fvike

Dude! I feel your pain. I actually turned away when I saw that first crash picture. DAMMIT THAT SUCKS!!

Mine would have looked just like yours out of the factory.

Built at Milpitas 12/26/68.

Yeah, I agree.

I don't think they are flush. There's a gap that is covered by the bumper. They need to match at the wheel arch. This is a repro valance. The OEMs fit better.

The headlight bucket isn't supposed to be all one color. It should have a black-out area, painted by a brush. https://pin.it/cjyaxgzwhnsn63 http://www.concoursmustang.com/forum/index.php?topic=9875.0

Nope. '69s got marker lights in them. '70 marker lights is in the fender.

I think the meaning of post #24 is that the method applied is wrong. As in adding SFCs will do nothing for radiator support flexibility. I can very well believe that. But it will do a lot for the chassis. And the method applied misses that. The setup is the problem. The frame is supported by 3 jack stands. The whole of the chassis isn't available for flexing because it is locked in place. He is just measuring flex in the front frame rail, not the whole unibody. When the shock towers and Monte Carlo bar was in place, that load was spread across a larger area. When removed, and the same force applied will show more flex because the area it is applied to is less (limited). The 25% torsional stiffness credited to the MC bar isn't because the MC bar is so immensely strong. It's just a piece of steel. It is because the MC Bar allows the frame rails to be connected to a larger area. He should have put the car on it's suspension, but with strut rods instead of shock absorbers and springs. That way, the frame itself would not be supported at any given point, and free to flex all the way from front to back.

Did you see all the videos? There's a playlist with 13 episodes. Ep 9 shows retesting at Multimatic for damper tuning. The Videos show re testing on the 4-post rig, and the Multimatic people at the track for real world testing. The job was done right. No, they do not give away their test results, just as they don't with the spring rates and the damper valving. That way a competitor would get them for free. I'm sure the hours at Multimatic wasn't free. I'm telling you, all you have to do is drive a car before and after getting SFCs installed. If you have, we wouldn't have this discussion. It is a night and day experience. The Barracuda and the Mustang have differences, but they both are unibodies with separate front and rear framerails. How supposedly one benefits form SFCs and the other don't, you'd have to explain to me. Well, apart from removing the shock towers. All the testing done in the "garage test" is meaningless according to post #24 on that tread.

The main difference between the Barracuda and the Mustang, is that the Barracuda uses torsion bars instead of coil springs. So the tower of the Barracuda is a lot smaller, 'cause they only house the dampers. The transmission tunnel support is quite a lot beefier, because it houses the torsion bar housings too. The Barracuda does not have torque boxes, only the Hemi cars had that. My brother's Barracuda does not have torque boxes. The XV Motorsport kit that was sold to the public did not have the boxing of the upper rad support shown in the videos. They did have a Monte Carlo/Export brace that was mounted to the inner fenders and fire wall. All in all, I'd say the Barracuda weaker in stock form. I remember driving My brothers car when it was stock. On S-corners with a lot of camber, the fenders would visibly lift and dip. It was very soft in the front. This was with a 340 small block. The rear is quite strong. The Barracuda actually have a roll-over protection bar just over the rear window. So my experience with both cars is that the Barracuda was a worse starting point, and that the modifications XV did is applicable to the Mustang. Sean Hyland made at least a Mustang prototype with the XV suspension. I think it was a '66 Fastback. But the XV stuff was very expensive, so they didn't sell in the volumes they needed to survive.

It's all there in the videos I linked. It shows all the development of the suspension packages. The result of the testing was that they used SFCs, rad support bracing and shock tower-to-firewall to improve torsional stiffness. If the guys with the resources tell you SFCs works, and the guy "without" resources tell you they don't, who are you going with?

As I said, I don't have much faith in that test. I do have faith in Multimatic's 4-post chassis rig.

I disagree. LOL :D

True. But in a crash, we are talking about kinetic energy. It will dissipate by taking other forms like heat or sound. It's not like the impact (force) of the crash bounces around like in a pinball machine until it can bend or break something to bleed off energy. Crash force is one thing, it is what it is. The energy in that force is another. But we are getting off topic here.

Well, that is a entirely different thing. Force going from the bottom up, not thru it front to back. It's like a empty coke can; it is immensely strong up and down. If you balance right, you can stand on it with one foot. If you do that and tap the other foot on the side of it, it will crumble instantly. It's just the can or part doing the job it was designed to do, then it is strong. Put some other force on it, and it's weak.

My thinking is opposite. I would prefer the energy to dissipate thru the strongest part - the frame. I would not like the sheetmetal of the roof and floor to handle the impact forces. There is a more direct line thru the car with SFCs, instead of going thru the torque boxes and rockers. But now we're talking head on energy handling, not twisting motion.

That is impressive. My car did not do that. But it's been known for a long time that drag racers prefers the coupe over the fastback due their stronger construction. I'd like to see this on a stock fastback. As an engineer, do you agree with my thinking in the above post? About load paths thru the unibody I mean. It is at least the way I understand what happened to my car in the crash, and my reasoning around it.

I have to ask; did you replace them due to rust, or due to dis-forming? I studied the damage to my Mustang after my crash, and I studied the load paths the energy of the impact had taken thru the chassis. The crash: rotated into an armco section on the left side of the roadcourse with the passenger side front corner of the car hitting first. Eyewitnesses said the rear of the car was 1 meter off the ground and recoiled back out of the armco. So not the hardest lick, a hit to the driver side front corner would have been much harder. Pictures of the crash damage is in my build thread. The damage: Pass side framerail bent, radiator support bent, top of cowl on both sides bent (which is why I installed Boss 429-style supports after). The top radiator support was twisted. That means the load path went thru the frame rails and back, and thru the shock tower, thru the export brace and bent both corners of the cowl. Everything in front of the firewall needed to be replaced. The floor support did not. There was enough "real estate" that direction because of the SFCs to "bleed off" the energy. I can easily believe that without SFCs, the damage to the car would have been greater, because the load path would have ended at the floor support. The energy shockwave of the crash would have nowhere to go. The SFCs made it so that the energy could be taken up by the whole unibody structure, not just the front half. As we know from racing, crash protection is all about dissipating energy. The more structure you have to dissipate that energy into, the lesser impact the energy will have. The stock Mustang unibody is two structures, front and back frame rails. With welded SFCs you have one structure. The floor support is tied to both the transmission tunnel support and the rockers thru the torque box. The front frame rails is cradled by the floor support, and the floor itself boxes them off. I found them undamaged by my crash, and I believe they are stronger than given credit for. EDIT: Or are they made "stronger" by SFCs because crash energy can pass thru them, not end in them? So it is in my opinion wrong to think of the floor support as a weak part - which a U-shaped rail is - but one has to think of it as a whole structure. It is in fact the part that ties the car together. Frame rails, torque boxes and transmission support is tied into it, and SFCs when added. I like this picture, because the different part are in different colors and shades. It shows the frame rails, torque boxes and transmission support tied together by the floor support. Pictures of floor supports and installment of new frame rails.

I have not tried that. The X-brace is the anchoring point of my torque arm, so It's never been off the car (while driveable). I can do it for you if you find it important that I do, but per now, I do not have the windows in the car. So it will have to wait until I do. My brother's 'cuda can perform the same "3-wheel trick", and it does not have an X-brace. It does have SFCs cut to the underside of the floor, and welded entirely, except for a window to let the parking brake cable pass thru on the driver side. This is the underside of that car.

First off; I'm not an engineer, I'm not trained to do the math on this stuff, but I do have eyes. Having read trough this thread, I've come to the conclusion that the premiss of the discussion is wrong. The premiss that SFCs have zero impact on torsional stiffness. The test that is being laid to ground for this discussion (link) is a '67 coupe that has it's shock towers cut out (removing the export brace, which is alone 25% of the torsional stiffness, according to said test.), and then uses bolt-in SFCs. It is in my opinion the absolutely worst thing one can do to a unibody car. The torsional stiffness is now all in the roof (without the help from the export brace) and floorboard, and a few bolts. The test has absolutely no value for modifying a stock unibody Mustang with shock towers. The only thing he documents is how removing the shock towers kills the torsional stiffness of the unibody. Edit: The windshield and backlite should also be in the car when testing for torsional stiffness. They are a huge part of the cars construction. I say this, because in my experience, making a Mustang handle, is all about stiffening the platform (unibody) and reinforcing the shock towers, so that they don't move around. That is why we have the big block shock tower bracing, the boss 302 shock tower bracing, the triangulating of the top of the shock tower with the export brace and the Monte Carlo bar. And for the Boss 429, the shock tower-to-firewall brace. Think about it, all racing modifications on a Mustang is about minimizing flex in the shock towers. So how will that car perform when you remove the shock towers all together? Over to the SFCs. We all know, if you put a jack next to any given wheel on a stock Mustang, and jack it up, that wheel will come off the ground, and the 3 others will remain on the ground. I have the TCP SFCs with the X-bar installed on my car. When I jack up my car, 3 wheels will come off the ground, and the wheel diagonal to the jack will remain on the ground. There has to be some torsional stiffness there, right? I can see it. Also, I've said this before in other treads; when I installed my TCP front suspension, I drove the car a few days before I installed the SFCs. It was not until then, I felt that I had a new suspension on the car. It felt the same as stock without the SFCs. Again, that tells me they do something. So, those are my claims; I better back it up. My brother has a '70 Plymouth Barracuda, with the XV Motorsport level II suspension. XV didn't do anything half-assed when they developed their stuff. They went to Multimatic, to get the Mopar E and B-body torsion tested on a four post rig, and to then develop the suspension. They found torsional stiffness to be on par with modern sedans, and wanted to get them ut to sports car standards. They did it with a boxed front radiator support (like the Mustangs have), shock tower-to-firewall braces, and SFCs. Their SFCs is laser cut to follow the floorboards, and are fully welded in. You can see this on episodes of Dream Car garage, ep 2, ep 3 and ep 4. It's very cool stuff. My brother's 'cuda is like my Mustang, jacking it up will lift 3 wheels. Here is another proof for my claims. These pictures show my car hanging on a rotisserie, mounted at the rear bumper mounts and the front bumper arm mounts. It is hanging upside down with mint door gaps. It has all the shock tower braces (big block, Boss 302 and Boss 429 style) and TCP SFCs (minus the X-brace) It does not have the Monte Carlo Bar and Export brace installed. The chassis is of course bare, with no extra weight. I'll dare to claim, that a stock unibody Mustang could not do that. I do not believe that SFCs do zero for torsional stiffness, at the proof is in the XV Motorsports videos, where a world leading company like Multimatic is performing the tests on state of the art equipment. If you don't know who Multimatic is, they helped develop the new Boss 302 and the new Ford GT. On the discussion itself, I belive the convertible rockers will make a difference, but the car should have rear torque boxes as well. But I believe SFCs will do a better job for less money and work.

Yes, but it is very easy. Simple bolt-off.

I'd start with replacing the LEDs with the stock bulb. If both works, you know the fault to be in the driver side LED.

If it is the orange wire in this picture you're talking about, it is not connected to the AC/Heater system. It is for the cigarette lighter. It's always hot. All orange wires in the AAW harness is hot. The orange wires pictured above by Mike65 is not, they are a part of the Ford harness.

No, it gets replaced by the brown wire. Wire 50 in Branch 6.

If you do have the original harness: looky here... http://1969stang.com/forum/index.php?/topic/48318-crashed-my-fastback-the-rebuild-thread/&page=19