thru the inner fender and are attached to the top of the oe frame......
Click to expand...

I know a cage would be best, but I am just wanting to stiffen her up a little more.
 
Badart said:
I know a cage would be best, but I am just wanting to stiffen her up a little more.
Click to expand...
The way mine was done would work with out a cage as well. Be much easier to see in pictures than for me to explain, if you are interested let me know and I will get some pictures of it......I know what you mean about stiffening things up. I picked the front of my car up with a hoist attached to the bumper mounts and you could see the front frame sections moving at the firewall junction. A good portion of the seam sealer fell off when I did this.....
 
inkjunkie said:
The way mine was done would work with out a cage as well. Be much easier to see in pictures than for me to explain, if you are interested let me know and I will get some pictures of it......I know what you mean about stiffening things up. I picked the front of my car up with a hoist attached to the bumper mounts and you could see the front frame sections moving at the firewall junction. A good portion of the seam sealer fell off when I did this.....
Click to expand...


May as well post them here. I am interested.
 
Dang. Went out and found some 1" dom in the garage and it's way to small. Going with 1.5" for sure.
 
Mine is very similar to what crackedback posted. Keep in mind that my car does have a cage but don't see why you could not weld a plate to the firewall instead of running thru it. Mine is tucked up a bit higher.....computer keeps crashing when I try to upload pix, will try again tomorrow....
 
I was gong todosome thing like this to my Duster drag car and run a motor plate betwen them. Was going to run them through the fire wall to the cage. This car has the inner fenders removed but same can be done with them. Hit the shock mount for extra strangth in that area.
 

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I did the xv mod and rad support mod on my Duster...looks good added a ton of strength along with the through the floor subframe connectors. However my 1.5 dom tube appears as though it is going to make contact with my 245/40/17's. I am still about 6 months from verifiying this for sure. I may have to cut them out.
 

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we did some further strenghtening by gently peening the inner fenderwell engine side, at the shocktower. We hamered the sheetmetal down to make full contact with the upper shock mounts in the wheelwell and then welded it solid. He did a really pretty job and we were not gonna metal finish it , but now upon reflection, I think I am going to make some patches to weld over the grooves in the engine bay, to make it pretty again. Once the car is together, I intend to make a "Monte Carlo" bar You know the stuff they had on vintage gt350's.
 
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