Sub-frame connectors... Please build them correctly!

-
I just toss a few Viagra pills I stole from my neighbor in the tank before a drive. He drives a Prius so I know he won't mind.

Things you don't discuss on the forums: Religion, politics, oil, spark plugs, fuel grade, and now sub frame connectors.
 
dano said:
I just toss a few Viagra pills I stole from my neighbor in the tank before a drive. He drives a Prius so I know he won't mind.

Things you don't discuss on the forums: Religion, politics, oil, spark plugs, fuel grade, and now sub frame connectors.
Click to expand...

Some people just get way too emotional over subjects that require a rational state of mind.

72bluNblu said:
If you want your connectors to look somewhat factory, and are tearing the car completely down to the chassis and putting it on a rotisserie I don't think they're a bad way to go at all.
Click to expand...

I definitely wouldn't install frame connectors while a car is on the rotisserie. In my opinion you want it resting on a level surface and fully supported or I think you could "lock it in" to a slightly twisted position. I could be wrong but I've seen how door gaps change while a car is rotated around on one.
 
451Cuda said:
I definitely wouldn't install frame connectors while a car is on the rotisserie. In my opinion you want it resting on a level surface and fully supported or I think you could "lock it in" to a slightly twisted position. I could be wrong but I've seen how door gaps change while a car is rotated around on one.
Click to expand...

I've never done it myself. But I've followed several builds that did it that way here at FABO and at a few other forums, and all of them went back together without any significant body fit issues. Nothing that you don't run into on these cars normally if you've completely disassembled them. I have yet to see a post anywhere about someone installing frame connectors and then not being able to close the doors, adjust the gaps, etc. Not saying it can't be done, but I think it's harder to screw up than people think.

Personally, I install mine with weight on the suspension and I check all the body gaps before I start to make sure everything is where I want it before I start welding. But that's probaby overkill.
 
Installed mine while car was on the lift, all the lift arms were on the front and rear subframe to support it, the suspension is just hanging there, of course we welded them in with the doors on too, everything lined back up with no issues. Welding to the floor deff adds strength, as mentioned before the floor pans adds rigidity by themselves, welding the connectors to the sub frame and floor creates a box replicating a frame. I can jack my car up in the middle or at the front or rear of the subframe connectors and still open and close the door like its sitting on the ground.
 
71DodgeDemon340 said:
Oops im sorry my properly fitted fully welded sub frame connectors for my street car are wrong
:eek:ops:

Before everyone says this is wrong. mine is right blah blah you should take in consideration for the type of project being done, these weld in connectors are absolutely 100% practical for most of us who have street cars, I noticed a big improvement of launch and handling. To say that these are incorrect is ridiculous. However the prep and weld procedure is crucial. what works for some may not work for others and what works for others may not work for everyone, all boils down to build. And welding the front and rear of the connectors to the subframes and floor is completing a box thus in turn making it a full frame. If I remember correctly i believe the connectors i got were 3/16" thick, plenty strong
Click to expand...

sorry you took my sarcastic response as golden.

i have always had a saying that my wife uses often. "something is something and thats better than nothing at all".

most think of connectors of long ways strengthing. most dont realize they are for twisting of the car like wringing out a wet wash cloth in your hands type of twisting. just adding the strait bars only do so much. the support from the center to the edge is a vast improvement but the need for this all. that truly goes along with goals and wants of the chassis itself and the user. for me was no flex for drag racing. for others its road racing around corners strength. truly if you can get cross connectors to go along both directions of the floor and diagonally across that area. that is the best idea but not usually worth the hassle to 99%.
 
Well thats my bad, hard to tell someone is being sarcastic online lol i just assumed because its not uncommon on here. I understand your point, weld in subframe connectors alone are fine for street but like you mentioned in drag racing 0 flex is ideal to get the most out of your suspension. The subframe connectors improve handling and launch, my main goal on mine was to help the handling and launch on the street as much as i could for a reasonable price. so I installed the weld in subframe connectors, lower control arm stiffeners and front sway bar. however if i were doing autocross id look into more stiffening as i would in drag racing
 
Looks like the answer is personal preference without any
data to back things up.
Suits me, I was hoping somebody out of 40K members had
found or did some testing and would be able to share.
 
longarm said:
Looks like the answer is personal preference without any
data to back things up.
Suits me, I was hoping somebody out of 40K members had
found or did some testing and would be able to share.
Click to expand...

well there is decades of data to use honestly. the future is now and still changing as days go by. remember top fuel used to be a lap belt and single halo style cage on dragsters. crazy in todays mindset but back then it wasnt a priority or fear. times and people change focus or expand that focus.
 
I installed mine upside down on a rotisserie on my Dart. Hope I can get doors to fit after I weld the roll cage in.
I think I rotated it right side up and supported by jack stands before connecting front to rear. Can't remember, we will see.
Anything is better than nothing. Your choice of what you want and can afford. My Duster flexes like mad on the track without any.
 
Jo Diesel said:
I installed mine upside down on a rotisserie on my Dart. Hope I can get doors to fit after I weld the roll cage in.
I think I rotated it right side up and supported by jack stands before connecting front to rear. Can't remember, we will see.
Anything is better than nothing. Your choice of what you want and can afford. My Duster flexes like mad on the track without any.
Click to expand...

I remember the first time we got the hemi to hook up w/ 16" tires on it, got back to the pits, the door wouldn`t open right. then when I tried to close it , it just bounced back at me ! we put home made cheap tube type connectors on it, w/ a cheap roll bar , it helped but didn`t completely stop it. that`s why I went thru the floor and inside the rear frame rails on the fish, went w/ full 1/8" thick 2 " square tubing too.
 
longarm said:
Couple of articles.

http://victorylibrary.com/mopar/frame-c.htm

http://www.deadnutson.com/building_a_mopar.html
Click to expand...

The first article is interesting, but it's really no better than the discussion here. Who wrote it? What qualifications does that person have? Data?

Yes, taller connectors resist twist better. Pushing them out to the rockers helps as well, as being wider on the chassis will also help to resist twisting. But how many people are going to cut their doors down to increase the height of the rocker and make the step over height 5 or 6" taller? And, is it necessary anyway? If you need that kind of chassis stiffness, you are probably in need of a full cage. Not to mention that a lot of racing rulebooks don't allow for those kinds of modifications to the rockers. And, because of the extensive modification to the rockers, the execution of the installation would be very important. If that installation was done poorly you could actually weaken the structure of the car. With the standard tubular connectors or the weld to floor connectors poor execution just limits your improvement, you would have to work pretty hard to compromise the structural integrity of the chassis. If you start by cutting apart your rocker boxes, you have a lot of ground to cover. The end result could definitely be stronger, but if it's done incorrectly it could also be catastrophic. The application seems very limited to me. If you have a full chassis shop to make those kinds of modifications, you should just make a full cage. If you're doing it at home, you're biting off a REALLY big chunk.

You can use basic engineering principles to argue for any of the types of subframe connectors discussed so far. But without an actual test, and without actual data, it's really just speculation. Sometimes informed speculation, sometimes not. And ultimately there is a limit to how stiff any connector can make the chassis, because they're only one component of the chassis and they're still connected to the rest of the chassis. At some point you have to go to a cage. Which is why it would be interesting to see actual torsion tests. My own speculation is that the type of connector isn't as important as people make it out to be, because there's a limit to what any type of connector can add to the chassis. But that's just my own personal speculation, and I absolutely could be wrong.
 
all this discussion is interesting no doubt, but probably 98% of the people here build simply street driven drivers, with MAYBE a some built updated engine!? so i'm pretty darn sure simple homemade tubing connection the sub frames will do anything we wish!???

I have had stock 440 4 speed B Bodies, that sat twisted and catty wompuss from twisting torque. I bet a simple subframe connector would have prevented such.
 
I found this post/thread when searching for subframe connector types. From the OP, I disagree with that assessment. He tried to back off of his original assertion (that connectors not tied to floor were/are worthless or next to worthless) but in any case, I do not agree. I am not an automotive engineer (but I have one on the family) but the parallel support argument does not ring true in this case. The reason that the subframe connectors DO add significant stiffening even without welding to the floor is that indeed they are creating a box effect. The one side of the "box" being the connector with the other side being floorpan (with all the inter-related connections of the floorpan to the subframe, rocker, crossmembers, etc). Without a doubt, some connection to the floorpan is better for rigidity (the more connection the better...as is gusseting/torque boxes/connection to rocker) but the idea that these connectors without floor connection is "next to worthless" is an idea that I do not support.
 
Agree, plus full frame cars are not welded to the floor. Yes, they may be thicker, but are only bolted in about 6 spots per side. So welding from one end to the other, ties the two welded subframes together.... better than nothing :)
 
jrlegacy23 said:
Agree, plus full frame cars are not welded to the floor. Yes, they may be thicker, but are only bolted in about 6 spots per side. So welding from one end to the other, ties the two welded subframes together.... better than nothing :)
Click to expand...
Good point about full frame cars not welded to floor/body. If you work with some full frame vehicles... you may notice that both the frame and the body become more rigid when they are joined, albeit bolted, together...and that is even though they are bolted together through a stiff but flexible rubber bushing ("hockey puck") as well.
 
I was speaking with a near neighbor down my street - he has a bit of a shop built in his backyard for his part-time after work job. He welded up my K-member for me and I then asked him about installing some welding in SFC. Mentioning that I would want the weight off the car on all four wheels he said what he would do is get under the initially and tack them in place, then put it on a lift (not the drive on type) and then finish the welds in a more convenient position.

Is this a reasonable approach?
 
Geo4K said:
I was speaking with a near neighbor down my street - he has a bit of a shop built in his backyard for his part-time after work job. He welded up my K-member for me and I then asked him about installing some welding in SFC. Mentioning that I would want the weight off the car on all four wheels he said what he would do is get under the initially and tack them in place, then put it on a lift (not the drive on type) and then finish the welds in a more convenient position.

Is this a reasonable approach?
Click to expand...

Sure, if nothing moves much when it's lifted and/or his lift arms are level with each other and placed in spots on the car that are also.
When we did mine all we did was put it on jack stands and use a laser level to check the body for flat and welded the connectors in.
It's pretty difficult to try to get a person that volunteered to help to do it the way you want it done though. :D
 
I have done them on the rotisserie and I would not worry at all about the car twisting unless it's a rusty pos.
At the back I would weld them into the leaf spring mount and at the front make a small triangular plate so that about 6 inches of contact with the factory cross member.
If you are installing a roll bar bring the main hop through the floor and weld it to the top of the connector.

image.jpeg
 
You must log in or register to reply here.
-

Back
Top