Deleting The Convertible's Rear Chassis Braces

Sky Render

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Here's something I've never seen before, and can't seem to find now either. Apparently these are made by Stifflers, however, I can't find them anywhere on their site. Has anyone seen these before?

That has to be the crappiest chassis "bracing" I have ever seen.
 

Benwhite911

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So after a little more digging, I found out that these braces are from the Cervini's Side Exhaust Kit. This one being specifically for the Convertible models, part number TMC-001 . The Factory Chassis Braces get in the way of the side exhaust, so these are offered as a replacement for them.
 

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Benwhite911

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I do not have the engineering or "scientific" data to back up my thoughts on this.

But, I have always had a very hard time accepting that the OE braces do much of anything.

1: They are not very strong.

2: They are bolted on via weak hardware.

3: Where they attach to, the sump/tire well is a very weak area.

4: If torsional rigidity is the purpose - I fail to see how they are effective when they span from the outboard subframe area and mount inboard close together. When we design a chassis stiffening part, especially for something like this particular part, we would want it to spread wide and triangulate together. When you mount a "brace" to an area of the car you want more rigid, why would you mount the two individual pieces so close together?

As you will see in the picture above of the aftermarket braces - look how narrow. Would the chassis not easily be able to "roll" or "pivot" around those "braces"?

I have no engineering background myself so I can't really comment as to why they were put in place to begin with, or why Ford continues to put them on the convertible Mustangs. I had just always assumed that it has something to do with adding additional protection in the event of a rear end collision, due to to the lack of a supporting roof line to absorb impact energy.
 

Sky Render

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As someone else pointed out, the convertible chassis bracing is primarily to reduce NVH.

The only way to really strengthen a convertible is to add a roll cage.
 

Benwhite911

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Well it's been over two weeks now since I've removed these braces. I haven't noticed anything really all that different with ride, comfort, or NVH. One thing I can say that was beneficial to having these things off was changing my rear springs. I was having a "just cuz I felt like it" moment, and swapped out my rears for a higher rate. Before it would have been a 2 to 3 hour affair. Yesterday, up and down, 40 mintues.
 

2007Vert

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I removed the factory braces off my convertible GT500 and noticed no difference. They do not add any value IMO. When I added the Trinity blower BMR subframe connectors were installed to stiffen the chassis.
 

FrankieD

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I notice mine are rotten (Chinese steel probity) took hem to my buddies fab shop they said they are going to make them out of bar stock and make them a lot stiffer.
 

FrankieD

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I have 09 convert mine are rotten so pulled them because I was pulling the axel housing out to get new gears put in and have the housing sand blasted and painted, thing looked like it was 80 years old more Chinese steel. I took the braces to my buddies fab shop and he is going to make new ones, not worth the $500 I seen being asked for on some sites. They aren't much support but better than nothing.
 

OldMuscle

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Short answer: If this mod doesn't light your fire then your pilot light is out!
In the next couple of weeks, I am planning on a tires / brakes / shocks upgrade on this 2007 V6 convertible that I bought last winter (103,000 mi). Having never owned a mustang before (An early model F-body gear head from way-back) I didn't really know how these cars were supposed to handle so I decided to start the mods from the ground up with some chassis improvements including the convertible braces. My convertible braces were in decent shape for their age yet did show one small corroded/weak area. Step 1: Last Friday I had the Stiffler FIT chassis brace system welded in at the Stiffler mfg plant . Brian and Mike also installed their latest prototype convertible braces and their adjustable panhard bar. I'll need that adjustable bar because I am installing Vogt 1.2" lowering springs along with (once they arrive) Koni non-adjustables all around.
The change in handling with the both the Stiffler Fit system and the new convertible braces is nothing short of amazing. As I said at the outset: If this mod doesn't light your fire then your pilot light is out!

The car, although in decent shape, is all original and all stock (except for the Aeroform bar, Pypes true duals and a rebuilt alternator added by a previous owner). When I say original - I mean original - it still has the factory installed struts and shocks. Obviously, with 100,000+ miles they need replaced but the change was nothing short of phenomenal. My 25 year old son ran an errand with me on Saturday and without my prompting said ... "This is amazing! It rides like Mrs. Reynolds BMW... What do you mean? You have to watch the speedometer in her car because it's so smooth you don't realize that you're doing 90mph. There is a huge change in how your mustang rides just going down the road." I just smiled ... mission accomplished.

While I am waiting for the Koni's to arrive, I am going to remove the convertible bars and install the rear GT500 13.9" rear rotors and take it for a drive. I'll report back if there is any significant change without the braces. Here are some pics that I took at Stiffler's during the install. Brian and Mike were phenomenal ... the kind of people that I want to do business with.
I'll upload better photos when I have it up in the air but the last photo is just the attention to detail on the install of the Stiffler FIT system - they retained the stock plastic corrosion guard by trimming to fit (pic 3: view just below the drivers seat)
Staying on topic - if you're looking for replacement convertible bars, Stifflers is adding their improved version of the Convertible braces to their product line (they had a prototype but used my car to take jig design measurements) and it will work standalone as well as integrate directly into the Stiffler FIT chassis system. I don't work for them and met them as a result of this post as I was researching what to do about my compromised convertible braces. Call him: Brian can tell you himself how he changed the box orientation to increase the stiffness so it's now more than just a harmonic dampener. Will advise... Stiffler Vert Brace1.jpg Stiffler Vert Brace2.jpg Stiffler Fit.jpg I will post additional pics as the tires/brakes/suspension upgrade moves along during my 2 week COVID furlough.
PS. Take a close look at the mounting point of the Convertible braces at the lower control arm mounting point ... It looks like a Torque Box brace design but this setup integrates through the unibody to the rear subframe section.
 
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