Subframe connectors

[MomsDuster]

Ok folks, Opinions on the available bolt in and weld in subframe connectors for A body's.

 

[Bad Sport]

Make your own. Much cheaper and just as effective. I made mine out of 2"x3" rectangle tube, cut to fit and welded them in.

Cost, about 35 bucks.

 

[Valiant63]

The bolt in frame connectors aren't worth a crap unless you're going to weld them in.

 

[TrailBeast]

Make your own. Much cheaper and just as effective. I made mine out of 2"x3" square tube, cut to fit and welded them in.
Cost, about 35 bucks.

If there is reasonable access to a welder or someone you know that can help, this is def the way to go.
The only connectors worth a dang are home made or the ones that weld to the entire floor pan.
The 2x3 tube laying down slips right over the rear channel too.

The bolt in frame connectors aren't worth a crap unless you're going to weld them in.

Even then they are only worth a partial crap because of the material they use.
Way too flimsy in my opinion.

Here's the layout for when I did mine if it helps or gives any ideas.

 

[Valiant63]

I should have said that I always make my own and weld them in.

 

[70wayfarer]

Make your own. Much cheaper and just as effective. I made mine out of 2"x3" square tube, cut to fit and welded them in.

Cost, about 35 bucks.

X2

 

[MomsDuster]

Thanks for the input. Making them didn't even cross my mind!

 

[Bad Sport]

Thanks for the input. Making them didn't even cross my mind!

If you have a way to cut and fit, and then weld them in, it is a very good alternative.

There ARE certain things that need to be followed before doing any welding.

 

[Bad Sport]

Here are a couple of pics.

 

[Bad Sport]

Like said, it cost me about 35 bucks for the material. I may have misspoke, they are 1 1/2 inch by 3 inch.

It is imperative when installing them to make sure they fit perfect. Get the car on stands, make darn sure it's level, AND open and close the doors BEFORE doing any welding.

On the front end, you will want a piece of flat bar welded to the tube, and then weld around that flat bar to the subframe.

It was a pretty simple job even doing it on stands.

 

[MomsDuster]

I assume your referring to welding safety, pulling interior, fuel system removal and or clearance etc. I'm all ears as to any other info or advice.

 

[MomsDuster]

LOL your a mind reader! Thanks!

 

[Bad Sport]

I assume your referring to welding safety, pulling interior, fuel system removal and or clearance etc. I'm all ears as to any other info or advice.

Yeah, no need to do any thing inside, unless you design them for going through the rear floor. I'm not sure that's 100% necessary for a street driven car with moderate upgrades. All out race, then yes.

And yes to the fuel system, just use common sense there, you won't be real close to the tank, but will be near the lines on the passenger side where the fuel line runs.

You will notice a difference after installing them, I noticed as I was backing out of the garage and driveway.

 

[TrailBeast]

You will notice a difference after installing them, I noticed as I was backing out of the garage and driveway.

Me too, a HUGE difference felt right away.
They cut down on the body and interior pops creaks and groans also.

 

[ScampMike]

IF you plan to buy not build them - on a street ONLY car, the bolt in ones are fine - if however you plan to do any kind of "spirited" driving (ANY type of racing) - weld in type ALL the way

 

[MRGTX]

Per advice on this forum, I'm about to order the units from US Car Tool.

For those of you who hired out the welding job, what did this run you?

I just called the one local shop that advertises this kind of work and they refused to even ballpark an estimate without seeing the car and the parts...which is understandable to some degree.

Without any concept of what this will labor run, I've been tempted to order up the Mopar Performance bolt-in connectors but it seems unanimous that people believe these are worthless.

 

[belmateo]

The bolt in frame connectors aren't worth a crap unless you're going to weld them in.

And they do not line up correctly at the front!

 

[jbc426]

Per advice on this forum, I'm about to order the units from US Car Tool.

For those of you who hired out the welding job, what did this run you?

I just called the one local shop that advertises this kind of work and they refused to even ballpark an estimate without seeing the car and the parts...which is understandable to some degree.

Without any concept of what this will labor run, I've been tempted to order up the Mopar Performance bolt-in connectors but it seems unanimous that people believe these are worthless.

I've installed 2 sets of the US Cartool floor huggers. They are very effective. A few tricks I learned along the way aside from the commonly acknowledged need to have the car resting on the suspension are as follows.

Use a bottle jack to hold the bars in position firmly. Grind the high spots from the bars to fit the floor as close as possible. I use a large rubber mallet to massage the floor downward to meet the low spots on the bars. Don't get carried away though. Better to some more grinding than to deform the floor significantly.

I stich weld them in and carefully hammer the floor closer to close the gaps. Seal the welds with 50 year black, paintable roofing sealant. Look on-line for guys that do on-site welding by the hour. It should only take them a few hours once you have them fitted well. Fitting can take the better part of the day for the pair of bars, or a few hours using the rubber mallet technique. Once the carpet is back in, you should not be able to tell that the bars are not a factory installed part.

 

[72bluNblu]

I made my own as well, 1.5x3x.120" tubing. 2x3 requires floor mods. You don't need to go inside the rear frame rail, you can overlap the outside with the 3" wide tubing. I made some pretty large landing plates to cover the existing frame and crossmember.

I also just finished installing a set of US Cartool connectors on my '71 Dart. There's no way I would ever do that again without a rotisserie. None. A colossal pain in the butt. Strip the entire interior, strip the area where the connectors will contact the underside of the floor which meant scraping undercoating and wire wheeling everything. Then spend a day just fitting the subframe connectors to the floor so that all the weld gaps were manageable, grinding, hammering, jacking the connectors into place to check fits as jbc426 described. Then another couple of days of welding underneath the car, slag falling on you, crawling around on the floor, etc. I don't have the exact amount of time because I was doing torque boxes and torsion bar crossmember gussets too, but I probably spent a good 8 hours just on the connectors. I fully welded mine to the floor, which means a TON of welding. But IMO if you're going to bother fitting them to the floor to begin with they should be fully welded, stitch welded will not be as strong and then you have to seal them. I only left a couple places "open" from being welded to the floor, specifically I ground a notch into them to pass the fuel and brake line through. I still have to drill the holes for my parking brake cable.

The only benefit I see to the floor formed connectors is they look more original, no big piece of tubing under the car. But the whole process probably took me 4 or 5x longer than making my own out of the 1.5x3" tubing. There's a TON more prep that has to be done because of the amount of welding. And then you have to re-route and reform the fuel and brake lines and snake the parking brake cable through the connector too. And I really don't see them making the chassis any significant amount stronger than a set of tubular connectors that have decent sized landing plates. I don't get any noticeable chassis flex from my Duster, which has the connectors pictured above. I'm sure the weld to floor kind are plenty strong, but I don't see there being enough of a difference to justify the amount of work and added expense unless you really don't want the tubing under your car. I'm trying to keep my Dart more original looking, it has the numbers matching engine etc and being a GT is somewhat rare (not really more valuable though). That's why I went with the US Cartool connectors, that and I hadn't done them before. And that was the last time I'll do them unless I'm installing them on a rotisserie, right side up on a fully stripped and blasted chassis.

 

[MRGTX]

You guys make cutting them out of square tubing sound like a breeze. Yeah. They're pretty simple but this presumably requires a level of precision and a set of tools that some of us lack ;)

What's the verdict on the middle ground; welding in the bolt-in style connectors?

 

['Cuda_ragtop]

Started out looking at just sub frame connectors and ended up with:
US Car Tool Full radiator core support for 26" Radiator, SF connectors, F/R torque boxes, shock tower reinforcements and inner fender braces.
I test fit, cut, test fit, ground, test fit, ground some more... then paid shop rate to have them welded in at my body shop.
Car was on my rotisserie and upside down for all the test fitting.
On the rotisserie at the shop too but on tall jack stands at the suspension mounting locations for welding them in.
Should make it stiff! Look like they belong there.

 

[72bluNblu]

You guys make cutting them out of square tubing sound like a breeze. Yeah. They're pretty simple but this presumably requires a level of precision and a set of tools that some of us lack ;)

What's the verdict on the middle ground; welding in the bolt-in style connectors?

Cutting them out of square tubing is pretty easy. The only tools I used to do it was a grinder, a chop saw and my MIG welder. And you don't need the chop saw, a grinder with a cut off wheel will suffice. The level of precision isn't bad either, I mean, if everything ends up within a 1/4" you're fine.

Started out looking at just sub frame connectors and ended up with:
US Car Tool Full radiator core support for 26" Radiator, SF connectors, F/R torque boxes, shock tower reinforcements and inner fender braces.
I test fit, cut, test fit, ground, test fit, ground some more... then paid shop rate to have them welded in at my body shop.
Car was on my rotisserie and upside down for all the test fitting.
On the rotisserie at the shop too but on tall jack stands at the suspension mounting locations for welding them in.
Should make it stiff! Look like they belong there.

Nice! Yes I definitely agree that the US Cartool stuff looks more at home than using tubing. And I have no doubt that it'll stiffen the chassis. I ended up doing almost all the same stuff, I have the lower core support, subframe connectors, torque boxes and the shock tower/inner fender braces. So far everything is in except the shock tower/inner fender braces, but I've done that sort of thing before too and not being under the car they'll be a lot easier than the subframe connectors were. In the end I think the Dart will end up being almost as stiff as the Duster, I think the j-bars and tubular lower core support on the Duster will end up being a little stiffer than the US cartool inner fender braces and lower core support. Mostly the J-bars because of the way they tie the frame rails into the firewall and shock towers compared to the inner fender braces. But the Duster doesn't even begin to look stock. Not even stock-ish like I'm hoping for the Dart. And the J-bars require a battery relocation too, where the inner fender braces do not. Plus I think the US Cartool stuff has a bit more of a reputation, ie, for resale if I say the car has a level II chassis stiffening kit from US Cartool I think that will carry a bit more respect than if I say I did a bunch of homemade chassis stiffening, even if the end result might be a stiffer chassis.

The rotisserie is the difference maker though. Between that and the media blasting you pretty much eliminate the biggest hassles of installing the weld to floor connectors. Doing it on a car that's just on stands and hasn't been fully media blasted is just a ton of not fun work.

 

[whitepunkonnitro]

Bolt in and floor fitted frame connectors are apples and oranges.
Bolt in are intended to spread the push from the rear axle forward, taking some of the load off the rocker panels.
If you are drag racing a moderately high power car with slicks and otherwise stock unibody, they are fine as is. Welding them in won't stiffen the car one iota.
Floor fitted rails are to stiffen the entire unibody an help keep it from twisting.
Very high horsepower cars that don't have a cage tying everything together, and road race type cars benefit from that setup.

 

[spl440]

Had rusted front floor pans, so at the same time of the forward floor repair, cut the rear pan and slipped in 2x3 tubing 3 inches into the rear frame and a couple of inches into the forward frame, welded entire length. I do not sit in the back so do not notice the small hump in the rear carpet! drilled hole in tubing for parking brake cable and gave me a secure place to attach rear battery cable. noticeable improvement in handling.

 

[67autocross]

Here is a few pictures of a out of the box subframe connector install.. the connectors run inside the the rear stub back to the spring boxes. At the front they line up with the edge of the torsion bar socket and are welded to the side to give the socket extra support.