RotorImp's S13 Fr Strut/Firewall Brace

[Peal]

Looking for opinions about this piece. Links the struts back to the firewall. Seems like a really nice design, but if so, why doesn't anyone else make them?

The guy makes a batch, then is unheard of for a few months so he's kind of hard to get ahold of in order to purchase them. I want one, and I don't really feel like paying someone to fab one up for me, so I've gotta wait.

Any opinions?

[KA240SX808]

Any pics w/ the Motor in? Looks like it might be close for a KA w/ new motor mounts

[Def]

I don't like only grabbing the strut tower over 1/3 of its area, plus the bends in the bar are going to make it not nearly as stiff as it could be in compression or tension across the strut towers.

It should really be a triangle, and it's pretty expensive for what it is IMO.

[Matt93SE]

Damn.. I typed a response several hours ago but it didn't post.. basically it echo's Def's opinion... The bends in the bar and the only support really being the center of a bow, that bar really isn't very stiff at all.

Ideally they should be straight tubes, one across the center, and two going from the strut tower to the firewall.. If you have a cage, there should also be another similar brace from the firewall to the dash tubes on the other side.

I certainly wouldn't pay much for that bar. horrible design.

[Def]

I think it's in the $120-150 range IIRC. People on NICO seem to nut themselves over it, equating heavy with stiffness. Not that I'm very surprised by that....

[Matt93SE]

There's a reason I quit going to and selling on NICO forums about 5 years ago.....

[Peal]

So paying someone to fab up something of a similar design but with a cross bar, maybe with something to allow preloading, to go from tower to tower.

[KA240SX808]

I read some where that putting a Dbl side threaded pipe (the ones that let you pre-load) in the middle would cause more flex in the Strut Bar.

[Def]

Not really, it's the hinged joints on the side that allow almost free rotation at each side.

That said, I don't know how much there is to gain in a strut bar by making the bar carry a bending moment. I imagine the small mounting area of most strut bars to the mounting plates would mean the actual resistance to any significant moment is very low. Plus I'm not sure there is going to be much significant distortion of the strut towers to put the strut bar in bending.

[Peal]

bending moment? Like a bolt or joint to put tension on the bar?

I've always heard that in older cars, especially those that are longer, the flex between strut towers is significant.

[Epstein]

I've always considered something like this as an add-on to a DC Sport bar of similar construction. Adding RotorImp's idea to a DC Sport bar looks like it would basically give you what DSG did, but in bolt-in form. The DC bar is made from steel, btw.

[Def]

bending moment? Like a bolt or joint to put tension on the bar?

I've always heard that in older cars, especially those that are longer, the flex between strut towers is significant.

A bending moment is what the bar would experience if you grabbed
one of the mounting plates and tried to twist it. A hinged bar lets this happen easier than a non-hinged one. Although I think the practical difference in stiffness between the two probably isn't huge.

[Peal]

Ok, so while we're at it, anyone want to make a short list of non-hinged solid strut bars?

An expensive solution to RotorImp's product may be to take his product and weld it to another steel bar with a larger attachment area.

[Bumnah]

I've been eye'n this guy:


Mainly for this added bling:


What say ye?

[Matt93SE]

Now you're talking.
Throw in some triangulated braces to the firewall and you're golden.