Shock tower braces
- Thread starter oilcan93
- Start date
my dear friend,
even if the front top strut is effectively creating torsion in the sheet metal of the front tower, because is rigidly bolted, (even though there is a rubber element to accomodate the forces), which is not the case in the rear one, if you read my comment, what i am saying is that lateral forces are present in both cases, because the shock is angled, i said not in the same way, that is clear
it os clear too that the strength of the rear structure is higher than that of the front one
Many of the structural issues in the E9 shell were addressed by the racing teams in the 70s and later. With the exception of the obvious benefits of a full roll cage there were many ways to strengthen this car.
Welding the doors shut would be best
+1Welding the doors shut would be best
duane_sword
Well-Known Member
I have front and rear strut braces
My coupe #4310155 has front and rear strut braces
The rear strut tower brace also serves as a convenient frame that houses the battery so there is more room up front (the bonnet or hood depending on your upbringing). In the case of my coupe the Alpina air-box plenum takes up a lot of real-estate so having the battery in the boot (or the trunk) is actually necessary… and I assume Alpina did it back in the day for some weight re-distribution also.
Front engine bay (no battery, front struts) and Rear trunk area with strut and battery.
My coupe #4310155 has front and rear strut braces
The rear strut tower brace also serves as a convenient frame that houses the battery so there is more room up front (the bonnet or hood depending on your upbringing). In the case of my coupe the Alpina air-box plenum takes up a lot of real-estate so having the battery in the boot (or the trunk) is actually necessary… and I assume Alpina did it back in the day for some weight re-distribution also.
Front engine bay (no battery, front struts) and Rear trunk area with strut and battery.
Attachments
Triangulating the rear should make a difference over simply tying them together. If only you could do that up front you would really stiffen things up.
IMO, moving the battery to the trunk is the biggest "one move" improvement you can make to handling in our cars.
IMO, moving the battery to the trunk is the biggest "one move" improvement you can make to handling in our cars.
Some are running these:
http://e9coupe.com/forum/showthread.php?t=4773
No idea if it helps, but it sure looks nice.
http://e9coupe.com/forum/showthread.php?t=4773
No idea if it helps, but it sure looks nice.
sreams
Well-Known Member
I guess all I'm saying is that flex at the front strut mount is going to change suspension geometry, while flex at the rear tower will only compress/extend the shock. The rear shock's angle is of little consequence, since it has no influence on the suspension geometry.
I do see the benefit for overall rigidity and for giving the battery a place to live.
-Scott
Duane who made your battery box/tower brace? ALso did you use the cable hardware from an E21?
duane_sword
Well-Known Member
Ireland Engineering
the original and prior owner to me for my coupe (VIN 4310155) secured the front and rear braces from Ireland Engineering… I would guess around 15+ years ago or more….
If NickD is on this forum perhaps he can shed more light on this topic for us.
http://www.iemotorsport.com/bmw/E9-E3-suspension-steering.html
the original and prior owner to me for my coupe (VIN 4310155) secured the front and rear braces from Ireland Engineering… I would guess around 15+ years ago or more….
If NickD is on this forum perhaps he can shed more light on this topic for us.
http://www.iemotorsport.com/bmw/E9-E3-suspension-steering.html
brea
Well-Known Member
E9 Front Strut bar on eBay
NMNA
http://www.ebay.com/itm/New-BMW-2-5CS-3-0CS-Front-Strut-Bar-Steel-E9-/261386290924
The one listed on eBay looks like the same ones you can get directly from Wallothnesh:
http://www.wallothnesch.com/catalog...store=eng&dir=desc&order=position_number&q=e9
NMNA
http://www.ebay.com/itm/New-BMW-2-5CS-3-0CS-Front-Strut-Bar-Steel-E9-/261386290924
The one listed on eBay looks like the same ones you can get directly from Wallothnesh:
http://www.wallothnesch.com/catalog...store=eng&dir=desc&order=position_number&q=e9
MPowerE9
Active Member
Korman Autoworks E9 Rear Strut Brace
Top End Performance E9 Coupe rear strut brace. (photo of the brace on a 2002)
Both products looks nearly identical.
Top End Performance E9 Coupe rear strut brace. (photo of the brace on a 2002)
Both products looks nearly identical.
Nick Daffern
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Duane,
I bought the front strut brace from Richard Conway maybe 20 years ago when he made up a limited run of them. Sorry, I just don't remember where I got the rear brace. I always intended to install them but just never got around to doing it. Glad you did.
Enjoy the driving season. I finally get the Speedster back from the LeMay Museum at the end of May...they extended the exhibit...looking forward to driving it.
Cheers mate.
I bought the front strut brace from Richard Conway maybe 20 years ago when he made up a limited run of them. Sorry, I just don't remember where I got the rear brace. I always intended to install them but just never got around to doing it. Glad you did.
Enjoy the driving season. I finally get the Speedster back from the LeMay Museum at the end of May...they extended the exhibit...looking forward to driving it.
Cheers mate.
The rear is an area where there appears to be a fair amount of torque reaction in the chassis via the differential. I'm hoping I'm right with my observations that this area can be triangulated via the battery holder / cross brace tied to a 3mm trunk mounted floor plate which is in turn through bolted to a 3mm plate reinforcing box welded to the diff housing which is in turn welded to a 3mm strengthening plate welded to the chassis cross member. Looks complicated but it's pretty simple really and, apart from the battery holder, quite discreet.
I've also done extensive stitch welding in the engine bay, suspension towers, dash area, floor pan, trans' tunnel, firewall, footwells, front seat frames, the panel that runs across the floor behind the front seats, all around the rear seat area, suspension mount points front and rear, trunk, roof pillars and myriad other places not worth recounting plus reinforcement brackets in the engine bay from the chassis rails to the firewall, small triangulation brackets in various places etc. Okay, the car will never be as solid as a Sherman but hopefully this work will go a long way to achieving some stiffness. And yes the fact remains that there is a gaping hole from one side of the car to the other and it has pencil thin roof pillars and it was assembled using doubtful at best quality control. All of that only makes me want to do as much as I can to help the old girl.
Much of this info is available on the Coupeking site plus additional research on the CSL race teams and what passes for,for me anyway, obvious things to do.
I've also done extensive stitch welding in the engine bay, suspension towers, dash area, floor pan, trans' tunnel, firewall, footwells, front seat frames, the panel that runs across the floor behind the front seats, all around the rear seat area, suspension mount points front and rear, trunk, roof pillars and myriad other places not worth recounting plus reinforcement brackets in the engine bay from the chassis rails to the firewall, small triangulation brackets in various places etc. Okay, the car will never be as solid as a Sherman but hopefully this work will go a long way to achieving some stiffness. And yes the fact remains that there is a gaping hole from one side of the car to the other and it has pencil thin roof pillars and it was assembled using doubtful at best quality control. All of that only makes me want to do as much as I can to help the old girl.
Much of this info is available on the Coupeking site plus additional research on the CSL race teams and what passes for,for me anyway, obvious things to do.
Nick Daffern
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The E9 chassis is pretty flexible as anyone who has jacked up one side of the car knows; the front and rear braces help relatively little. Looking at pictures of the race Coupes will show they tied all 4 corners together with a full cage. To be honest though, the vast majority of us wouldn't know the difference on the street. My Coupe handled pretty darned well with the Alpina package, bearing in mind that it was a relatively heavy car, but it had its limitations.
For the real world I'd be more concerned with the rear strut towers failing over time with the use of uprated springs and harder shocks, and the rear brace helps with that.
For the real world I'd be more concerned with the rear strut towers failing over time with the use of uprated springs and harder shocks, and the rear brace helps with that.
'69 2800cs
Well-Known Member
<<<For the real world I'd be more concerned with the rear strut towers failing over time with the use of uprated springs and harder shocks, and the rear brace helps with that.>>>
Sorry, this is not correct. First, the rear towers are *shock towers*, and the front are *strut towers*. Shocks and struts and two different things, and that's why bracing strut towers makes a lot of sense and bracing shock towers a lot less so.
Second, the rear springs don't contact the shock tower, so stiff springs will have no effect on them. And, stiff shocks in the rear create vertical loads on that sheetmetal. Bracing it from the side will have little effect. The failure mode I've seen for rear shock towers is the sheet metal at the top fails, something the rear brace can't help with anyway.
I think the rear shock brace is cool, and I like the battery holder idea too. Heck, I may put one on my car someday, but the benefit is it will only sort of vaguely stiffen a small part of the rear of the car.
A front strut brace on the other hand helps maintain wheel alignment under hard cornering and that has measurable performance benefits.
Sorry, this is not correct. First, the rear towers are *shock towers*, and the front are *strut towers*. Shocks and struts and two different things, and that's why bracing strut towers makes a lot of sense and bracing shock towers a lot less so.
Second, the rear springs don't contact the shock tower, so stiff springs will have no effect on them. And, stiff shocks in the rear create vertical loads on that sheetmetal. Bracing it from the side will have little effect. The failure mode I've seen for rear shock towers is the sheet metal at the top fails, something the rear brace can't help with anyway.
I think the rear shock brace is cool, and I like the battery holder idea too. Heck, I may put one on my car someday, but the benefit is it will only sort of vaguely stiffen a small part of the rear of the car.
A front strut brace on the other hand helps maintain wheel alignment under hard cornering and that has measurable performance benefits.
Nick Daffern
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69 2800cs...gee, thanks for schooling me. The rear "shock" towers do fail over time due to stiff settings on shocks like Koni's. I've seen it happen. The rear strut brace that goes over the top of the tower does reinforce the area although the real fix is to weld in a cap or a new tower if it's too far gone.