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Addressing firewall flex


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#21 heavy85

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Posted 23 December 2016 - 11:34 PM

Strut tower braces to the firewall might do the trick.


No, the deflection is local to where the pedals mount which is too far from a typical strut tower brace. Also in that first pic I can't imagine why one would want to add the cost / complexity / and undesired degrees of freedom by putting rod ends on the two legs to the firewall. There are also lighter, more compact solutions to the firewall flex under the brake pedal but that requires modding the pedal box which is a decent amount of work to get to removing the dash etc.

Edited by heavy85, 25 December 2016 - 10:16 PM.


#22 grannyknot

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Posted 24 December 2016 - 05:16 AM

I see what you mean yes, but i was thinking more up/down side/side motions from the strut tower itself flexing in compairson to the position to the MC under hard cornering and big bumps. Just seems to be there would still be other flex and stress forces that could cause rubbing in a chassis as flexy as these cars are.

 

 

Strut tower braces to the firewall might do the trick.

 

I noticed that going from a 240Z booster to a 280Z booster reduced firewall flex somewhat.

I agree so I hope I have addressed that with theses braces,

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#23 Evlevo

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Posted 24 December 2016 - 05:34 AM

I agree so I hope I have addressed that with theses braces,

attachicon.gifDSCN0803.JPGattachicon.gifDSCN0861.JPGattachicon.gifDSCN0859.JPG

 

 

I think that should do the trick!



#24 TUME

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Posted 24 December 2016 - 07:36 PM

I`m afraid, those does´t help with firewall flexing.  Here is my solution, didn´t think firewall when did this but maybe helps a bit with it.

Attached Files


RS13 & HLS30 + A33  Arttu @ dnsf.org


#25 Miles

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Posted 24 December 2016 - 08:39 PM

I`m afraid, those does´t help with firewall flexing.  Here is my solution, didn´t think firewall when did this but maybe helps a bit with it.

 

Not for firewall flex. For strut tower movement. Anything attached to the strut tower (such as a device to arrest master cylinder movement) will also move.


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#26 Evlevo

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Posted 25 December 2016 - 07:04 PM

Not for firewall flex. For strut tower movement. Anything attached to the strut tower (such as a device to arrest master cylinder movement) will also move.

 

 

That's exactly what i was getting at. If your towers are flapping in the wind, so would anything attached to them. Locking down any chassis flex would fix this issue.



#27 TUME

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Posted 26 December 2016 - 03:15 AM

Those pipes from strut towers goes through firewall and are attached to roll cage. 

Attached Files


RS13 & HLS30 + A33  Arttu @ dnsf.org


#28 grannyknot

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Posted 26 December 2016 - 04:57 AM

Guys, while I'm sure a full, welded in roll cage/sub structure will stiffen the car, I'm just trying to find a firmer bake pedal.

By backing up the firewall with support from the shock tower I'm pretty sure that will be enough to give a better feel to the brakes.    What this mod is really trying to do is eliminate in a cost and weight effective way one of the many variables when changing the various brake components.



#29 RebekahsZ

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Posted 26 December 2016 - 12:40 PM

Your solution is fine. Most of the time a little firewall flex is tolerable and most folks don't know if their car has any or not. The symptom I was having was insufficient clutch master cylinder stroke (because the firewall was moving away from my foot about 1/4 inch) and my push rod was just barely long enough. My support rods from the firewall to the inner fender fixed my poor disengagement problem. But the real problem was that my clutch push rod was too short. When I lengthened that, the problem of insufficient stroke was REALLY fixed, and I'm pretty sure that my clutch would have disengaged better and the firewall reinforcement might not have been necessary. Be confident in yourself. Lots of folks think that their way is the ONLY way. But whatever works is ok by me, and your car. If one thing doesn't work, keep at it til you win.

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