Rear strut brace designs..

[MusPuppis]

Going to be adding a rear strut brace before long and I came up with a couple designs. I'd like folks opinions on which one (if any) is decent.

 

 

Simple and straight forward. I would assume it would brace pretty well for most normal use (ie amatuer autocross stuff and generally driving like an ******* on occasion). ONe worry is cutting the stock angled braces to allow for the tubeing to pass through and be welded to the bottom of the tower. I dont know if this would weaken them. Perhaps they would need to be re-inforced?

 

 

This doesnt give alot of support if the lower area of the strut tower flexes, but it should brace it pretty well regardless I would think. The little black squares would be plates I would weld to the floor of the Z and the tubeing would then be welded onto the plates. The point being, it would be easier than cutting the current supports to allow for the tubing to pass through. A larger plate for the tube to mount to would disperse the forces applied a little more to wouldnt it? As opposed to it all being focused into one small area..

 

 

Same as the last one except the tube would be welded into the shock tower itself. Again brings up the question on wether or not cutting the stock braces to allow for the tube to pass through would weaken them.

 

 

Anyway, just some thoughts I had, I'd like folks opinions. I could be overthinking this as well of course and a simple, straight bar across the top would be all that was needed.. but *shrug*.

[Drax240z]

Scrap 1 all together.

 

Leave the existing braces in place. Do a top straight bar, and do your cross to the base of the existing braces.

[Phantom]

Look at rear strut brace in my album. Hoizontal bar on top with a single diagonal bar that comes from top and ties into lower part of existing brace on opposite side.

 

Variant of that would be a horizontal bar that has two diagonals that start at the center of the top horizontal bar and go out and down to the existing braces - it would look like a horizontal K.

[Drax240z]

The "K" shape will not be as rigid as a bar with an X in it, as the two lower bars will not be leading to a node, they will end in the center of a straight bar, transferring load somewhat perpendicular to the axis of the bar... consequently the direction of least strength. (and stiffness)

 

The best (easy) way to do this is something between the 2nd and 3rd pictures, leave the existing braces and end the X bar where they attach to the floor. This way the end of all your bars are on a node. Also try to attach the X bar to the horizontal bar at the same point that it attaches to the strut tower. A little more difficult to fabricate, but stiffer.

[Pop N Wood]

Is the X really necessary? Seems like the lower mounting point, where it goes into the side of the strut tower at the floor, would be so flexy that all the cross bars are adding is extra weight. I understand the desire to triangulate everything, but is the extra X really addressing a need or are people doing it because it l"ooks" like a good idea?

 

Plus I would think if bracing is needed, that you don't really need both parts of the X. Can't imagine needing more than a single bar going corner to corner.

 

Just asking.

[240Z2NV]

I essentially used "Phantom's" first version, and feel it worked out well and was simple and unobtrusive.

One bar horizontally attaching to welded-in tabs near the shock tower tops, then a diagonal bar from the top (just below the horizontal mount point) of one tower to the bottom of the opposite tower.

So, one shock tower has two sets of tabs holding the bars near the top, and the other tower has a pair of tabs at the top and a pair at the bottom.

Email me directly if you like, and I'll send a pic. Never learned how to post here....

[cyrus]

Analyze the forces. Since the strut move up and down with minimal side load the top bar is sufficient.

[Drax240z]

Many of your forces are horizontal side loading, in which case a top bar only creates a parallelogram - a shape that flexes readily.