Remove K Member '96 Cobra Convertible - Replace w/ MM Brace?

tcb-1 · Oct 20, 2014

Gang,

I posted over on the Facebook page, but thought I'd ask on the website as well.

I would like to remove the stock k member brace on my Cobra convertible. I'd like to go a bit lower on the front end, but the stock k member hangs down more than coupes. I know it is there for body stiffening so I want replace it with something that tucks up into the chassis a bit more.

Can I get you guys that have lowered convertibles to chime in? I was looking at the Maximum Motorsports k member brace. Had anyone replaced the entire stock brace in favor of the MM model?

Thanks for the help!!

95opal · Oct 20, 2014

stifflers kmember brace here

ttocs · Oct 20, 2014

95opal said:
stifflers kmember brace here

and a little extra.... I can't blame you for loving that pic it is a bit epic for an underside...

I was not aware of members that adjusted the ride height other then if you get A-arms that are adjustable. There are a few that move the motor forward/back but I don't remember seeing height adjustments.

Ferocious · Oct 20, 2014

Are you looking for something that actually improves stiffness or just something to replace it so you can go lower?

tcb-1 · Oct 20, 2014

Ferocious, trying to get lower, while maintaining the chassis stiffness, without destroying my ride. I know, I'm trying to have too many things. But the stock k brace hangs a good 2" below the lowest component. I know vert guys get lower than me, but I don't want to muck my car up in the quest of going lower.

Ferocious · Oct 20, 2014

I will be running a skid plate on mine in place of the x-brace soon enough. I'm not as concerned about chassis rigidity as I am about getting a hole in my oil pan. It's unconventional but it's the only option I have for my build. However, the x-brace should not be giving you any huge issues. I still have mine on the car (by some miracle) and I can still drive my car just fine. It hasn't been beaten to death just yet and mine hangs less than an inch from the ground.

95opal · Oct 20, 2014

ttocs said:
and a little extra.... I can't blame you for loving that pic it is a bit epic for an underside...

I was not aware of members that adjusted the ride height other then if you get A-arms that are adjustable. There are a few that move the motor forward/back but I don't remember seeing height adjustments.

Scott your a bit confused hes talking kmember brace not KMEMBER two different things. Verts came stock with the heavy ass x brace, aftermarket sells 4 boint two point lower braces

ttocs · Oct 21, 2014

OOOOOOOOOOOOOOOOOOOOOOOOOOOO

ReplicaR · Oct 21, 2014

95opal said:
stifflers kmember brace here

That just looks insane... and unnecessary. Trying to stop a twisting motion of the floor by bracing it with heim joints that are free to move around... That just doesn't make sense to me.

Sprayed Coupe · Oct 21, 2014

ReplicaR said:
That just looks insane... and unnecessary. Trying to stop a twisting motion of the floor by bracing it with heim joints that are free to move around... That just doesn't make sense to me.

The heim joints do nothing for twist, that's what the overkill subframe connectors are for. The linkages with the joints prevent the body from sag or bow front to rear. If that car is a vert all of that is getting put to good use.

95opal · Oct 22, 2014

ReplicaR said:
That just looks insane... and unnecessary. Trying to stop a twisting motion of the floor by bracing it with heim joints that are free to move around... That just doesn't make sense to me.

Sprayed Coupe said:
The heim joints do nothing for twist, that's what the overkill subframe connectors are for. The linkages with the joints prevent the body from sag or bow front to rear. If that car is a vert all of that is getting put to good use.

Lol gotta brush up on some new tech.
The system isnt for body twist. Too funny
Sprayed coupe yes its a vert and yes the front deflection is what they are designed to help with. They transfer the load to the subframe. Helps tremendously with braking and cornering, somthing i would think replicar would be into but apparently hes a little out of date with tech.

ReplicaR · Oct 22, 2014

95opal said:
Lol gotta brush up on some new tech.
The system isnt for body twist. Too funny
Sprayed coupe yes its a vert and yes the front deflection is what they are designed to help with. They transfer the load to the subframe. Helps tremendously with braking and cornering, somthing i would think replicar would be into but apparently hes a little out of date with tech.

My tech is just fine, thank you very much. I can see how it could possibly help with sag on a convertible, maybe braking (that's more due to your actual pads and tires), but cornering, I'm not so convinced. For corners you need solid mounted points, triangulation, and since the corner load is actually applied across the vehicle with load moving from front corner to opposite rear corner, I just don't see how all that bracing could possibly help. A proper way of doing cross chassis bracing is to have an actual X Brace. It's not an easy task with the live axle cars, since there is so much droop, and you don't want it to contact the driveshaft, and the exhaust clearance isn't great either. Best way of stiffening the chassis is a proper rollbar or cage.

95opal · Oct 22, 2014

ReplicaR said:
My tech is just fine, thank you very much. I can see how it could possibly help with sag on a convertible, maybe braking (that's more due to your actual pads and tires), but cornering, I'm not so convinced. For corners you need solid mounted points, triangulation, and since the corner load is actually applied across the vehicle with load moving from front corner to opposite rear corner, I just don't see how all that bracing could possibly help. A proper way of doing cross chassis bracing is to have an actual X Brace. It's not an easy task with the live axle cars, since there is so much droop, and you don't want it to contact the driveshaft, and the exhaust clearance isn't great either. Best way of stiffening the chassis is a proper rollbar or cage.

So because you cant understand how it works you want me to believe its unnecessary? Well im more inclinex to believe the guy who designed and tested the system being he is a former indycar engineer. But i supose your couple of laps around some cones and a bit of internet reading makes you more qualified in the field. Ive also spent a few hours with him talking about the setup and am quite confident it will do exactly what its intended for. BTW if you missed it im still working with a chassis guy pn a roll bar set up to top it off. I am taking no chances with this car and chassis flex as it is a vert and i do plan on putting down some serious hp so ill take every bit i can get. The next chassis set up you come out with let me know ill gladly try it out on another project.

ReplicaR · Oct 22, 2014

Lol personal attacks already? It's ok, I'm not going to get offended. I will say this though, that I don't really read the internet too much, mostly book when it comes to this subject. After I'm done reading those, I really try to visualize the concept behind the reading, so if I ever want to discuss it, I could actually see how it works in my head, and what goes on behind it. The following is my my opinion based on how I think this works:

I'm looking at that picture and here is what I'm noticing. I'm noticing that nothing is really solid mounted, which is supposed to help creates rigidity. I see that two one of the connections is being made to the transmission crossmember, which is mounted to the body with the use of polyurethane bushings, which are stiffer than rubber, but not really that solid, when you think about it. I also think that when the front corner (either side) will get loaded up under turning, the bracing that is mounted with heim joints will most likely let the corner move up, because heim joints allow for that free movement. Maybe due to all the tying together, it might create some sort of rigidity by limiting the movement, but in my option a much less complicated and most likely more effective way would have been to add an X-Brace tying the two corner together and triangulating it perfectly. I don't recall of the top my head, but I'm pretty sure 4 door M3 ran it that way on production cars, and so did some of the C4 Vettes (Grand Sport?). Just like the subframe connectors, a large area where the brace would connect and get welded in would allow for stiffer chassis as a result. As mentioned before, this is my opinion based on how I understand this subject.

95opal · Oct 22, 2014

So you consider pointing out the difference in chassis experience between you and a qualified engineer a personal attack. Lol im mearly trying to let you see how skewed your thinking is. First you say its unnecessary and cant see how it works. Then you go to saying it may possibly help braking. Then to your third round which i didnt bother to read because you seem to be set on coming up with anything to verify your first statement and im really not here to debate the product. Like i said im more than confident in its quality and design so whatever you come up with will be falling on deaf ears. If you followed my build you know i dont cut corners or waist money on useless crap that wont contribute to what im trying to acomplish with this car. If i did i would have slaped on some sub frame connectors like most everyone else and called it a day. Now ive been driving and modifying 5liter mustangs for about 27years now so when i finish this up i will give you a full detailed report on how the system works out. After all i should be able to decide by then if all that money and hours of welding mafe a difference. Until then ill have to agree to disagree with you on the unnecessary part.

ReplicaR · Oct 22, 2014

So, let's see... I offer some constructive criticism, and you can't take it, so you don't even read it, or care to respond? The main reason why I even changed my opinion, is because you've brought up something that I overlooked, and having said that, you did not even mention any reason why, just the selling points. Honestly, I don't follow your project for the same reason I don't follow anyone's projects. I just don't care, and don't have the time. Unless they benefit me directly. I've seen iRoush have some very interesting stuff, that one guy from FTR has some nice product. For anything more than that, I'll go elsewhere for Tech. I can fully understand that you have been at it for a while, but that doesn't do anything in terms of convincing me that the construction that you've got going on under your car is all that beneficial. If you can actually explain it further in detail, rather than say it helps because it helps, I would love to hear it. I'm never against learning something new, or seeing how someone's different take on the old concept.

95opal · Oct 23, 2014

ReplicaR said:
So, let's see... I offer some constructive criticism, and you can't take it, so you don't even read it, or care to respond? The main reason why I even changed my opinion, is because you've brought up something that I overlooked, and having said that, you did not even mention any reason why, just the selling points. Honestly, I don't follow your project for the same reason I don't follow anyone's projects. I just don't care, and don't have the time. Unless they benefit me directly. I've seen iRoush have some very interesting stuff, that one guy from FTR has some nice product. For anything more than that, I'll go elsewhere for Tech. I can fully understand that you have been at it for a while, but that doesn't do anything in terms of convincing me that the construction that you've got going on under your car is all that beneficial. If you can actually explain it further in detail, rather than say it helps because it helps, I would love to hear it. I'm never against learning something new, or seeing how someone's different take on the old concept.

Ok let me go all the way back to the beginning, the set up isnt for twist as im pretty sure that is how your thinking. As i stated earlier its for preventing the deflection of the front rails. You do realize the front rails move up and down on acceleration and stop correct. Now look at the bracing tied from the bottom of the kmember all the way back to the subframes. This transfers that load directly to the subframes helping eliminate that movement in turn helping braking and yes keeping correct alingnment during cornering. So if you really think about what it is designed to do you should without a doubt see that its going to do exactly what its intended for. Again if your still skeptical i will write a full review when i get it on the road.

ReplicaR · Oct 23, 2014

Ok, that makes sense to me. The whole reason why I brought up twisting to begin with is due to the way the chassis gets loaded in the corner. The outside front tire handles the most load, then it's split pretty evenly between the inside front and outside rear, and then the inside rear carries the least load during the cornering. So under these conditions the chassis benefits HUGELY from X-brace, because it squares and triangulates the corners of the car. I see that you've also mentioned something about alignment in the corner, so here is some food for thought. The lower control arms are connected to the K-member, which is connected to the front rail, that is connected to the strut tower. The bracing that you have on there would have little to no effect on corner load, because if the frame rail were to move, the strut tower and the k-member would go with it. I understand that maybe it would change in relation to the rest of the car, and we would have to be talking some extreme forces, but in relation to the road it remain the same, and therefore contact patch would not change.