[1SICK5.0VERT]

When i first got my vert and i would drive it with the top down around town on uneven/bumpy roads i felt quite a bit of flex in the chassis, so i wanted to stiffen it up as quickly and easily as possible without having to weld because im not a very good welder. So the first step was to install a front mount strut tower brace. I had a hard time finding one that would fit with my cobra upper and lower but with some help of my fellow mm people i found one that fit perfectly. After the installation i took the car on a cruise and immediatly felt a difference but the rear still felt a little sloppy so i started looking into subframes and rear mount shock tower braces. So after purchasing some full length subframes i got really curious about the rear mount shock tower braces i saw on ebay and decided to purchase one. I received it a couple days later and wondered if i just wasted my money because i really couldnt see it working as it was advertised but after installing it i was blown away! The difference was night and day and i am extremely happy with the purchase. BETWEEN THE FRONT AND REAR TOWERS NOW BEING TIED IT HANDLES LIKE A NEW CAR AND EVEN BETTER THEN MY COUSINS SN95 HARDTOP WITH THE TOP DOWN! I have yet to install the subframes but the way it handles now im in no hurry to do so.
Thanks for reading!

[johnGT]

I may have to look into those rear shock braces. sounds like a good idea actually.

P.S. I don't think there is any difference with top up or down with body flex. I have never noticed a difference anyway..

[1SICK5.0VERT]

Originally Posted by johnGT I may have to look into those rear shock braces. sounds like a good idea actually. P.S. I don't think there is any difference with top up or down with body flex. I have never noticed a difference anyway..

hmm im suprised you dont feel any difference in ride quality with your top down. i definatly noticed a difference on mine. maybe i tweaked it at some point?

[johnGT]

Well I mean there is a slight difference I guess.. Still, the two metal foldable bars and cloth top aren't actually doing much.

[Bullitt95]

With no roof to provide structural rigidity, the vert has a lot more chassis flex than the coupe and needs all the help it can get to stiffen the chassis. I'd consider SFCs essential on SN95 verts and ALL Foxes.
If you felt such a difference just with the strut tower braces, imagine the difference you'll feel when you tie the subframes together as well.

[NFChaos2003]

As stupid as this may sound, I think my vert handles better with the top down. I think having the weight down on the rear wheels is helping out but I might be completely wrong.

[1SICK5.0VERT]

I was more so talking about the sloppiness with the top down. It just seemed to creek and rattle alot more without the strut and shock towers. I agree on the sfconnectors just havent had time to install them yet. Im sure its gonna feel solid as a rock with those installed too.

[ryanw]

lets see a picture of it installed...and a link to the product

is it only for verts ?

[johnGT]

They have one at summit racing. Not sure if it's the same brand, etc.

Steeda 555-5751 - Steeda 1979-2004 Ford Mustang Shock Tower Braces - Overview - SummitRacing.com

[1SICK5.0VERT]

Originally Posted by ryanw lets see a picture of it installed...and a link to the product is it only for verts ?

pm me and i will send you some pics via email. Theyre for hard tops and verts.

[1SICK5.0VERT]

Originally Posted by bullitt95 with no roof to provide structural rigidity, the vert has a lot more chassis flex than the coupe and needs all the help it can get to stiffen the chassis. I'd consider sfcs essential on sn95 verts and all foxes. If you felt such a difference just with the strut tower braces, imagine the difference you'll feel when you tie the subframes together as well.

finally got the full length subframes welded up with added torque box reinforcement plates. It feels amazing now in the twisties and i dont even feel any flex in the chassie any longer. With the front strut tower brace, lower k member brace, rear shock tower brace and the flsfconnectors this thing is as rigid as can be and i cant wait to autocross it! All i have to do now is install the new springs, shocks and struts and im ready!

[99FiveOh]

Do the 94-98 verts come with those bolt in subframe connectors like the 99 ups have? I have them on my car, they are kinda thin walled but better than nothing I suppose. I do intend to do full length subframe connectors on my car eventually but the ride is nice as it is. My K member X brace wouldn't bolt up after I swapped the 5.0 K member in so I need to source one from a 94/95.

[ReverendDexter]

Interesting... because I have FL-SFCs and regularly AX my convertible, and I just took my MM 4-pt STB *off* and felt no difference in handling/creakiness/etc.

[1SICK5.0VERT]

Originally Posted by ReverendDexter Interesting... because I have FL-SFCs and regularly AX my convertible, and I just took my MM 4-pt STB *off* and felt no difference in handling/creakiness/etc.

hmm... i guess the flsfcs work better then i would have thought then. maybe the flex i have been feeling was coming from in between the front and rear subframes all along?? all i do know is i felt a difference with the braces installed and i even felt a bigger difference with the flsfcs installed. i cant see how the stb and the shocktb wouldnt do anything? i would think anything that helped tie the car together would help even if minimal. but hey even if they dont help much they do add some bling lol!

[ReverendDexter]

Originally Posted by 1SICK5.0VERT i cant see how the stb and the shocktb wouldnt do anything?

Really? I'm 180 degrees away from that... I can't see that they do anything, lol.

What lateral force is acting on the top of the strut or shock towers that those braces will resist?

There's definitely lateral load on the *bottom* of the k-member coming from the A-arms, which is why they sell k-member braces. But on the top? It's all vertical, which an STB does nothing for.

For the shock towers, again, where's the lateral load? Anything the tires experience is going through the control arms and hitting the torque boxes, but bracing the top of the shocks? There's just nothing there.

Now, if someone can show me what force those braces work against, I'm all for 'em. But I just can't see it.

Now, FL-SFCs, zomg that's a HUGE difference. Any fox-chassis car I own, that's the first mod.

[1SICK5.0VERT]

Originally Posted by ReverendDexter Really? I'm 180 degrees away from that... I can't see that they do anything, lol. What lateral force is acting on the top of the strut or shock towers that those braces will resist? There's definitely lateral load on the *bottom* of the k-member coming from the A-arms, which is why they sell k-member braces. But on the top? It's all vertical, which an STB does nothing for. For the shock towers, again, where's the lateral load? Anything the tires experience is going through the control arms and hitting the torque boxes, but bracing the top of the shocks? There's just nothing there. Now, if someone can show me what force those braces work against, I'm all for 'em. But I just can't see it. Now, FL-SFCs, zomg that's a HUGE difference. Any fox-chassis car I own, that's the first mod.

YOU NEED TO READ THIS THEN. A strut bar, strut brace, or strut tower brace (STB) is a mostly aftermarket car suspension accessory usually used in conjunction with MacPherson struts on monocoque or unibody chassis to provide extra stiffness between the strut towers.

With a MacPherson strut suspension system where the spring and shock absorber are combined in the one suspension unit, the entire vertical suspension load is transmitted to the top of the vehicle's strut tower, unlike a double wishbone suspension where the spring and shock absorber may share the load separately. In general terms, a strut tower in a monocoque chassis is a reinforced portion of the inner wheel well and is not necessarily directly connected to the main chassis rails. For this reason there is inherent flex within the strut towers relative to the chassis rails.

A strut bar is designed to reduce this strut tower flex by tying two parallel strut towers together. This transmits the load of each strut tower during cornering which ties the two towers together and reduces chassis flex. To accomplish this effectively (especially on MacPherson strut suspensions), the bar must be rigid throughout its length, and also attached to the firewall.[citation needed]

[1SICK5.0VERT]

Originally Posted by 1SICK5.0VERT YOU NEED TO READ THIS THEN. A strut bar, strut brace, or strut tower brace (STB) is a mostly aftermarket car suspension accessory usually used in conjunction with MacPherson struts on monocoque or unibody chassis to provide extra stiffness between the strut towers. With a MacPherson strut suspension system where the spring and shock absorber are combined in the one suspension unit, the entire vertical suspension load is transmitted to the top of the vehicle's strut tower, unlike a double wishbone suspension where the spring and shock absorber may share the load separately. In general terms, a strut tower in a monocoque chassis is a reinforced portion of the inner wheel well and is not necessarily directly connected to the main chassis rails. For this reason there is inherent flex within the strut towers relative to the chassis rails. A strut bar is designed to reduce this strut tower flex by tying two parallel strut towers together. This transmits the load of each strut tower during cornering which ties the two towers together and reduces chassis flex. To accomplish this effectively (especially on MacPherson strut suspensions), the bar must be rigid throughout its length, and also attached to the firewall.[citation needed]

It is my belief that a strut bar definitely does help. And during the explanation that follows I will try to provide a convincing argument for this.
Figure 1 shows the forces of interest in a strut bar analysis. For this calculation only horizontal forces need be considered. There are of course vertical forces, but since the sum of forces must independently equal zero in both the horizontal and vertical directions, we can concentrate on just the horizontal forces in this analysis.




Figure 1


We must begin by making some assumptions. First, consider an M3 cornering such that it experiences 100% weight transfer at the front wheels. This is not at all unusual on a modified M3. We have probably all seen pictures of an M3 in a turn with its inside front wheel in the air. That is a sure sign of 100% weight transfer.


Second, let us assume that our M3 is cornering at 1G. Again, on a modified M3 with R-series tires, this is very plausible. If an M3 weighs 2700 lbs and has close to a 50/50 weight distribution, then the outside front tire must generate a lateral force of 1350 lbs under the circumstances just outlined.
Thus F1 = 1350 lbs as depicted in the figure above. The figure is really a "free body diagram" which considers the forces that act ON the strut/wheel assembly (the blue link in Figure 1). These forces must sum to zero in the horizontal direction. Also, the sum of the torque's acting on the strut/wheel assembly must cancel out. Our goal is to determine the force F3 which is the force that the strut tower exerts on the strut assembly. There is an equal and opposite force exerted on the strut tower BY the strut assembly.

We can solve for F3 if we do a balance of torque's around the outer ball joint (where the control arm attaches to the strut). What we get is:

F1(L2) = F3(L1) or, F3 = F1(L2/L1)

Now, we already know F1 = 1350 lbs. And we can determine L1 and L2 from a quick measurement of an M3 (L1 = 24.3" and L2 =6.0"). Thus F3 = 333lbs.

So the conclusion is that when an M3 corners at 1G with 100% weight transfer at the front wheels, there is a 333 lb force pulling OUT on the outer strut tower. Since the inside wheel is un-loaded there is no corresponding force generated at the inside strut tower. Therefore a strut tower bar tends to be in tension, not compression as is often believed.




Now we ask ourselves: How critical is a force of 333 lbs pulling on the outer strut tower?
This 333 lb load amounts to about 12% of the car's total weight. Even though the strut tower is designed mainly to manage vertical forces , 333 lbs in the horizontal direction is not going to permanently deform the chassis. But the problem is that this force is repeatedly applied over many cycles during the life of the car. The more you drive it hard the more cycles you generate. This can lead to fatigue failure of the material that forms the strut tower (or where the strut tower attaches to the inner fender well).

What a strut bar does is tie the two strut towers together so that they share the load applied at the outer tower. This gives you twice as much material to deal with the same cornering force and helps reduce fatigue stress in this area.

Another point to consider is that if your outer strut tower is deflected outwards 0.20" by this 333 lb force, then you just lost 0.5° of negative camber! If it deflects 0.42" you have lost a full degree of negative camber.

This demonstration has hopefully illustrated how a strut tower bar can be beneficial. But what about the possibility of a strut tower bar being under compression? This is examined on page 2 »



Contrary to the simplified analysis on the previous page, many people believe that a strut tower bar is predominantly under compression, not tension. This assertion is partially born out in some cars where the strut towers gradually move closer together over time. And I have heard of incidents where the strut tower bar was instrumented with strain gauges as the car was driven around. These tests show the strut tower bar is under compression as well as tension, depending on what the car is doing. One test showed that the highest loads recorded on the strut bar were in compression as the car was pulling out of a garage (sideways down an inclined driveway - we have all heard a stiff car twist under this condition).

So what is this all about? Is a strut tower bar under tension or compression? One likely theory is that it experiences both. It just depends on the driving conditions. Cornering on smooth asphalt induces tension. Driving in a straight line over bumps induces compression. A force diagram illustrating how compression forces result from driving in a straight line (over a bump) is shown in Figure 2:





Figure 2

The left side of the figure shows the resultant forces acting ON the strut tower assembly. Force 1 is the road holding the car up, and force 2 is the weight of the car. Forces 3 and 4 result to stop the strut from spinning (they counter the moment produced by forces 1 & 2). Force 4 of course has an opposite and equal reaction force which is Force 5. This is shown on the right (in green) and is the resulting compression force on the strut tower.

Bear in mind that when the car encounters a sharp bump or dip in the pavement that the chassis may momentarily experience 3 or 4 G's. This means that F1 and F2 in Figure 2 could equal about 2800 lbs! F3 and F4 (and therefore F5) are much smaller, but could still be quite significant. To calculate F5 more precisely requires some measurements. I will get to this eventually.

In conclusion, some cars spend most of their lives driving in a straight line. Such cars might experience the strut towers moving together over time. Track cars spend a lot of their time cornering at over 1G. Thus a track car might see it's strut towers spread apart over the years. Thus a strut tower bar can be under tension OR compression depending on the environment that the car is operated in.

[1SICK5.0VERT]

Originally Posted by 1sick5.0vert it is my belief that a strut bar definitely does help. And during the explanation that follows i will try to provide a convincing argument for this. Figure 1 shows the forces of interest in a strut bar analysis. For this calculation only horizontal forces need be considered. There are of course vertical forces, but since the sum of forces must independently equal zero in both the horizontal and vertical directions, we can concentrate on just the horizontal forces in this analysis. Figure 1 we must begin by making some assumptions. First, consider an m3 cornering such that it experiences 100% weight transfer at the front wheels. This is not at all unusual on a modified m3. We have probably all seen pictures of an m3 in a turn with its inside front wheel in the air. That is a sure sign of 100% weight transfer. Second, let us assume that our m3 is cornering at 1g. Again, on a modified m3 with r-series tires, this is very plausible. If an m3 weighs 2700 lbs and has close to a 50/50 weight distribution, then the outside front tire must generate a lateral force of 1350 lbs under the circumstances just outlined. Thus f1 = 1350 lbs as depicted in the figure above. The figure is really a "free body diagram" which considers the forces that act on the strut/wheel assembly (the blue link in figure 1). These forces must sum to zero in the horizontal direction. Also, the sum of the torque's acting on the strut/wheel assembly must cancel out. Our goal is to determine the force f3 which is the force that the strut tower exerts on the strut assembly. There is an equal and opposite force exerted on the strut tower by the strut assembly. We can solve for f3 if we do a balance of torque's around the outer ball joint (where the control arm attaches to the strut). What we get is: F1(l2) = f3(l1) or, f3 = f1(l2/l1) now, we already know f1 = 1350 lbs. And we can determine l1 and l2 from a quick measurement of an m3 (l1 = 24.3" and l2 =6.0"). Thus f3 = 333lbs. So the conclusion is that when an m3 corners at 1g with 100% weight transfer at the front wheels, there is a 333 lb force pulling out on the outer strut tower. Since the inside wheel is un-loaded there is no corresponding force generated at the inside strut tower. Therefore a strut tower bar tends to be in tension, not compression as is often believed. Now we ask ourselves: How critical is a force of 333 lbs pulling on the outer strut tower? This 333 lb load amounts to about 12% of the car's total weight. Even though the strut tower is designed mainly to manage vertical forces , 333 lbs in the horizontal direction is not going to permanently deform the chassis. But the problem is that this force is repeatedly applied over many cycles during the life of the car. The more you drive it hard the more cycles you generate. This can lead to fatigue failure of the material that forms the strut tower (or where the strut tower attaches to the inner fender well). What a strut bar does is tie the two strut towers together so that they share the load applied at the outer tower. This gives you twice as much material to deal with the same cornering force and helps reduce fatigue stress in this area. Another point to consider is that if your outer strut tower is deflected outwards 0.20" by this 333 lb force, then you just lost 0.5° of negative camber! If it deflects 0.42" you have lost a full degree of negative camber. This demonstration has hopefully illustrated how a strut tower bar can be beneficial. But what about the possibility of a strut tower bar being under compression? This is examined on page 2 » contrary to the simplified analysis on the previous page, many people believe that a strut tower bar is predominantly under compression, not tension. This assertion is partially born out in some cars where the strut towers gradually move closer together over time. And i have heard of incidents where the strut tower bar was instrumented with strain gauges as the car was driven around. These tests show the strut tower bar is under compression as well as tension, depending on what the car is doing. One test showed that the highest loads recorded on the strut bar were in compression as the car was pulling out of a garage (sideways down an inclined driveway - we have all heard a stiff car twist under this condition). So what is this all about? Is a strut tower bar under tension or compression? One likely theory is that it experiences both. It just depends on the driving conditions. Cornering on smooth asphalt induces tension. Driving in a straight line over bumps induces compression. A force diagram illustrating how compression forces result from driving in a straight line (over a bump) is shown in figure 2: Figure 2 the left side of the figure shows the resultant forces acting on the strut tower assembly. Force 1 is the road holding the car up, and force 2 is the weight of the car. Forces 3 and 4 result to stop the strut from spinning (they counter the moment produced by forces 1 & 2). Force 4 of course has an opposite and equal reaction force which is force 5. This is shown on the right (in green) and is the resulting compression force on the strut tower. Bear in mind that when the car encounters a sharp bump or dip in the pavement that the chassis may momentarily experience 3 or 4 g's. This means that f1 and f2 in figure 2 could equal about 2800 lbs! F3 and f4 (and therefore f5) are much smaller, but could still be quite significant. To calculate f5 more precisely requires some measurements. I will get to this eventually. In conclusion, some cars spend most of their lives driving in a straight line. Such cars might experience the strut towers moving together over time. Track cars spend a lot of their time cornering at over 1g. Thus a track car might see it's strut towers spread apart over the years. Thus a strut tower bar can be under tension or compression depending on the environment that the car is operated in.

sorry no pics

[ReverendDexter]

Do strut tower braces do ANYTHING? - Corner-Carvers Forums

[1SICK5.0VERT]

-- A few years back (in the early days of the Corral, no less) I got into it with a lurking Ford engineer on a couple of chassis issues, one of which was the value-added from the STB. This guy emailed me some loadpath summaries and project analyses as he was one of the folks in the group responsible. Turns out the STB from Ford was satisfactory in strengthening the cowl and strut towers by what would be a fairly decent amount on most respectable cars. This guy was pretty militant with the Ford beancounters for removing parts like these from the cars as the model line aged. He was even pissed about the clock-pod, or lack thereof, on the '98s. As militant as he was, he supported the notion that the STB did add rigidity and reduce flex.

Loading from the struts does cause the shock towers to deflect. As I stated before, there was a significant and easily noticeable improvement when I added my stb. I often leave the front brace off after working on the engine for test and tune sessions around the block. There is a noticeable difference with and without the front brace.

The unibody was never designed for the sorts of abuse we impose. The whole damn thing flexes and the shock towers are no exception. If you can't tell a difference with or without the stb, you need a better stb or your butt needs to be recalibrated. The fact that anyone can tell a difference indicates improvement is possible.