Subframe Connectors

[Mach1 Driver 560]

This has been the go to results for quite a while. I don't think anyone has done more comprehensive test.

 

https://www.stangnet.com/mustang-forums/threads/torsional-rigidity-test-67-coupe.723029/

WOW, thanks for the really-really excellent link RPM.

There are real test results here in a very long thread running over 5 years. There is a summary in post #79.

 

My guess about torsional effects are borne out by the testing: subframe connectors do zero to reduce front to rear torsion. An Export Brace will reduce torsion by a whopping 25%, a rear seat divider by 11%, a Monte Carlo bar also by zero.

 

I'm going to look into the footprint of the Spin Tech SFC but only because it may provide a good rear jacking point for my short armed two post lift.

[1969_Mach1 333]

This has been the go to results for quite a while. I don't think anyone has done more comprehensive test.

 

https://www.stangnet.com/mustang-forums/threads/torsional-rigidity-test-67-coupe.723029/

I certainly don't have anything better to offer.  But I wouldn't base my decisions on that backyard test.

 

NOT MY THUNMBNAIL

[Mach1 Driver 560]

I certainly don't have anything better to offer.  But I wouldn't base my decisions on that backyard test.

 

NOT MY THUNMBNAIL

It IS the only test results I've seen, and it may be a backyard test, but the design of experiment appears valid, and he moved the jack points to further refine the test with input from forum engineers. Given the conditions I think it was executed brilliantly and gives actual results on the rigidity of the unibody as changes are applied.

You are one of the more technically savvy members of the forum and actually worked in the industry so I respect your opinion. You mentioned that you don't have them on your current Stang, but probably have lots of anecdotal information that they (SFCs) do something. They don't appear to do anything torsionally, but may strengthen the car as a beam. I'm just not sure how that would help. Any insight as to what they do to the feel of the car, since that appears to be all we have to go on? 

[Rsanter 152]

You can also install the convertable inner rockers

I have done this on a number of cars and the cool thing is that most people don't seem to realize it was done.

 

There is some other types of body bracing you can do as well that can be nearly hidden but they require specific fabrication to do....but then I live the whole sleeper idea

 

Bob

[Mach1 Driver 560]

You can also install the convertable inner rockers

I have done this on a number of cars and the cool thing is that most people don't seem to realize it was done.

 

There is some other types of body bracing you can do as well that can be nearly hidden but they require specific fabrication to do....but then I live the whole sleeper idea

 

Bob

Do those go inside the car?

[moodster 55]

The convertible inner rockers go inside the car right behind the visible part of your current rockers.  They are difficult to add in since they join with the rear sub frame and go inside your existing torque box.  Additionally you'll need new carpet and several other pieces to complete the upgrade to your interior.

 

david

[Mach1 Driver 560]

The convertible inner rockers go inside the car right behind the visible part of your current rockers.  They are difficult to add in since they join with the rear sub frame and go inside your existing torque box.  Additionally you'll need new carpet and several other pieces to complete the upgrade to your interior.

 

david

 That does sound like a good way to add rigidity. Just curious, do convertibles take different carpet kits because of these inner rockers? What other stuff is needed?

[RPM 1,190]

This is an excellent how to article on what all is involved to install convertible rockers.

 

http://www.streetortrack.com/Installing-convertible-rockers-into-a-65-68-p-14.html

[MikeStang 247]

_{I have driven mustangs without sub frame connectors and with them...the ones with them always feel tighter in handling, they will seem to hold the corners better and the ride is firmed up.}

_{Not to mention if you are hooking up any at all without them your door to fender gaps will get larger and larger as time goes by.}

_{I liked the back yard testing the guy did, it sheds some light on things and also put some thoughts in my mind in terms of upgrades.}

 

_{They mentioned something about having another structure brace above or below the frame rails adding strength, So I was thinking about possibly a weld in bar under the dash tying into the front Torque boxes and going from one box to the other while staying completely inder the dash near the cowl area....Kinda like a Shelby roll bar under the dash....Think there would be room for it.}

_{I will be installing a rear seat divider for sure}

[prayers1 153]

I have a fold down rear rear so the rear seat divider is out of the question.

What do you guys think of Heidts or Total Control.

I like that the Total Control has a provision for a driveshaft safety loop.

 

I didn't see much hype about the shock tower reinforcement kit.

So is it just a waste of time welding those in if your shocks towers are good and use the Monte Carlo Bar and Export Brace?????????

[Mach1 Driver 560]

I have a fold down rear rear so the rear seat divider is out of the question.

What do you guys think of Heidts or Total Control.

I like that the Total Control has a provision for a driveshaft safety loop.

 

I didn't see much hype about the shock tower reinforcement kit.

So is it just a waste of time welding those in if your shocks towers are good and use the Monte Carlo Bar and Export Brace?????????

Heidts and TCP are just different versions of long torsion bars as far as I'm concerned. They can't hurt but I don't see them doing much.

I would look at the reinforcing kit as insurance to keep the shock towers healthy.

[prayers1 153]

I see that they are round tube and claim they do not twist like square tubing. 

I'm not an Engineer, but IMO I would think it would be easier to twist a round tube vs. square.

 

Any opinions on that?

[det0326 179]

Anyone that has had a tinman's sub frame connector in there hand would tell you it is an overkill.  It is more rigid than what it is connected to on our cars. Now if you add a couple of braces from the SFC over to the inner rocker now you have managed to make it the strongest part of the whole structure. 

[RPM 1,190]

I don't remember if the article addressed the shock tower reinforcement, but maybe it is for forces other than tortional. To do or not to do the reinforcement. For me it would depend on the condition of your shock towers, if your have a big block or not and the intended purpose of your car. If you have the engine already removed I'd do it. But if your towers are in great shape, you have a small block, the engine is installed and your car is driven sanely I would not ad the reinforcements.

 

Round tube is typically about 20% lighter for the same overall diameter than square tube. Square tube is stiffer, but on paper for the same weight of material round tube would always win. And square tube is a lot easier to cut and weld, especially for complex angle joints. So maybe the manufacturing process is why one shape is chosen over the other.

[Mach1 Driver 560]

The article didn't talk about the shock towers because he eventually removed them for coil overs. I think the reinforcing kits are just good insurance for a part of the car that takes a pounding from many directions and eventually fatigues.

Chrysler torsion bars were 0.960" diameter of unspecified wall thickness- and obviously designed to twist a lot. A SFC that is 50-60" long will twist- the only test available (above) shows that they do nothing to prevent torsional motion. They must do something but human nature being what it is, could you really tell (before and after) that they were on the car if you didn't know they were added? Would you say "hey something is different"?

The convertible rockers would probably do the most but are very difficult to install- the front suspension has to come off and the front of the torque box removed, a hole cut and the rocker passed through it into the car. Then everything is welded-up. Its a major addition.

Like I said before I think I'll add the Spin Tech SFCs, but just because they provide a good lift point for my two post lift. If they stiffen the car up then they have an added benefit.

[Machspeed 219]

Anyone that has had a tinman's sub frame connector in there hand would tell you it is an overkill.  It is more rigid than what it is connected to on our cars. Now if you add a couple of braces from the SFC over to the inner rocker now you have managed to make it the strongest part of the whole structure. 

"Overkill".....exactly! 

[MikeStang 247]

I have always wondered why someone doesn't make a sub frame connector that cradles the front frame rails and runs all the way up to the torque boxes and ties in like I did the connectors that I built for my 66.. "Pics posted somewhere on here"

I built my SFC for the 66 out of 3x3 Square tube and they are pretty damn sturdy but I knew they were major overkill but since I had the material left over from the rotisserie build why let it go to waste :)

 

I didn't know the rear divider couldn't go in if you had a fold down rear seat... looks like I wont be running a divider once I install my fold down LOL.

 

I saw where the guy installed the M2 cross-member like I have but I wonder if it would help the torsional flex out if you were to cut some stiffener plates the same shape as frame rails and weld them to the sides of the rails on both sides and tie them into the cross-member some 1/8" or so would be easy to cut out and add on and I happen to have a 1/2 sheet left over that is doubling as a parts bench LOL.

[Mach1 Driver 560]

I saw where the guy installed the M2 cross-member like I have but I wonder if it would help the torsional flex out if you were to cut some stiffener plates the same shape as frame rails and weld them to the sides of the rails on both sides and tie them into the cross-member some 1/8" or so would be easy to cut out and add on and I happen to have a 1/2 sheet left over that is doubling as a parts bench LOL.

sounds like the metal is calling to you...show us pictures when its done

[prayers1 153]

I have been fighting with the decision of putting in the Shock Tower Reinforcement.

I have good shock towers and was going to just use the Monte Carlo Bar, Export Brace, a Beefier Cross Member and Tin Man Subframe Connectors.

I occasionally street race but most of the time just cruise. Right now the drive train is out, waiting for the 4000 rpm stall converter to come in. Motor is a 408 Cleveland Stroker, 520 hp/ 480 tq.

 

Do you guys think its really necessary to install the reinforcement Kit?

 

I really don't want to do it and I'm no expert or have this experience with a stronger motor in this year mustang.

[BuckeyeDemon 211]

I have been fighting with the decision of putting in the Shock Tower Reinforcement.

I have good shock towers and was going to just use the Monte Carlo Bar, Export Brace, a Beefier Cross Member and Tin Man Subframe Connectors.

I occasionally street race but most of the time just cruise. Right now the drive train is out, waiting for the 4000 rpm stall converter to come in. Motor is a 408 Cleveland Stroker, 520 hp/ 480 tq.

 

Do you guys think its really necessary to install the reinforcement Kit?

 

I really don't want to do it and I'm no expert or have this experience with a stronger motor in this year mustang.

 

for reference, there are some other opinions in a thread about the shock tower reinforcement.at the following link:

 

http://1969stang.com/forum/index.php/topic/55342-is-it-necessary-to-reinforce-shock-towers/

[prayers1 153]

Yes I am familiar with that thread. For some unknown reason, since the beginning of this new website, I'm having a hard time finding previous threads I started with this Sites SEARCH Box, Thanks for finding it!

 

AS you all can see I'm still on the fence with this decision. I'm definitely putting in subframe connectors but the Shock Tower reinforcement is a different question.

 

I'm leaning towards the Tinmans with the diveshaft safety loop.

[LoneWolf2U 136]

Well lets look a what Ford did when they started dropping higher Hp/Tork engines in these cars.

They did reinforcing! It is a better to have it then need it later when your tork twists the sub frame out of wack.

As you stated your waiting on parts an the space is open to make the install easier. So do it now and not have to restraighten the frame rails later and do it then.

[moodster 55]

I'm definitely putting in subframe connectors but the Shock Tower reinforcement is a different question.

 

If you're not racing and you don't have say over 400 hp then I think you would be fine with just what Ford gave the car from the factory.  I do these upgrades when the opportunity arises.  The shock tower reinforcements are good to have so I did them when I rebuilt my front suspension.  Subframe connectors are good so I'll do them when I detail the undercarriage (someday hopefully).  Until then I drive the car like I stole it and don't worry about it.

 

Note that I've only ever seen unibodies get twisted when they are seriously drag raced.  You can generally tell just by looking at the roof... it'll have ripples in it.  You really have to make the car hookup to put that much torque through the center of the body.  I've never seen a hardtop/fastback sag through the middle even ones with rotten floors... now convertibles, yes, most of them droop in the middle.

 

david