Because the upper control arm mounts and shock mounts are not radically loaded in a mopar, the shock tower braces is less about providing loading support than it is of increasing the rigidity of the simply cube structure that is the engine bay. By turning it into multiple smaller triangles, you can reduce the flex. Percentage of improvement by doing this, I can't quote a number.
Not sure how we define "radically" here. but with my back of the napkin thinking, since most all wheel forces transmit thru the front spindle, and the spindle being vertically approx 1/3 above the lower BJ, and the upper BJ approx 2/3 above the spindle, I think it would safe to assume the loads proportioned between the upper and lower as nearly the same ratio. And IMO, the K frame has much greater designed in robustness then the UCA mounting pivot points, beyond the above mentioned ratio, and the UCA apivot area would be an area next focused on, after the low hanging fruit upgrade of welding up the K member.
Seem to recall seeing somewhere that on a mopar the load is not equally split and the upper arm loads were a quarter to third of the lower arm loads. Could be recalling this incorrectly. If this is correct, they would not need as much reinforcement as the lower.
Because of the lack of loading in the upper parts of the engine bay, mounting a brace to the firewall can be effective in a mopar, but there is a question in my mind about putting structure that mounts in a large flat plane of sheet that doesn't make me think it is the most effective way to do it.
I always assumed two things on a well designed/installed
Monte Carlo brace on a Mopar, if achievable, both triangle braces from ea fender area would meet at a center node, and that node would also be on a seamed/flanged 90 degree joint of two metal OEM panels.
IMO, a basic monte carlo bar, or any of the other simple triangle braces being sold out there appear to be only marginally effective because they are bolting to stamped sheetmetal in tension without very large mountings plates to distribute the load. But if my point above this is valid, then they would not be supporting a significant load and may be okay after all.
I read a white paper on nascar design sometime ago. In it they stated that the most heavily loaded area is the firewall/a pillar area. While we aren't running out cars are near 200 mph speeds on superspeedways, it does seem logical to say that improvements in this area on a performance street car can yield gains as well, especially since we lack all the triangulation structure they have in this spot.
I wonder in the above if, "Heavily loaded" really means "loaded", or "highly stressed"?
Loaded vs stressed, entirely possible. I read this well over ten years ago, maybe even 20. Its been quite a long time. I'd imagine I've forgotten the finer details of it and in this case, those specifics do denote different factors.
