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custom strut bars


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Dave Greimann made these tower braces from some pretty humble parts. Not much money either but look very clean and professional.

 

If you do a search for his name and then click the link to his page you can learn more.

 

Approach looks familiar :) I'm quite certain Dave did his prior to me doing mine' date=' quite similar. We're both missing the key lateral one but the ones shown do help as well.

 

[img']http://www.modern-motorsports.com/miscpics/mycar/P8190002.jpg[/img]

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I have looked at your setups and have only one question: WHY??????????

installing an adjustable bar that way on a zx or any z for that matter does very little.

I have personally taken the time to look at the structural improvements of such an install and have determined it to be a waste of money. The metal on the cowl is to thin, and the position of the bar to the side of the strut tower is to thin to make it worth anything.

If you want some real stregnth, then do this.

First off mount the bar to the strut bolts on top of the tower, then install a bar flat stock C channel would be very nice across the front of the cowl of the engine compartment. That will give you some strength.

installing an adjustable bar on the hood latch is a total waste of time, the metal there is so thin it will not provide any stress relief or securing of the tower to ant significant amount to make it worth the effort.

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I don't have a pic of the one I've fabricated, but I have adjusted it and you can adjust it and see the towers flex. Not sure on the ZX, but on the Z the supports ti the cowl is pretty sturdy, but the whole shell of the Z isn't exactly thick metal in the 1st place. However, Fabricating those braces didn't cost a lot (I hope) since there is about $100 worth of parts in both braces... If nothing else, they look cool! 8)

 

Mike

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Here are a couple of pics of the one I whipped up. I was in a bit of a bind as I had cut off my hood latch from the firewall when I had planned on using a rear distributor V8, so I needed to somehow mount something without messing up the painted firewall. Here is what I did:

 

f9c31698.jpg

 

f9c31154.jpg

 

The mounting points at the firewall are right next to the reinforcements under the cowl, and is attached to both the firewall and the reinforcement sheetmetal.

 

Tim

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I have looked at your setups and have only one question: WHY??????????

installing an adjustable bar that way on a zx or any z for that matter does very little.

I have personally taken the time to look at the structural improvements of such an install and have determined it to be a waste of money. The metal on the cowl is to thin' date=' and the position of the bar to the side of the strut tower is to thin to make it worth anything.

If you want some real stregnth, then do this.

First off mount the bar to the strut bolts on top of the tower, then install a bar flat stock C channel would be very nice across the front of the cowl of the engine compartment. That will give you some strength.

installing an adjustable bar on the hood latch is a total waste of time, the metal there is so thin it will not provide any stress relief or securing of the tower to ant significant amount to make it worth the effort.[/quote']

 

Pretty blanket statements/summations you tossed out Jeff all of which I disagree except that your suggestion is stronger (and not sure who has something on the hood latch)?? We took the time to look into it, prove it out, do it and subsequently enjoy it for years now, I don't factually understand your negative assertions. Mine's been daily driven hard/tracked/autoxed etc. The ZX cowl is very strong as is the Z, and they accomplishes a lot in their unibody function. Sure your description is stronger, but you don't need a 10lb piece to do a 1 lb job. I'm glad you saved your dough, but we enjoyed our setups and yes, they served our functional purpose just fine. Your setup as described works fine, but so does my own.

 

FWIW, those doing a cheap front strut bar, easiest way is to take a section of lightweight thinwall small OD (ie. 5/8's) tubing, flatten the ends, drill holes for your strut tower bolts, and fasten. This 15 minute job can make a fine difference.

 

Respectfully,

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There have been thread on this before. This is one of the areas on a Z car that is prone to flexing according to John Coffey and others. A bit more bracing then factory is a good thing, especially those cars that are driven hard.

 

Davy

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I have personally taken the time to look at the structural improvements of such an install and have determined it to be a waste of money. The metal on the cowl is to thin, and the position of the bar to the side of the strut tower is to thin to make it worth anything.

 

I can't speak for the ZX, but a setup like Dave's does work very well on a 240Z if you keep in mind a couple things.

 

First, the strut towers twist when lateral loads are applied. This twist is counterclockwise (from above) for the right and clockwise for the left towers.

 

Second, the cowl area of a 240Z is basically shaped like a triangle with the base at the firewall. The two legs of the triangle are the top of the cowl and the bottom, as indicated by the line of spot welds across the firewall about 5" down from the top.

 

Third, if you vertically span the base of this triangle in the center of the firewall, connecting the legs with, say, a 6" tall, 4" wide, .065" thick plate of 4130 you've created a pretty strong mount with the loads transferred to the cowl area through the two triangle legs. More then strong enough to counter the remaing loads that are causing the towers to twist.

 

Fourth, mounting a similar plate on the sides of the strut towers give you additional leverage over the twisting motion.

 

Fifth, connecting the sides of the strut towers to the center mounting area puts those loads into the braces as compression loads, which a straight tube is very good at resisting.

 

So, with some thought and design that type of strut tower bracing is effective, simple, and lightweight.

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I guess the first thing I need to clarify would be the application of the bars and their relative location. The other thing theat needs to be realixed is the hp and torque of the engine installed in the car.

I ran my car for a long time without a strut bar and I was running a good amount of torque and hp. The biggest problem I had with the car was the suspension and its components of the car rather then body flex.

The strut rods were a big improvement, and the control arm bushings as well. I noticed more improvement then from just about anything else I did with the front, and a good 1 1/8" sway bar and good shocks and springs. Those upgrades did more for the car then a top strut tower brace will ever do for the car.

if you go to the side of the tower(at least on my car) and press the side of the tower say 4" down on the tower, you can see the metal flex as you push on it, not very strong, it will flex, and dent with any significant force applied to it. The cowl is seemingly stronger, but tap it with a hammer and you will dent it easily. So that is the reason for my comments.

Really if you want to REALLY strengthen the chassis of the car, then build an engine plate, attach brackets to the cross member bolts, attach a bar to the plate from the strut tower TOP. Then you have the foundation to link the front to the rear. That setup is really strong and will stop body flex.

I agree, adding the bars do look good, but a bar to the radiator support will only support the radiator, not a big issue there with flex.

I dont know, I'm not trying to be critical or rain on someones party, but I figure if I am going to go to that extent with the car, I may as well do a complete job, and make it fully functional for my time effort and money.

anyway, sorry if I offended anyone. :D

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  • 8 years later...

I am planning on connecting the rear strut towers in my 71 240z. Is it better to bolt it to the top of the struts? or can I just weld bars between the diagonal braces between the towers?

 

If a bolt connection is better, I will place one bar between the tops of the towers, and build a simple truss in between the towers.

 

One issue is - If I use the bolt connection at the top, is there any use of it being removable, since the rest would be welded?

 

FYI,I would use 1/2" x 1" steel bars. Im not overly concerned about weight.

post-29918-0-24897500-1357450596_thumb.jpg

post-29918-0-01424100-1357450609_thumb.jpg

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I carry race tires in my trunk/hatch. And a hydraulic floor jack. And a helmet. And a folding chair. And a small tool kit. And an umbrella. And a fire extinguisher. I couldn't do that with a strut brace. And I feel naked without my fire extinguisher-I know too well the guy who built my car.

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I carry race tires in my trunk/hatch. And a hydraulic floor jack. And a helmet. And a folding chair. And a small tool kit. And an umbrella. And a fire extinguisher. I couldn't do that with a strut brace.

 

How about a bolt in strut brace, leave the mounts attached to the tops of the shock towers and just take the cross bar out to carry all you stuff, take your stuff out at the track and bolt the cross bar back to the mounts?

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The cool thing is you can do anything you desire; just my experiences.  I'm going thru the same "what if" thought process on roll bars.  I would definitely do a bolt-on so you can change your mind.  I really don't think that most of us need a strut bar on either end, but they look cool so we do them.  My engine is in the way for one in front.  I really only want a roll cage so that I can get my car certified for drag racing-you really only "need" a roll cage once.

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  • 1 month later...

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