seam welding and rear suspension strengthening, What to do, What I did... Options

[Andyrew]

Thanks Chris!

I'll do that.. looks strong to me.

What guage metal did you use?

[ChrisFoley]

I have one set of these parts in stock.
Add a tubular brace from the inner console to the firewall and you won't ever have cracking problems with the rear suspension pickups.

[Andyrew]

Checked your site, Didnt see a price.

I dont have oogles of bucks... lots more things to buy ( my list of things to buy takes me to a -3000 left in the bank (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) )

Whats your price?

I know your very knowlegable when it comes to this, what do you think about my plan there? Not a whole lot of metal added.. less than the GT kit.. 2 tubes (one like you said, and one behind it.. locking in the ear)

Im worried because im currently at 275lb springs, will be running true slicks sometime in the future (10's and 11's) and I dont want to go with a cage because I will drive it on the street.



Andrew

[ChrisFoley]

Cracking in this area is primarily due to repeated flexing of the panels which loosens up the pinch welds and/or starts cracks at highly stressed areas of panels. I think what I designed eliminates the flex issue by spreading the loads out to otherwise unstressed areas, therefore stops cracking and spot weld loosening.
I've never been a big fan of seam welds. While it tightens things up it also causes shrinkage/warpage. I like to design things that minimize the total amount of welding required, and use the least amount of added metal to accomplish the goal.
Note the additional 14ga. piece along the rocker in front of the outer console. It isn't essential but provides reinforcement to the area between the console and the jack post. I think the GT kits had a similar piece in that location.
Regarding the tubular reinforcement of the inner console, I don't think the rearward tube is nearly as valuable as the forward one since the highest loads are on the outer wheel in cornering and the forces push the console in and up. The upward force is well resisted by the existing structure IMO.
Here's an example of the tubular brace I like.

[Jeroen]

Andyrew,
The blue tube in your sketch won't do anything
The part you are connecting it to isn't structural...

another area to put some thought in is were the framerail ends at the rear shock mount
with the firewall in place it's gonna be hard to weld the vertical part of it, but you can seem weld the top/horizontal part of framerail to the firewall and on the other side of the firewall, seem weld the shock tower

stichwelding the rest of the shock tower isn't a bad idea either

check brant's build thread, you'll find some good pics there (including how he managed to weld the vertical part of the framerail by cutting a section out of the firewall)

re: the rear susp bolts coming loose
maybe your the shoulders of your bushings are are too "high"
the trailing arm shaft should be slightly wider than the bushings to get a secure mount

[Andyrew]

Thanks Chris,

That helps!

That is exactly what I was going to do for the bar up front.

[jonwatts]

QUOTE (Jeroen @ Mar 22 2006, 06:07 PM)

Andyrew, The blue tube in your sketch won't do anything The part you are connecting it to isn't structural...

Aww ya beat me to it.

[Andyrew]

Jeroen, Sorry didnt see your post...

I didnt know if that piece was structural or not, but I figured seam welding things to it would help it be used as a pivot point..

I will stitch weld the whole shock tower, is there any portion that would benifit from adding metal to it? I have 275 lb springs, I remember brad saying the max he's used without having problems was 250, so i figure stitch welding the rest of the are would help.

The welding the vertical part of the framewell, are you refering to were the shock tower meets the longitudnal? I was planning on welding it, I will check Brants build and save any pictures I see of chassis stiffening.


I have new bushings for the rear arm, I do not know if they have been done before on this arm. I have another set of arms which I did not have a problem with untill I changed the arms for the 5 lug.. Could you explain the "shoulder of the bushing being to high" portion? maybe a picture would help.


Thanks again!

[Andyrew]

Heres a pic of what im planning for the interior.

Its just a tad bit of help for structure, wont hurt my seating, and maybe help if I get T boned, I know, wont do a bunch.. but I think it may help the chassis.

[Porcharu]

[QUOTE=Here's an example of the tubular brace I like. [/QUOTE]

What happens in a wreck - say a bad one where the rear of the car gets all wadded up. Looks like that bar might end up in your back.
I like the idea of the tube for stiffening, but I have been thinking about this potential proplem for a while.

[dan10101]

That tube brace will fold just as quickly as the surrounding metal.. besides the angle at which it is at will put it 5 inches behind the rear seat if it continued in its path of motion.

An accident that bad would kill both driver and passenger anyways, seatbelt's wouldnt hold that much strain and the collision would probably give enough whiplash to kill them as well..


You drive a car like this, You take a risk like that...



Anyways, Sway bar is out. New one next to it.

Old sway bar goes to Kenny (orange914)

New one is a (IMG:http://www.914world.com/bbs2/html/emoticons/ph34r.gif) weapon.. looks to short? 32inches is the firewall to firewall, bar is 37.5 2.25 on each side of play room..
Hardest part will be fabbing mounts for the bushings.

[dan10101]

pic

[dan10101]

pic of car

[dan10101]

sway bar hole a tad small. Need to enlargen and reinforce.. (IMG:http://www.914world.com/bbs2/html/emoticons/sawzall-smiley.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/welder.gif)

[ChrisFoley]

QUOTE (Porcharu @ Mar 23 2006, 03:15 AM)

[QUOTE=Here's an example of the tubular brace I like. [/QUOTE] What happens in a wreck - say a bad one where the rear of the car gets all wadded up. Looks like that bar might end up in your back. I like the idea of the tube for stiffening, but I have been thinking about this potential proplem for a while.

I whacked the left rear corner of my race car at 100mph against an armco barrier. I never lifted.
The pickup ear folded around the end of the tube reinforcement. The firewall is quite strong along the bottom edge where it is welded to the floorpan and there is a second layer a couple inches forther forward. There's no danger of injury from that tube.

[Jeroen]

andyrew,
the pic below shows 2 situations
in the top one, you will see that the shaft is slightly protruding beyond the shoulder of the bushing

the bottom one, the bushing sticks out farther that the shaft
this is not good

the shaft should mate to the suspension pickup on the chassis to prevent it from rotating (and loosening the bolt)

if this happens, you need to remove some material from the bushing so the shaft "sticks out" a bit

re: doorbar design
remember that the middle of the long is it's weekest point taking stress away from other parts of the chassis and focusing it to the middle of the long (as in your sketch) might not be a good idea

[maf914]

Andyrew,

You might want to go back and check out the 914RS build thread and look at the reinforcing tube work Joe did in the cockpit. If I recall correctly, he built a partial tube cage that extended from the rear firewall to the forward part of the longitudinal. Not a complete cage but a reinforcement that ran low from the firewall forward. Your idea looks similar.

[Andyrew]

QUOTE (Jeroen @ Mar 23 2006, 07:37 AM)

andyrew, the pic below shows 2 situations in the top one, you will see that the shaft is slightly protruding beyond the shoulder of the bushing the bottom one, the bushing sticks out farther that the shaft this is not good the shaft should mate to the suspension pickup on the chassis to prevent it from rotating (and loosening the bolt) if this happens, you need to remove some material from the bushing so the shaft "sticks out" a bit re: doorbar design remember that the middle of the long is it's weekest point taking stress away from other parts of the chassis and focusing it to the middle of the long (as in your sketch) might not be a good idea

Thanks, That helps a bunch!

Also I'll move the pickup points further.

How bout this?

[Aaron Cox]

stop pussyfooting and do a real doorbar (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/mueba.gif)

[J P Stein]

I seam welded everything from the after firewall back.
Nuthin' has broke in 4 years of Axing on a rough venue.....(insert fingercrosssing smilie here). I saw no noticable warpage.

I've seen uni-body prep articles & vids for racin'. The first thing these race shops did was seam weld everything in sight. I dunno if it has done any gud on my car, but it didn't hurt. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)