Chassis Stiffening - which kit? Cage?, Stiffening before paint, need help. Options

[corpselaurel]

I have been reading and searching. So far I have eliminated the boxed trailing arms.
I want to stiffen the car up before I paint. What 'kit(s)' should I install?

I have read read that most of the pieces in the chassis stiffening kit are useless. Should I buy the kit and install the others?

I have also read that engman's kit helps a lot. And I was also considering the Inner Rocker Panel Frame Stiffeners.

I just don't know which combination I should install. Should I use all of them or do some cancel each other out (for lack of better wording). Post links to suppliers if you mention any.

I am open to the idea of putting a cage in but it has to be in kit form. Does anyone sell one and would I still need any of the stiffening mentioned above with a cage?

The car is not badly rusted except for the battery tray and underneath - completly gone. I will be repairing it. My plans for the car are daily driver with some autox. Next year I will swap in a more powerfull engine. Thanks for any help.

[Trekkor]

I recommend Engman's highly.
Nice thing is you can install it any time because it goes under the carpet kit and is concealed from view.

This kit really works. I tend to drive rather spirited on the back roads and this is a good boost.

Send your e-mail and I will send you a few pics of the easy install.

KT

[neo914-6]

few pics of the easy install

Why not post them for all to see??? (IMG:style_emoticons/default/biggrin.gif)

[corpselaurel]

Here is a pic of the kit from pelican. Which pieces should I not use?
And should I install engman's and the Inner Rocker Panel Frame Stiffeners as well or just engman's? I just don't want to have to strip off por15 later on to weld more parts to the car.
Any cage kits as an alternative? After reading through some threads I am starting to worry about cracking due to high spring rates.

Which pieces should I not use?

[Trekkor]

Believe me I want to. I have over 50 shots of the entire install start to finish as a photo documentary ready to post.

It's not time yet...sorry.

I'll give one teaser. (IMG:style_emoticons/default/monkeydance.gif)

[Trekkor]

My understanding is this: if you box stiffen the trailing arms , something else has to give. Like the trailing to chassis bushing mount points. Very bad and costly. Rips and tears.

I landed a 3 wheel off the ground right turn in my Baja Bug of old that had a solid trans mount kit. Ripped the rear mount horn right in half. (IMG:style_emoticons/default/headbang.gif) Some areas of the car need flexabilty.

I honestly dont know if the box kits help or not. (IMG:style_emoticons/default/confused24.gif)

[corpselaurel]

My understanding is this: if you box stiffen the trailing arms , something else has to give. Like the trailing to chassis bushing mount points. Very bad and costly. Rips and tears.

I landed a 3 wheel off the ground right turn in my Baja Bug of old that had a solid trans mount kit. Ripped the rear mount horn right in half. (IMG:style_emoticons/default/headbang.gif)  Some areas of the car need flexabilty.

I honestly dont know if the box kits help or not. (IMG:style_emoticons/default/confused24.gif)

In my first post I stated that I have eliminated the trailing arm kit (for the exact reason you mentioned). I am trying to sort out everything else.

I know that some of the pieces in the picture I posted above don't really do anything; I just don't know which ones.

[Trekkor]

Come to the Napa 914 lunch July 19 and see/feel the install for yourself.

Napa lunch info

I should have the carpet in by then, but I'll bring the complete photo pack for all to see.

[corpselaurel]

I would but it is way to far from me. It is in AZ right?

[i love porsche]

so the trailing arm stiffeners are a bad idea?

[Trekkor]

My understanding is the load get's transfered to the chassis mount points and can cause cracking, splitting or failure over time.

So yes, bad.

[Eric_Shea]

I have them (boxed control arms)... I don't think they're good or bad.

From what I understand they're fairly useless. The factory did it to chase after rear flex which was eventually found to be in the bushings. I really don't see how the extra stiffness could translate through the factory rubber bushings... they're quite substancial.

Now, if you had roller bearings then it might add to the issue but with stock bushings I can't see it.

Regarding the chassis kits... I have the basic factory style kit pictured above. I've heard good things about the inner longitudinal kits but no experience.

[corpselaurel]

After doing some more reading I haver decided to install the clam shells, the inner longs, and the 10 piece kit pictured. (I really wish someone would call out the pieces that I hear are useless in the 10 piece kit, I don't want dead weight. I even numbered them!)

My main concern is with the rear shock towers. I have read that with high spring rates (~300# I believe) they start to separate over time. There doesn't seem to be any kit to fix this that I am aware of. (Please let me know if there is, or if someone does it) So I will wait to tackle that problem until next year when I hope to have a cage put in that ties to the rear shock tower. This page has been very informative.

I will go ahead and do the welding, and por15 everything. And when I am ready to install the cage I will remove the por15 where I need to weld I guess. I will not be doing the boxed trailing arm kit. I read in a few posts on hear that for various reasons convinced me.

Which ones are useless?!

[Eric_Shea]

I believe it's 6 and 7 but not certain.

It doesn't matter because you can't put them on your car anyway. They only go on six cylinder models. They go where your engine mounts currently reside. So... unless you want to cut off your mounts and go with a six you have no worries.

[IronHillRestorations]

From what I understand they're fairly useless.

There's a areospace engineer in the Texas/MUSR group, Al Swanson, who did some analysis on the 914 rear trailing arms, and found that welding the kit to them may actually WEAKEN them, due to anealing the metal, which takes the strength out of it.

From what I've been able to discearn, the trailing arm box kits are pretty much about marketing, and bragging rights.

PK (IMG:style_emoticons/default/cool.gif)

[Jeroen]

If you're planning to put a cage in your car, I wouldn't mess with any of these kits

Waste of time/money IMO (if you're doing a cage) plus you're adding a lot of weight to the car (which will become mostly useless once you put the cage in, and will be pretty much impossible to remove then)

If you feel you have to do something now, I'd go for Engman's kit.
I wouldn't do the out side clamshells (unless you have rust issues on the outer longitudinal)

About the GT-style chassis kit. I think you need the pieces that reinforce the the outside suspension pick-up points and ties them to the frame rails. The ones that go higher up (outside of the shock towers and further back).
That's what I seem to remember anyways. There was a thread here that showed which pieces to use and not to use.

We've had some pretty good threads about cages and the GT chassis kit when this board was just a few months old. I'll see if I can find them for you.

cheers,

Jeroen

[Brett W]

In my opinion 3 and 8 are fairly useless, but I think a lot of cars already have them in there. My car had them, the other car that I am doing work on have them and several chassis I have seen have them. MAybe the factory started putting them on the later cars. I have the factory kit and don't know if it made much difference.. I may try Engmans kit when I get the chassis pulled back into shape.

As far as the trailing arm kits go, the trailing arms don't flex they twist. Look at how the load paths are applied. If you want them stronger, make new ones and make them round.

[Eric_Shea]

(IMG:style_emoticons/default/agree.gif) with Ya-Roon

If you're going cage the rest is "probably" useless. I would do the cage and pieces of the factory kit which tie the suspension in further to the chassis.

[RAR]

From what I understand they're fairly useless.

There's a areospace engineer in the Texas/MUSR group, Al Swanson, who did some analysis on the 914 rear trailing arms, and found that welding the kit to them may actually WEAKEN them, due to anealing the metal, which takes the strength out of it.

From what I've been able to discearn, the trailing arm box kits are pretty much about marketing, and bragging rights.

PK (IMG:style_emoticons/default/cool.gif)

I've heard of this, but haven't heard the details. If mild steel is used for their construction (likely) they wouldn't harden sufficiently in the first place to allow for any annealing. If they were a high carbon steel (unlikely) they should have been hardened to a point that allows flex, but only after considerable stress (hard driving), flexing being preferable to breaking.
Application of heat can make things more brittle. Perhaps that is one of the objections to welding on the boxed arm kit. I wouldn't think that careful welding would do that much harm, and thicker metal would be better in general. I'm not supporting one point of view over another, but would like to see more data.
The transfer of stress (reinforcing one point transfers the load elsewhere) does sound viable. Making the components round to stop twisting also sounds good.

[Qarl]

Has anyone bought and installed an off-the-the shelf roll cage?

Autopower
Stable Energies?

Just wondering if anyone has BTDT?