Bosko

I just put the Street & Track strut rods on my 1971. I have not had it on the road yet, so no guidance on how they perform. Like Buckeye above, I made lots of changes at once, so I will not have any idea how the individual mods work.

A question to the OP - I see you cross drilled your frame rail to mount the hiem joint, instead of using the factory mount location. I thought about doing this on mine, since it would make it easier to create my own strut rod design and install it. I did not go down that path because I was worried about the structural loads in the frame. Instead of the loads reacting through the plate and across the entire depth of the frame, they will now be concentrated around the hole. i do not know if that is really an issue, but it seems that you would want to at least weld in a reinforcing plate to thicken the sides of the frame rails to better distribute the loads. Do you have any concerns about deformation of the frame rail or cracks forming as a result of changing the mounting location and method?

This is not meant as a criticism, I'm just looking for some education. :-)

clittleton07

The strut rod does clear everything. I do not know anything about retreating the chromolly after welding; the local raceshop I went to, to source the materials, said they just tig it and there is no extra prep. Where i drilled the hole for the front heim was doubled walled frame rail so there is plenty of strength there I dont think there will be any chance of a stress crack forming. The car still rides great, not harsh at all. I am by no means an expert on mustang suspension but this mod does work great for my car. Thanks for the feedback guys.
Chris

Old Mustanger

The problem is that the Lower Control Arm on these Mustangs is pretty weak. It is stiffened significantly by the 2 attachment points of the Strut Bar and by the Strut Bar itself.

If you had kept a similar attachment method on the LCA I am sure that you would be golden. But your design adds another pivot point an inch or so above the LCA, this significantly weakens the LCA.

I am pretty certain that under hard braking and especially when braking and hitting bumps at the same time that the LCA will twist on it's axis and fail. Iv'e had one of these suspensions fail at speed and I rolled the car, I don't recommend it.

Remove the rear heim joint & replace it with a 2-bolt attachment plane and you will be stiffer & stronger than stock.

clittleton07

The mounts are bolted in the stock strut rod location. I actually reused the existing holes and bolts for my mount. I more or less copied my design from a 67 mustang that has been high 7s in the quarter. The only difference is that I bolted my mount and he welded his directly to the LCA. This works fine for him and it has so far worked fine for me. Thanks again for the feed back though sir.
Chris

groho

Chris, those welds looked amazing! Old stanger mentions the LCA as a weak point. Wouldn't it make sense to strengthen the LCA by boxing it with a plate across the bottom. It's common to box frames and parts to build strength, so why not the LCA?

clittleton07

I may box the LCAs in. I just have to make sure that I leave enough room to get to the nuts on the bottom of the bolts holding on the stut rod mount.

OCHOHILL

More less copied??? What was the other design and how does yours differ?

Going fast isn't the problem, it's when you step on the brakes that is the problem. When the brakes are applied the lower ball joint is forced to the rear of the vehicle. Your rear strut mount allows that to rotate about the length of the arm. It will bind the inner joint until it fails from the twist and moving rearward. It is not a question of if but when. If you changed your design to include a heim at the inner LCA, what happens? Your LCA is on 3 pivot points and nothing is solid.

I thought I was pretty smart when I came up with this on my own(see link), only to find that Cobra Automotive came up with it some time before. If I didn't care about you or those around you I wouldn't say a thing. Don't take offense to the advice.

http://forums.vintage-mustang.com/mo...trut-rods.html

This has been on the car since the date posted and thus far tolerates abuse from my 17 yr old (wilwood discs on front, with 235 tires)

clittleton07

The only difference between mine and the one I mentioned that I copied were that his brackets were welded on and mine are bolted on. I dont see this causing extra stress on the arm. The strut rod is just intended to keep the LCA from moving foward and backwards. I can see what your saying but I do believe its irrelevant. This design has proved itself in a car that will see much worse than mine ever will. Thank you for the feedback though.
Chris

JMD

I opened this post a while back looked it over and then closed it. I opened it back up tonight wanting to see what the "naysayers" might be mentioning about this mod.

Well funny thing is, I kind of agree with the naysayers. The design WILL cause the LCA to twist more than stock, because the strut will no longer add torsional stability to prevent the LCA from twisting, furthermore this is going to be made worse because the bolt on mount raises the mount point as to put more leverage into the twist that the strut will induce.

In short, the stock design lends support to the LCA, this design will also induce twist.

I think the basic idea is good, the workmanship is great, but the fundamental change in structure is a little too scary for me to take the risk without updating the LCA.

The question is whether this induced twist is beyond the functional limits of the LCA.

OCHOHILL

Many don't realize the LCA and strut rod bolted together make a rudimentary 'A' arm.

I am not saying this is OK but in theory, if you lined up(made linear) the 3 points (inner joint, outer ball joint and the rear strut heim) you could use a double heimed strut rod since the stress is in braking and would put the rod in tension without inducing twist.

With any luck Mr. Peterson may add to the thread, although I haven't seen him post here in a while.