Sub-Frame Connectors Better than other?

[Blown70]

Ok, I did do a search (troy).  Does anyone have a preference in Sub-Frame connectors.  US car Tool.  XV motor sports. OTHER?

Thanks for any info.

Tom

[Ghoste]

I don't own a set (yet), but I have looked at a few and personally, I like the US Car Tool ones best.  I just like the idea of being made for the car and having met John Paseman (the owner and a 66 Charger freak as well) a number of times, I came away impressed.

[moparguy01]

2x3 rectangular tubing. thats what i've used in a 2nd gen charger and its cheaper.

[The70RT]

I got the MoPar ones # 1-P4286869. The car tool ones look better and look more factory. Any way you go the purist will  be Mine is just a U code R/T so...........

[Mike DC]

I'm a fan of welding them into place and staying relatively small with the tube.  Just get whatever decent SCs you like that don't cut the flooring to shreds, and get them mounted well.

Something like 2x2 or 2x3 steel is certainly "good" for SCs, but welding gigantic I-beams into the area isn't necessarily "better."   You just need enough added frame in center the area to make it not be the weakest link in the whole chassis any longer.  Once you've even just got some 2x2 square tubing or something in the area, the biggest flexing point in the chassis is probably gonna be moved to somewhere else.  (Like the torque boxes if you don't have them.)   

 

[Big Sugar]

I'm a fan of welding them into place and staying relatively small with the tube.  Just get whatever decent SCs you like that don't cut the flooring to shreds, and get them mounted well.

Something like 2x2 or 2x3 steel is certainly "good" for SCs, but welding gigantic I-beams into the area isn't necessarily "better."   You just need enough added frame in center the area to make it not be the weakest link in the whole chassis any longer.  Once you've even just got some 2x2 square tubing or something in the area, the biggest flexing point in the chassis is probably gonna be moved to somewhere else.  (Like the torque boxes if you don't have them.)   

 

I agree.

The Us Cartool units are nice if your in the middle of a full resto , But there is a easier way just going with the tubing. Auto Rust technologies
have a good description as well as photo's on a typical Mopar installation .
That's the route I would choose.


Ron

[suntech]

I think there is no question about what style gives the best improved rigidity. That is the style that XV and US Car Tool is the ones that gives best improvement, beeing welded against the floor. That boxes up the construction a hell of a lot better than anything else!
The downside with them is that all that welding requires stripping carpets and stuff inside, so i guess it depends on where you are in the resto prosess, what engine that goes in there, and if it is going to see strip action on slick tires.
On the XV dvd, right from the beginning, you can see a Cuda launch, on the strip. There you can actually see that the body warps, and door openings are getting 3 times as wide in top, so there was NOT strong enaugh connectors.
Rolf

[Blown70]

Ok, that helps but I had not planned torque boxes,  I see that maybe something I should plan on while under the car too?

Thanks again for all the replies.

Ohhh the car will be stripped too, so welding to the floor would not be a problem and the car is an XP not XS, so being a non-R/T car I am not too concerned with the value...

Thanks again.

Tom

[BrianShaughnessy]

Ok, that helps but I had not planned torque boxes,  I see that maybe something I should plan on while under the car too?

Thanks again for all the replies.

Ohhh the car will be stripped too, so welding to the floor would not be a problem and the car is an XP not XS, so being a non-R/T car I am not too concerned with the value...

Thanks again.

Tom

XP / XS - don't matter... put them on.    Put on the torque boxes too.    I've had them on for years.   

If I had a trailer queen XX,  well maybe I'd think twice before welding them on.

[suntech]

When you are in the stage you are, i think your choice is simple then!!!! Weld in sub frames, like XV or Us Car Tool, and a set of torque boxes, and you´re all set
Remember to drill drain holes in the subframes, to allow anti rust treatment. 
Rolf

[firefighter3931]

I think there is no question about what style gives the best improved rigidity. That is the style that XV and US Car Tool is the ones that gives best improvement, beeing welded against the floor. That boxes up the construction a hell of a lot better than anything else!

Rolf

I'm not convinced that a 3 sided connector (XV/US Cartool) is stronger than a fully boxed thickwall tube like the MP setup. The floorpans are thinner than the solid connector and therefore weaker.

From an appearance standpoint the contoured connectors "look" nicer but are they really better ? 



Ron

[Ghoste]

If they're thinner, couldn't the argument be made that they need a little help that much more?  It is a uni-body so the entire vehicle is part of the load carrying structure, correct?  Kind of an every little bit helps thing?
That's a lot of question marks huh?

[suntech]

Ron
I am pretty damn sure they are better, simply because the way this design box up the construction, and that itself makes it much better than an "added on" tube, just fixed in each end.
I am working on QC dep in a big company, mostly testing cranes, to put on offshore oilrigs, and the ONLY downside with a boxed construction, is the side surface area, for the wind to grab on to, operating them in bad weather. In all other areas it has a superior weight to strength ratio, so i will still put my  on the boxed ones, since the side surface area is no issue here, but this is just my opinion

Rolf

[The70RT]

I think there is no question about what style gives the best improved rigidity. That is the style that XV and US Car Tool is the ones that gives best improvement, beeing welded against the floor. That boxes up the construction a hell of a lot better than anything else!

Rolf

I'm not convinced that a 3 sided connector (XV/US Cartool) is stronger than a fully boxed thickwall tube like the MP setup. The floorpans are thinner than the solid connector and therefore weaker.

From an appearance standpoint the contoured connectors "look" nicer but are they really better ? 



Ron

I was wondering the same too Ron. Nobody else spoke up so I thought why bring it up? The XV/US Cartool look more factory but a real Mopar person knows anyway. The XV/US Cartool ones take more time to install and would cost more to have them installed if you had someplace do them for you.

[Troy]

The XV/US Car Tool connectors are only three sided until you weld them in. They are just like the factory frame rails so I don't think the thinner metal on the floor would significantly weaken anything. I never realized how much strength you could get out of something once it's tied together until I built a steel carport/building. That metal is thin and the whole thing seems rickety but after you stick a few hundred bolts in it to tie all the parts together it's rock solid. I have rectangle tubes cut for mine but I doubt that I will use them since the contoured ones blend in so much better. Torque boxes tie the rockers (which are as thin as the floors but without stiffeners) to the frame rails so a combination of both should really stiffen things up - no matter which subframe connectors are used. If you look at most road racing cars they'll also have an 'X' brace under the center of the car and gusseting at all the frame intersections to keep the chassis square.

Troy

[piwo440]

I lurk around here a lot, but don't post much,  I am usually on the 66-67 Charger forum.    But I thought I would put in my  anyway!

I just installed USCartool connectors in my 66 Charger, excellent pieces!  I talked to John on the phone before buying them and he told me outright that they would need a little trimming to fit perfect, and they did.... not much though.  I love the idea of having them look factory, even though as said before, anyone would know they don't belong there.  As far as the ease of installation,  yes... you have to strip out your carpet seats, etc...  but why would anyone want to sacrifice and take short cuts on something like this?  For all the time and money we put into our cars, do it right, and do it the way you want to....  not just "do it the easiest way". 

I have not yet been able to test them, car is still "under construction", but with my 20+ years experience with unibody vehicles, (work in collision shop)... I believe these are the better set up.....  I think it was Troy that was talking about how strong something was when all tied together,   and he is correct,  you can take any individual piece from a unibody vehicle and it is flimsy as hell....  once you start welding the structure together,  it gets very strong. 

There ya go.....  for what it's worth....   my 

Ron
66 383/727
ZZ1 P4W WW

[firefighter3931]

Ron
I am pretty damn sure they are better, simply because the way this design box up the construction, and that itself makes it much better than an "added on" tube, just fixed in each end.
I am working on QC dep in a big company, mostly testing cranes, to put on offshore oilrigs, and the ONLY downside with a boxed construction, is the side surface area, for the wind to grab on to, operating them in bad weather. In all other areas it has a superior weight to strength ratio, so i will still put my  on the boxed ones, since the side surface area is no issue here, but this is just my opinion

Rolf

Rolf, i understand what you are saying but you have to consider the wall thickness of the tubes to make a valid comparison. The square boxed .125 MP connector will be stronger than the stamped tin floorpan...wouldn't you agree. 

Also when you weld sheetmetal the original structural integrity is compromised somewhat. 

Having been around many, many racecars i can tell you the frame connector of choice is allways a thick wall boxed tube that does not use the floorpan as a structural member. 


The US cartool/XV connectors are nice looking and i'm sure are a huge improvement over an untied front/rear subframe but they would not be my first choice for a high HP street/strip dual purpose car.


Would i use them on a hot streetcar/cruiser type build that sees the occasional track pass....absolutely.




Ron

[suntech]

Hi Ron
For a street/ strip (stoplight to stoplight) application i buy some of your points, but i still mean that in overall the welded ones will perform better, spesially in warp/ twist.
This because the connectors help to hold the floor in place, hense help the warping strength, simply by holding the floorpans where they are supposed to be. The hump for the driveshaft does a similar job, with the floor in the car (floppy like hell as a loose piece, but helps stiffness when fitted in)
The 3 sides of the connector will make it even even stiffer. All 3 sides help the same way as a bolted on connector, and the bottom side and top (the floor) helps warp. this effect is much stronger when fully fixed against the floor, since it then help the existing parts to be stiffer. ( a cardboard box is pretty darn rigid, if properly taped together)
I understand that people question this, specially with the thin walls etc, but it is really amazing how far down on material thickness you can go, when you "lock" the construction in a correct way.
XV did a lot of work in the 4 post test stand , calculating how many pounds of force , pr degree of twist etc. then they added different stuff to the car, to make it stiffer, and then tested again. I would assume, with the money and time they have putted in to their program, they thought carefully trough what they did.
But again, just my opinion!! That is the great thing with this forum........we can release our brainfarts
Rolf

[BrianShaughnessy]

I don't want to knock anybody putting on connectors... because I believe that they are one of the key things that should be done to any old unibody musclecar to help stiffen it up.   I don't care what brand somebody decides to use as long as they are used.   Old cars twist, flex  and creak and it's unnecessary...  I would put them on the list of upgrades that should be done if and when possible along with front disk brakes and electronic ignition.   If the basic unibody structure was compromised by collision or rust and or rust/collsion repair...  it just seems logical given a choice.

But I will say in defense of the old MP's and other  box tube designs...    you can use them as jacking points - I probably wouldnt' do that with the uscar or xv designs.    I know I have.

Isn't it great that now's there's a range of choices of what type to use?     5 or 6 years ago there was MP's... and auto rust technicians was just coming out with theirs.

[Steve P.]

I gotta say that all sides of this are relative. My .02 :

1) absolutely these cars need to be stiffened up for every reason.

2) Both the square tube and 3-sided designs will work well. Especially if done right. Just bolting them in is a help, but welding them in is really the only good way to go.

3) The US Cartool connectors look great and from all my experience working with steel in the nuclear field I can tell you that Troy's point of multiple connections is exactly right. Also as long as they are MIG welded in the floorboards should not be made brittle from the welding.

4) The square tube is thicker than the factory sheet metal and the framing from Ma Mopar. This being said, the week point of adding the tubing is at each end where it is welded to the framing. I personally don't think the aftermarket uses enough plate at each end of the box tubes. I believe the forward end should have a channeled U-channel that can be welded on both the back and the front of the cross brace. Without doing this the cross brace is now a weaker point than the rest. At the back they do form a socket of sorts and it is, I feel, much better. Just welding the through holes and bolts is more of just a bandaid. They need to be completely welded.

5) What I like better is 2x3 rectangular tubing. I have seen it laid on the flat and I think it helps more this way to keep the body from racking. Again I much prefer this done with a C channel at the front..

6) Another way I like is more for the drag crowd than the street crowd. This is using 2x3 tubing in the vertical position, only cutting through the floor boards and channeling them in. This lets you weld on both sides and gives a much better land area for the ROLL BAR.   

7) Along with welding in the ties, the floors only have spot welds from the factory. Full welding the joints will also help to keep the body from racking.


Any ties are better than no ties. More welds are better than a few tacks and bolting in your ties is only slightly better than no ties.

This is just MHO.... 

did I mention that my last 65' had 1/4 wall 2x2" tubing with lots of extra plating??  That wasn't going anywhere... 

[Troy]

Another thought if you're really looking for the strongest approach yet still want it to look like factory...

I think it was Daytonalo (shhhh, don't tell him or you'll feed his ego) that put a square tube inside the US Car Tool connectors to make them stronger but keeping the smooth look. From my little understanding of metal I do agree with Ron that the square tube is probably strongest but it's only welded on each end. It doesn't matter how thick the tube itself is when you're welding it to thinner metal as the joint becomes the weak point. Welding them down the entire length distributes the load. It'd be cool to actually measure the difference but not many people have the equipment or resources to do that. Even XV incorporates an entire stiffening system instead of just the connectors so that all weak points are covered and compliment each other. For what it's worth, I paid $20 for enough tube to make three cars worth of connectors (and got them cut for free) so there's another advantage to the basic approach.

Troy

[Mike DC]

 
All this is good stuff.  But after a certain point the rollcage begins to be the heavy-lifter in terms of chassis rigidity.  If you've got decent SCs & torque boxes and you're still worried about it, then IMO it's time to start putting the effort into a more extensive cage. 

The XV braces at the front rad support and the shock towers are certainly good too, but XV was really thinking about uncaged cars on road courses more than dragstrip work specifically.  (For that matter, their top level front suspension setup involves tossing the torsion bars and mounting the vehicle wieght onto the front shock towers with coilovers.  Little wonder that they're in favor of adding some extra shock tower bracing.)




Dragstrip launches mostly tend to distort the rear 2/3 of the unibody behind the tranny crossmember.  Those harsh wheels-up launches are the equivalent of basically grabbing the chassis by the rear suspension mounting points, and then trying to hold the front end tilted up into the air that way.  And the right side-unloading of a solid rear axle is having a similar effect on the stresses from side to side.

The front 1/3 of a drag car doesn't usually get affected a whole lot unless you lift off the throttle during a wheelie and crash the front end down hard on a set of floppy front springs.  (The desert race truck crowd has made MAJOR leaps & bounds on improving bumpstop tech in the last decade.  Sooner or later that stuff will probably start showing up in the front ends of dedicated drag cars as a safety precaution.  It would really save their floppy-sprung front ends & oil pans on hard drops.)

           

[suntech]

This is also what i mean!
20 years ago, nobody was thinking about a muscle car as a road "racer" !!
It was all about dragstrip performance back then, and subframes was buildt to hold up agains the forces applyed to the chassis on brutal big hp slick launches.
In a pro touring car you want other qualities from the chassis. Body warp, and front end rigidity is important, to get the car to handle on a racetrack, or curvy roads.
I think this is one of the reasons that we have different ideas of how to do stuff like this. A clash between old habits, and new ideas and userpattern.
Rolf

[Blown70]

Sounds like a good discussion here.  I will be putting a roll cage in the car too, and thus have more structure to make the car rigid.  However not sure how much of a cage at this point.

I already planned on plating a few parts of the existing frame, and the care will be completely stripped to do so..... no worries there.

THANKS FOR EVRYONES IMPUT...

Tom

[firefighter3931]

Sounds like a good discussion here.  I will be putting a roll cage in the car too, and thus have more structure to make the car rigid.  However not sure how much of a cage at this point.

I already planned on plating a few parts of the existing frame, and the care will be completely stripped to do so..... no worries there.

THANKS FOR EVRYONES IMPUT...

Tom

Tom, the cage is an excellent idea !  Mine has an 8pt bar in it and it made the chassis so much tighter that it's not even funny. With a Blown motor in your future this is a no-brainer. 



Ron