Moparts
Sub frame connectors
Posted By: Dr Dave
Sub frame connectors - 12/23/14 08:43 PM
I know weld in is best but the underside of my Cuda has already been painted and assembled. I have the cowl and rad support bracing welded in. Running 528" Hemi with Alter K and Tremec TKO 600, 17" and 18" wheels with good rubber. This will be mostly street driven but want to maximize the package. Currently with the car on my lift the doors are hard to open and close due to body flex so wanting to fix this the best I can. What do you guys recommend for bolt in / minimal weld in that will help without losing ground clearance? Thanks!
Posted By: TC@HP2
Re: Sub frame connectors - 12/23/14 10:13 PM
Hotchkis, Competition Engineering, Mopar Performance, Moroso are all either basic bolt in kits or minimal welding required packages.
Since your car is assembled, it is probably best to install them while sitting on its tires to ensure panel gaps remain consistent and your doors are functional. Normally I'd suggest putting it on 6-8 stands to get everything level, square, and plumb, but with a completed car, you've got all that paint to consider.
Posted By: Dr Dave
Re: Sub frame connectors - 12/23/14 11:03 PM
Thank, any one better than the other?
Posted By: Dan@Hotchkis
Re: Sub frame connectors - 12/24/14 01:52 AM
We think ours is the best.
Posted By: Dr Dave
Re: Sub frame connectors - 12/24/14 03:52 AM
Hi Dan, please give me the low down on your connectors. What level of chassis stiffness can I expect verses weld in and will they be visible looking at the car from the side, will I lose ground clearance ..... Thanks!
Posted By: Dan@Hotchkis
Re: Sub frame connectors - 12/24/14 04:36 AM
Quote:
Hi Dan, please give me the low down on your connectors. What level of chassis stiffness can I expect verses weld in and will they be visible looking at the car from the side, will I lose ground clearance ..... Thanks!
These tie the chassis together on a second plane and tie the rear subframe to the front subframe at the strongest points. They require minimal welding on the B/E cars. The lowest point of the connectors will be at the torque box, and they run about 1/4" from the floorpan. Here are the instructions for them which have a lot of good pictures that will answer a lot of your questions.
http://www.hotchkis.net/_uploaded_files/4011S.pdf
Posted By: roadrunninMark
Re: Sub frame connectors - 12/24/14 10:20 AM
Hi Dan, did your team ever investigate the possibility of making true "bolt on" connectors? Using your existing rear mount, the front would slide into the back of the torsion bar hex. I think a lot of people that don't want to alter their car wold be interested in a design like that. What do you think?
Posted By: Dan@Hotchkis
Re: Sub frame connectors - 12/24/14 03:12 PM
We looked at a lot of different options when designing our connectors. I don't think that we ever considered plugging into the back of the torsion bar slot, however that would be a lot of forces acting on the one part of the forward subframe. If it just plugged into the back of the socket I don't think that you would get a lot of fore-aft "anti banana" resistance. Couple that with the inconsistent depth that various manufacturers bars seat into the socket and I'm not sure that it would work out as well.
We made the forward end of the connectors modular because there are light inconsistencies on how much various cars have "settled" over the years. I've put these connectors in a LOT of cars and no two have been the same, and most require a bit of persuasion.
Posted By: 68KillerBee
Re: Sub frame connectors - 12/24/14 05:04 PM
Ill be getting the hotchkis one. I decided about 2 days after they had their big sale though.
Posted By: 4speeds4me
Re: Sub frame connectors - 12/24/14 07:27 PM
Posted By: Dr Dave
Re: Sub frame connectors - 12/24/14 07:34 PM
Can I expect my doors to open easily if parked on a bias or on the lift or is that too much to expect from a "bolt in" connector?
Posted By: roadrunninMark
Re: Sub frame connectors - 12/24/14 08:41 PM
4Speed, those looks nice... don't know how well they will work though, need some experts to take a look at them. Might even be able to make them for less.
Posted By: 68cuda440
Re: Sub frame connectors - 12/25/14 06:48 AM
Quote:
Hi Dan, did your team ever investigate the possibility of making true "bolt on" connectors? Using your existing rear mount, the front would slide into the back of the torsion bar hex. I think a lot of people that don't want to alter their car wold be interested in a design like that. What do you think?
Not that you asked me... but, I think the bolt in stuff is hokey. Weld them in. If you ever want to remove them just cut them out, grind the remainder back to the original frame, splash some paint on and its done. The Hotchkiss parts lend themselves well to this since you do not cut the floor pan and the rear part is bolt in.
-Michael
Posted By: 4speeds4me
Re: Sub frame connectors - 12/25/14 08:58 AM
Quote:
4Speed, those looks nice... don't know how well they will work though, need some experts to take a look at them. Might even be able to make them for less.
I think the seller is here on Moparts, but it's been a few years since I spent much time here...
Posted By: FASTBACK340
Re: Sub frame connectors - 12/27/14 04:37 PM
Weld them in and be done with it. I had picked-up a set of Competition Engineering pieces a while ago and just installed them 3 yrs. ago. They drop-down a bit, but no lower than the exhaust. E-brake cable passes above them without being re-located.
*This photo was taken before I removed those awful Flowmasters and installed the Chambered Mufflers
I did it to a finished car without incident. I felt the difference making the U-turn out of the shop that did the welding…..
Posted By: Dr Dave
Re: Sub frame connectors - 12/27/14 07:25 PM
Fastback, looks like yours are not welded to the floor correct? Are you able to park on a bias and still have your doors open easily?
Posted By: TC@HP2
Re: Sub frame connectors - 12/27/14 07:55 PM
Mopars are so bendy by this stage of their life that even simple 1x3 units welded to just the front and rear sub frames are a HUGE improvement over nothing. Are they the ultimate, no, but they are a big step in the right direction. Quite worrying about it and put them in.
Posted By: ahy
Re: Sub frame connectors - 12/27/14 08:37 PM
I had ART 2" x 2" connectors installed... similar to fastback's. Below the floor. They made a huge difference in how the car drove and how doors acted when jacking. As posted above, have at it.
Posted By: FASTBACK340
Re: Sub frame connectors - 12/28/14 02:46 PM
Quote:
Fastback, looks like yours are not welded to the floor correct? Are you able to park on a bias and still have your doors open easily?
They connect the sub-frames together. No issues with my doors, car feels 10X's tighter. Granted, I'm not running a Hemi, but it is a small-block stick that I enjoy driving.....
Posted By: 68cuda440
Re: Sub frame connectors - 12/28/14 11:54 PM
Quote:
Fastback, looks like yours are not welded to the floor correct? Are you able to park on a bias and still have your doors open easily?
Mine has subframe connectors (welded), torque boxes, 2x2 frame under the radiator, 1x2 frame across f&r of fuel tank for support. I have jacked up the car at the front corner and lifted 3 wheels off the ground... gaps on the doors and fenders did not move. The car is very rigid. Rust free Texas car if that makes any difference.
-Michael
Posted By: roadrunninMark
Re: Sub frame connectors - 12/29/14 02:01 AM
Would bolt on aluminum work as well instead of steel? I know they can be heavy, was thinking if you were going to make them, what about aluminum?
Posted By: MuuMuu101
Re: Sub frame connectors - 12/29/14 02:33 AM
Quote:
Would bolt on aluminum work as well instead of steel? I know they can be heavy, was thinking if you were going to make them, what about aluminum?
You could but for the same size tubing, you'll have a subframe connector that is about half as weak (depending how the metal is prepped). Not only that, but generally aluminum cost more than steel. Even butting to dissimilar metals next to each other is generally not preferred.
Posted By: jcc
Re: Sub frame connectors - 12/29/14 05:04 AM
Quote:
Would bolt on aluminum work as well instead of steel? I know they can be heavy, was thinking if you were going to make them, what about aluminum?
I'm counting the days until we start hearing reports about fatigue cracks in the now defunct XV welded K frames. Enough said.
Posted By: FASTBACK340
Re: Sub frame connectors - 01/02/15 11:25 PM
Quote:
Quote:
Would bolt on aluminum work as well instead of steel? I know they can be heavy, was thinking if you were going to make them, what about aluminum?
I'm counting the days until we start hearing reports about fatigue cracks in the now defunct XV welded K frames. Enough said.
I work with high-performance aftermarket parts daily and the range of quality reminds me of my Dune Buggy days in the 80's. Can't believe what people try to sell and what people continue to buy. 
Posted By: Dr Dave
Re: Sub frame connectors - 01/06/15 09:41 PM
I have decided to go ahead with the fully welded to the floor pan style and repaint the bottom. I'm sure I will be much happier and what the heck, it's only $$! Thanks for everyone's input.
Posted By: 68KillerBee
Re: Sub frame connectors - 02/26/15 03:39 AM
Hotchkis set showed up today, it will be a while before thereoj
Posted By: Dcuda69
Re: Sub frame connectors - 02/26/15 05:51 AM
Quote:
Mopars are so bendy by this stage of their life that even simple 1x3 units welded to just the front and rear sub frames are a HUGE improvement over nothing. Are they the ultimate, no, but they are a big step in the right direction. Quite worrying about it and put them in.
This guy gets it. I spent $50 on materials and a couple hours making it fit(I am by NO means a fabricator)and they made $500 difference! Don't over think it...tie them together and done!! You'll be glad you did! 
Posted By: astjp2
Re: Sub frame connectors - 02/26/15 09:17 PM
Posted By: dogdays
Re: Sub frame connectors - 03/03/15 08:48 PM
Thing to remember about aluminum is NOT the tensile strength, it's the modulus of elasticity. That is another way of saying spring constant, if that helps explain. Aluminum has a modulus of elasticity of around 1/3 that of steel. That means for a given amount of stress, the aluminum will deflect three times as much as steel. So to get the same stiffness, the aluminum part has to be three times as thick or whatever dimension matters most. That partially negates the weight savings.
This has nothing to do with strength, which is generally how much stress before permanent deformation.
If using aluminum I'd be much more worried about how to get a decent weld than the effects of dissimilar metals on corrosion.
R.
Posted By: 68cuda440
Re: Sub frame connectors - 03/04/15 06:51 AM
Quote:
If using aluminum I'd be much more worried about how to get a decent weld than the effects of dissimilar metals on corrosion.
R.
I would actually be more worried about life and fatigue. Steel is fairly straightforward. If you design the load below a given threshold the life is functionally infinite. Aluminum has no such threshold. That is why aluminum parts on air frames are replaced on a schedule. I have never designed with aluminum for service life (steel - yes), so maybe the Corvette engineers know something I do not. Just not so comfortable with an aftermarket aluminum frame. The life testing and level of vetting the OEMs do is not really attainable for aftermarket suppliers.
Posted By: Dans 68
Re: Sub frame connectors - 03/04/15 08:40 AM
Anybody try these?
US Cartools Bolt in Sub Frame Connectors It looks intriguing, albeit pricy....
Dan
Posted By: Supercuda
Re: Sub frame connectors - 03/04/15 02:10 PM
Quote:
Anybody try these? <a href="" target="_blank"></a> US Cartools Bolt in Sub Frame Connectors It looks intriguing, albeit pricy....
Dan
Read this first
https://board.moparts.org/ubbthreads/showflat.php?Number=7904856
Posted By: GoodysGotaCuda
Re: Sub frame connectors - 03/05/15 01:16 AM
Quote:
Quote:
Anybody try these? <a href="" target="_blank"></a> US Cartools Bolt in Sub Frame Connectors It looks intriguing, albeit pricy....
Dan
Read this first
https://board.moparts.org/ubbthreads/showflat.php?Number=7904856
I've talked to them fairly recently and expressed concern about their previous history. I was assured things were on the up and up. With their eBay store and being able to pay with PayPal, buyers should be fairly covered going that route.
Their Ebody chassis stiffening package is tempting..Chris Lewis is whom I was speaking with.
Posted By: Supercuda
Re: Sub frame connectors - 03/05/15 01:21 AM
Well, I dunno if they took care of the guy in the linked thread, but I felt the OP needed to know what he might be getting into.
Posted By: GoodysGotaCuda
Re: Sub frame connectors - 03/05/15 01:22 AM
Quote:
Well, I dunno if they took care of the guy in the linked thread, but I felt the OP needed to know what he might be getting into.
Yep, no doubt. I haven't spent any money with them, so I can't say one way or the other.
Posted By: Brian
Re: Sub frame connectors - 03/05/15 03:10 AM
I've installed the entire chassis stiffening kit on my Duster. No issues with the purchase or installation.
Posted By: GoodysGotaCuda
Re: Sub frame connectors - 03/21/15 12:47 AM
Quote:
Quote:
Well, I dunno if they took care of the guy in the linked thread, but I felt the OP needed to know what he might be getting into.
Yep, no doubt. I haven't spent any money with them, so I can't say one way or the other.
Ordered Sunday, showed up today.
