[XR7-4.6]

The front of the bird is so flimsy it’s not even funny how much flex is there. All you gotta do it look at the cheap spot welds on the shock towers. And I totally understand XR7-4.6’s point.Cars who use a strut tower brace were designed that way from the factory, to use those bars. Our cars were NOT designed with them in mind. One thing I will say is, all the bracing I’ve done has helped out a ton, and I don’t see why a little more reinforcement would hurt.
I currently have both braces under the front of the car, subframe connectors, REAR STB, rear lower cradle brace and I’ve also recently added a mark 8 X brace along with the factory V and L braces.and I can safely say that this car is stupid flimsy. View attachment 45748

I’ve been in MN12s with them and MN12s without them. I used to think 300lbs worth of of tubing bolted every which way did something, in fact I may have been an early endorser of the V and L bracing behind the rear seat(did it in 2007), but the cars I thought felt so good compared to mine, surely because of the bracing, turned out to feel the way they did because of the springs, shocks, sway bars, and tires. Sure enough, matching those one by one make my car feel the same with nary a brace added, including the non measure of stiffness by jacking the corner of the front and the rear tire lifting - yeah, my car does that too. Sway bars =/= Tower bars.

These aren’t the strongest chassis in the world but they are not flimsy. Least of which the front end which is full of interlocking box structures, flimsy to me is what you find in much older 60s-70s unibodies, where the fenders are structural and the frame rails serve as the primary structure, in fact it was these types of designs that facilitated the need for STBs in the first place. MN12 front structures are very modern, everything is anchored to the cowl structure from top and bottom. And as for cheap spot welds, cheap spot welds are the primary form of welding cars, even high end cars don’t have a stack of dimes to be found anywhere in a unibody, it’s about where they are, how many there are and if they get the job done. If the front end was half as flimsy as you say they would commonly be separated, right? Even on cars with severe rust where the sheetmetal towers under the fingers is gone you rarely see evidence that the shock towers separated and moved, you’d surely see rub marks between the hood and fenders, no?

As for Steeda, remember that this is an aftermarket company that began as a tuner/parts supplier for Foxbodies, a chassis that is, well, pretty legitimately flimsy. Mustangs have come a long long way since the 70s and the benefits of substance for the aftermarket in this area is diminishing every year that passes. Sorry but the braces you showed is Steeda selling snake oil to stay in the business of souping up Mustangs. A lower STB is absurd, traditional STBs at least have the benefit of the doubt that the towers can move via leverage, but there is no ******* way the frame rails are moving towards or apart to each other, not gonna happen.

 

[Wile E. Coyote Jr.]

These chassis arent flimsy. At all. On The Turbo Forum theres a couple guys saying they were super impressed with the cars when they had their hands on them.

The biggest downside of these cars are their weight. Roughly 800lb heavier than a pony car of the era. Plus the longer wheel base, not many picked the chassis for performance builds.

Can they be improved? Certainly. But just a single bar probably wont do much. And those bolted in bars with a little bit of flat stock holding them on wont affect it much either.
Youd probably get better results stitch welding the chassis, which Ive started doing, among other things.

But like Matt said: good suspension and tires will make the biggest difference. Not KYBs, cobra Bilstein rears and the Bilstein insert front and mod (since we dont have anymore options atm). And not some 300 Tread wear street tire. I mean Proxes, Ecstas, Azenis, Potenzas R71s.

Im not trying to knock you. I like where your head is at. But reevaluate the braces. Youve probably added 100lbs to you car and placebo affect could easily make you think they are helping more than they actually are.

 

[Noser7mil]

I agree with what you guys are saying, it’s not nearly 100lbs in bracing and I can clearly feel the difference ayer each brace that has been added to the bird. I mean back in the 90’s this thing was rock solid, but in today’s age. It’s a wet noodle for sure.
I have QA1’s up front, vogtlands 1.6 rears with cobra bilsteins, 1 1/4” rear sway bar, delrin bushings all in the rear and pretty much every bushings brand new with the exception of the rear upper control arms (I do have but suuuupper lazy to do) and aluminum IRS bushing aswell which I’m lazy to do too haha. And while yea, I would say the best thing to do on this platform is to freshen up THE WHOLE SUSPENSION first, then add mods. I wouldn’t even be able to imagine how my car feels without all the bracing I’ve added, I’d be scared too. The body acts like another spring! I’m sure I’d see a bigger benefit from stitch welding certain areas than these braces but that’s more time extensive and not a lot of guys out here want to do that. Chickens!

ive been trying to find this article maybe you guys can help me out. I’ll post a link it’s on an FN10 forum. Basically he explains the mn12’s body in detail.

Interesting Structural Analysis on the FN10/MN12 - Lincolns OnLine Message Forum

Interesting Structural Analysis on the FN10/MN12 Mark VIII Archive

www.lincolnsonline.com

 

[XR7-4.6]

Interesting Structural Analysis on the FN10/MN12 - Lincolns OnLine Message Forum

Interesting Structural Analysis on the FN10/MN12 Mark VIII Archive

www.lincolnsonline.com

The driveshaft critical speed and whatnot is the most useful part of that article, driveline was Jerry’s specialty afterall. However this part:

Now, in typical Ford fashion, the first year of new car, no expense is spared and all the good stuff is put in there to make the car right. Then the &^$* bean counters come along and say the car is not profitable enough and start to take out the good stuff that's in there. What I mean by this are things that are subtle that they can do to impove the body structure. Things like thicker mastic on the floor pans, structural foam in the rockers to stiffen up the car. While these are all band-aids for bad body structure, they are effective band-aids. The original Marks in '93 had this stuff, but it was quickly thrifted out by bean counters and complaining by the assembly plants that it was too hard to build.

…I have some problems with. First of all 94-97 cars are loaded to the gills with foam much more so than the 89s I’m very intimately acquainted with, the sound deadener mats(mastic) on the floor and trunk pans aren’t there on 89s. In fact the sound deadener in every 89-92 I’ve pulled the carpet of has it in an intermediate layer between the floor and carpet and I’m more convinced the switch to the glued on mastic was either to reduce costs of that extra layer of insulation or remove that layer for the corrosion potential it poses(it’s a sponge when wet) or both. I’m extremely dubious of the stiffening effects of those things, NVH yes, the foam would lessen the potential tin can effect of the steel when rocks and stuff hit it, that’s why they stuffed the rockers with it, that’s why that little narrow spot in the upper front frame rails at the tip of the wheelwell has it as well

Same goes for Marks, the only thing cheaped out on in them was switching from the one piece driveshaft in 93 to the 2 piece from 94-98. I have never seen the evidence inside the many Mark VIIIs I’ve gone through to confirm this supposed reduction of foam and sound deadener mats in 94-98s, they’re filled with the stuff just like MN12s.

As for the rear window area, maybe. I do firmly think the V brace or L braces should have been welded in from the factory instead of fastened(unfortunately they were compromises for the optional fold down seat). Lincoln did it right with the welded in X brace.

 

[Wile E. Coyote Jr.]

I personally believe that your efforts could be focused else where to achieve your goals more effectively. The mid ship flex is something we all know about, due to the 30in fuel tank shaped gap between the front and rear "frame" portions. Usually the issue is solved with a simple driveshaft upgrade, as discussed in the same article you shared. Others, me included, have go to crazy lengths in an attempt to make them very, very solid.

I have chosen to refrain from commenting further.

 

[Darin10]

As someone that doesn't know much I am gaining a lot of knowledge from both sides. What about the subframe connectors? I was thinking of making my own.

 

[S4gunn]

View attachment 45735 View attachment 45736
I was thinking something along the lines of this, he’s a local on the Facebook forum I believe. From the looks of it, he said it clears hood and all. Gonna look into it pretty soon, I’d REALLY LOVE ONE HAHA

The notch is hilarious. Ask yourself how much resistance that ruler sized strip of metal offers the shock tower mount points from flexing.

The owner will see better performance from their car by ditching the metal bar, properly airing their tires for the application, cleaning their car, skipping a meal and/or taking some laxatives to lose some weight.

 

[Grog6]

I think tying our front towers to the firewall will result in broken windshields, most likely.

 

[Wile E. Coyote Jr.]

my vote is stitch weld them and let everything else run its course.

 

[Noser7mil]

View attachment 45805 my vote is stitch weld them and let everything else run its course.

I wish!! I havnt got around to making the strut bar. I’m debating If I’m really willing to drill holes in my strut towers. I’m switching to a 4v soon and it won’t work so I’d rather not have holes there. I’m trying to see if I can use the shock absorber area to make it work.

The driveshaft critical speed and whatnot is the most useful part of that article, driveline was Jerry’s specialty afterall.

I was wondering if by any chance you’d know where I can find the rest of this article, I’d like to see what they have to say about this chassis and what ways it can be helped out. I’m sure the bird engineers could chime some light in terms of chassis rigidity.

 

[XR7-4.6]

I was wondering if by any chance you’d know where I can find the rest of this article, I’d like to see what they have to say about this chassis and what ways it can be helped out. I’m sure the bird engineers could chime some light in terms of chassis rigidity.

That’s all of it. It wasn’t an article, Jerry was on the forum way way back and that was a quote from a post he made at tccoa or birdcats or markviii.org 20 years ago. Keep in mind he was a powertrain engineer at Ford, he wasn’t part of the MN12/FN10 design team

 

[General Zod]

I’m debating If I’m really willing to drill holes in my strut towers.

Don't do it! Today I was looking at the car and I set the ol' noggin on ludicrous Wraith speed. Lo' and behold, nothing needs to be drilled to add a stout, but lightweight FSTB (using 4130 chromoly of course). It will require some custom-made parts however, but I think it will be really tight. I need to gather some parts, coincidentally all my old original stuff that I thought I'd never need and literally threw in the garbage, well now I need it back to check clearances and what not! LOL. Funny how I now have to pay someone to buy all my old junk back, lol. But yea the faster I can buy the used parts I need, the faster I can solidify my design into reality. Now to post another Wanted Ad...