Subframe connectors

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project74

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I'm curious as to what's better, weld on or bolt on subframe connectors. Are there any specific advantages to one over the other? The dart will eventually be getting a V8 transplant, probably small block, around 300-350 hp. Many thanks for any posted replys.
 
Personally, I feel that welding 'em in is easier and better to do. Drilling for the bolts, it's very difficult to get the holes so that the bolts fit in with no play at all. Even with the bolts ratcheted down tight, there is likely to be some movement because of the tremendous rotational torque applied to those areas. Plus, in my case, I used the subframe connectors as an anchoring point to attatch the roll cage behind the front seats.
 
I#am in the middle of the weld in process. Its not that easy as it should (for me), 'cause I only can lift the car 10" of the wheels...

I make it like the guys from www.bigblockdart.com made it.

The driverside one is completed today.

Michael

Uups, weld-ins are a lot stiffer I'd say...
 
the bigblock dart way is good, but this is the best way to do it IMO. slot the floor and allow the connectors to come through the floor and weld the floor to them too as well as to the front and rear subframes. this is just commenly available 2"x3" x .125" thick rectangular tubing. these pics are from a 71 charger i just recently did. if i remember right, on an a-body, they are not as obtrusive in the rear foot well area as here on this b-body. also, the 2x3 on end just happens to fit nicely inside the stock rear frame rails making a very strong overlap joint---espesially for cars with springs moved in.

--chad

subframe1.JPG


subframe2.JPG


subframe1.JPG


subframe2.JPG
 
Yeah, the B bodies require some more surgery than the A bodies. On the A's they tie together without cutting into the floorboards like the B & E's.

That's why A bodies rule.... well, one of the reasons.
 
My Mopar Performance connectors are welded in. The hit the floor though so they arent sitting right. Im going to need to cut them out and slot the floor pan to get them in right and reweld them.
 
actually john, even on an a-body, they do go through the floor when the tubing is stood on end like in the pics i posted. you only see about an inch of it though in the rear footwell, as opposed to the whole 3" that you see in that b-body. however, like you pointed out, you can turn the tubing on its side and not cut the floor--which some owners prefer. to me, most cars will never get returned to stock, so cut away what you will.
 
Turbodart,
Do you have any more pics or suggestions for the connectors on an A body? I just happened to have some 2x3x.125 tubing at home. (It was for the Camaro, but the Dart needs it more.) Did you make any templates for the installation?

Thanks for any help.
Ken
 
Is .125" thick tubing really necessary? No other chassis metal is that thick, just seems to like a lot of extra weight that will add little torsional stiffness. Also, why 2x3 if you aren't going to have the 3" dimension vertical?

I am planning connectors for my Barracuda shortly and I was going to uses 2x2 tubing with a whatever is availblke in the .060" thick range.
 
dgc333 said:
Is .125" thick tubing really necessary? No other chassis metal is that thick, just seems to like a lot of extra weight that will add little torsional stiffness. Also, why 2x3 if you aren't going to have the 3" dimension vertical?

I am planning connectors for my Barracuda shortly and I was going to uses 2x2 tubing with a whatever is availblke in the .060" thick range.
Click to expand...

Dave,
I tend to believe you that the .125 is too thick, especially when you look at it. However, the other piece of this puzzle is the roll bar/cage. Most racing classes required wall thicknesses for mild steel to be .120 depending on the diameter and weight of the vehicle. If you are going to tie your cage into the subframe connectors, they might as well be as thick as the cage tubing. The extra weight isn't too much of a concern because it's located so low in the car. The added stiffness, and resulting better launch, should offset any weight penalty.

Ken
 
Ken,
The roll cage consideration certainly makes sense. But, when you talk about stiffness (i.e., the ability to resist twisting and bending) of a tube the wall thickness has a minimal impact compared to changes in diameter.

Wall thickness becomes imoprtant when the need to resist impact forces are important. Bicycle tubing is a good example, some of the real high end bikes are extremely stiff for efficient pedaling but the tubing wall thickness is so thin that you can dent it by squeezing it with your fingers. Once it's dented it's looses it stiffness dramtically. A roll cage by definition is subjected to impact forces and that's why the wall thickness is so high.
 
Dave,
You're right about the thickness not contributing too much to stiffness, but it does help depending on what direction the tube is bending. Also, what I meant about the wall thickness of the tubing, is that it's a lot easier to make a good weld when the two pieces are the same thickness. For the expert welders that is not as important. While I am a decent welder, I am no expert.

Take a look at our website for some pics of the installation. I am really happy how it came out. I am going to ask our man Justin to post some more pics of the welds in the rear frame area. We were able to weld in many places, distributing the load over a large area. The roll bar installation on coming along well. Pics for that coming soon. All in all, this car is going to be a lot stiffer. Hopefully, that translates into consistent launches.

http://www.oakland.edu/org/pdmc/dart.htm

Thanks
Ken
 
I think there's a company working on making connectors that conform to the floor pan of the car. You weld them to the floor and the sub frames. So there's no intrusion in the foot well. I think the name is uscartool.com They are working on e body connects I think A bodies are next.
 
Hi all, new guy here. I've been working a project to restore a '74 Duster. It has a '71 340 4sp transplanted into it and just needs alot of fixup-type work along with some small structural/body rust repair, new interior, etc. But it sure runs strong!

So after I tore out the interior to rebuild the trans hump (amatueur attempt - yuk!) and found some rust holes, I decided to go ahead and do the SFC thing as long as the floor was all exposed. I think I found or developed a good way to get the 2x3 tubing in without much floor surgery needed.

I fabbed up the SFC with a front plate to butt the crossmember, as normal. I measured it out to extend about 8" back over the rear frame with an angled cut up to where the floor meets the rear frame. Now here's the trick part.

As many have noted, it will not go all way up before hitting the floor, maybe 3/8" to a half inch shy of seating down firmly against the bottom of the rear frame. So I made two cuts down the length of the floor ribs where it hits. Didn't cut anything out, just split the ribs. The positioned it in place in the rear with the front hanging down a few inches on a jack. I made one good weld across the bottom at the very rear, where it needs to be. Then I raised the front into position with the jack. I took a few good whacks with a sledge to get it up. The splits in the floor allowed enough flex for the SFC to go into position with just a bit of a bulge into the floor. Dropped a few spot welds into the SFC through the floor, welded it back up and completed the main welds all around the front and rear SFC butts.

Seemed to work pretty well, and I think maybe even tightens up the overall body interconnect by the tension of forcing it into the floor. Questions/comments?
 
furrystump said:
I think there's a company working on making connectors that conform to the floor pan of the car. You weld them to the floor and the sub frames. So there's no intrusion in the foot well. I think the name is uscartool.com They are working on e body connects I think A bodies are next.
Click to expand...

Heres a link

http://www.uscartool.com/Eframeconn/index.html
 
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