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Ultimate Front Strut Brace F/S


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Very cool design! I do have one question for those in the know:

 

What in the blazes are the jointed ends (Heim, etc.) for in a strut bar? I though the idea was to 'box' the compartment, and therefore MINIMAL/NO movement was the idea. Is my assumption incorrect???? Set me straight here, guys! cry2.gif

 

Davy

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there are jointed ends-at the strut towers. they appear to be for removal only. material looks like chromoly [sp?]. looking at the points [4] where it attaches to the firewall, i'm curious as to what support he put behind those mounting points-or if it would be necessary? anyone?

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I welded a 1/8" steel plate that was 1.5" x 6" in the center of the firewall at the top. Before I welded it to the firewall, I welded 3 flange nuts on the back side, over holes drilled in the plate (the brace bracket then bolts onto the plate via bolts that screw into the flange nuts on the back side). I was a little worried that any flexing would cause it to rip or crack eventually, which is why I went with such a large plate to distribute the loading. It has never shown any weakness yet.

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Looking at the pictures I see that the car is a 71Z. The fact that it is a 71 is not so important. What interest me is the front bar that goes down to the sub frame. Its anchor point looks to be on top of where the sway bar goes. However there is no sway bar on this Z. I have had the 1" bar that I use rip the subframe to pieces at this point. On the 71 I now have I put a plate on top of the frame and used long threaded bolts for the sway bar with nuts on top. I would think that this front bar if welded on the top end would stiffen this up. It looks like this setup has a slip fit on top and if there was any movement there would be another squeek or rattle from this area.

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Originally posted by Dave:

I have had the 1" bar that I use rip the subframe to pieces at this point. On the 71 I now have I put a plate on top of the frame and used long threaded bolts for the sway bar with nuts on top. I would think that this front bar if welded on the top end would stiffen this up.

I've seen the same thing. We do exactly what you did on our ITS race cars. On the EP cars where the rules give us a little more leeway, we have the plate you mention extend up into the inner fender panel to smear the loads out some more. This strut bar looks like it tries to help with that, which is meritorious.
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okay some clarifications for your questions:

 

The 4 ends mount to the firewall behind the firewall are factory braces that distribute any stress to the rest of the chassis, if you remove the cowl you can clearly see the factory bracing.

 

the swaybar mount goes THROUGH the frame rail, my car experienced frame rail cracking from too large of a sway bar, you can see the repair in one of the photos.The sway bar has been removed so the bottom plate can be seen. I have added photos that will clarify this. see the newly added photos. and forward any questions to PDK Racing or Me at rcarter@iwaynetworks.com for a faster response..

 

Ron

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Guest Anonymous

Why all the complexity? I have never seen a strut bar like that on any unibody car. Seems to me a simple triangulated bar (Top End) would suffice.

 

Why the down tubes to the frame? I think that you would lose very little without them?

 

If you have a structual diagram with all the X,Y,Z stress factors, I would like to get a gander at it. smile.gif

 

Mike

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Guest Anonymous

i got the top end performance strut bar for my 73 240Z did anyone else have trouble putting it in? it didnt fit right, i had to force it into the firewall (bending the firewall) and it barely fit over the little circular dish thingy on the strut tower.

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Guest Anonymous

I have heard of some guys having trouble fitting the TEP bar. The general conclusion is that your car is a bit twisted and the TEP bar needs to force the chassis back into alignment.

 

Mike

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Every car at the MSA show that had similar bracing in the engine bay was done wrong.

 

The bars from the firewall to the struts were all just attached to the firewall with some plate steel reinforcement. They were all placed way too far inboard. (near the hood latch) There is no suport there..just some sheet metal...and your wiper motors.

 

I too have some plate steel reinforcement, but as someone mentioned above, if you remove the cowel, you can see two pieces of bracing behind the firewall that give the firewall "fore and aft" support. This is where you want to mount those braces. They can be found in the area of the cowel that has no vent slots in it.

 

Many people use Heim joints to mount these things. What it does do, is give you the ability to adjust or preload the bracing... in a race car, you may want or have to have proper roll cage diameter tubes in there, as part of the "cage".. in that case you don't want them to move..ever.

 

In my application, I use heim joints in my engine bay, so I can have easy access to my engine, and for removal purposes. I could not fit my tower brace bar back in after my engine swap because of clearance. So I have a giant "X" that goes from the towers to the front rad support. Those mounts have plate reinforcement, and the top and bottom rad support are tied to these by square tubular steel that join the left and right sides of the rad support together. No more flex. All are adjustable except the top and bottom rad supports which are permenantly welded in place, Which happen to be nice mounting points for my I/C

HEHE

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Originally posted by ZR8ED:

The bars from the firewall to the struts were all just attached to the firewall with some plate steel reinforcement. They were all placed way too far inboard. (near the hood latch) There is no suport there..just some sheet metal...and your wiper motors.

Actually, if the two bars from the struts met at the same point in the center of the firewall, say behind the hood latch, torsion and side loads from the front of the chassis result in tension in one bar and compression in the other, which cancels out in the fore/aft direction and results in only lateral loads at the attachment, so it ain't an issue if done properly. It is an issue when the two bars don't meet at a point.
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SHOCK96,

 

sorry no diagrams available, but think of it this way: all of the twisting of the chassis is the effect of two locations in working in oposite directions...the front suspension (as it loads up going around a turn)and the sway bar which is working against the front suspension to keep the chassis level...over time these forces will tear the frame rail or strip the bolt inserts for the sway bar...by tieing the strut tower and the sway bar link together we eliminate the stress to the frame rail by coupling these units together...All you have to do is look at older datsun race cars where oversized swaybars have destroyed the front frame rails and ripped apart radiators....

 

I hope this helps...

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