Mythbuster: continuing project thread of my 1303 '75

[Wally]

Originally Posted by ricola

Just a thought, will these inner uniballs work without mods on a bug chassis? I know the inner bushes are normally different but can't remember how exactly...

Nobody tried that afaik...I noticed the outer diameter is (about?) the same. Difference is ONLY that the bug's torsion tube had 4 indentations (sp?), but I guesstimate that these urethane outer parts don't really need a 360 degree contact path to seat against... Only one way to try it right?
I had also ordered a set of bug IRS black urethane grommets, but Topline was out of stock at the moment and I want the arms back in... so I'll try the 944 parts first I think.

Also, what overall spring rate do you have at the back and how do you find it? I'm trying to work out roughly what springs to get for some coilovers in addition to the stock torsion bar...

Your quest/questions are the same as I have Richard...
All I know is the former 23.5mm bars were too soft for my heavy tranny/engine/intercooler/turbo and all that, so the logical next step was 25.5mm.
There is no more science to it than that

Test and try, test and try.. Its a bitch, but someone has got to do it

[Xellex]

also, it looks like the hole through the trailing arm bushes is too small. Are you using the stock beetle bolt, or the porsche (thinner) one?

[Wally]

Originally Posted by Xellex

also, it looks like the hole through the trailing arm bushes is too small. Are you using the stock beetle bolt, or the porsche (thinner) one?

I don't understand the q...

[Xellex]

well, you know how the beetle trailing arm bolt has a bigger diameter than the porsche one, and that you need to pull out the porsche bushings and replace them with the beetle ones, to make that bolt fit through.
Now, from your pictures, that hole looks to be too small to use the beetle bolt. That's why I was wondering, if you made some modification to your chassis, to be able to use the porsche bolts

[Wally]

Originally Posted by Xellex

That's why I was wondering, if you made some modification to your chassis, to be able to use the porsche bolts

Ah, yes, now I understand what your saying: yes, I did convert to the 12mm Porsche 944 bolt by welding in 12mm nut(s) deep within the forks

[Wally]

This weekend I have welded in the cage. Its not 'bolt-out' anymore, but the extra structural stuffness by welding the A- and B-pillars to the cage had my priority


Cage is really close to the A-pillars which I really like. It makes welding easy.


I made a bracket to bolt to the former seat belt mounting points so I can keep the head liner and inner trim intact:


Next making the dash fit...

[dub_crazee]

looks like you;ve got your hands full there wally - the poly bronze bushes look interesting - im keen to know how theyl turn out for you this year

ive just fitted the weltmeister (sp?) ones to my spring plates - theyl do for now

out of interest have you considered uniball / coil over set ups.....i like the idea of the adjustability.

keep up the good work

deano

[owdlvr]

Wally, regarding your A-Pillar mount you should consider re-doing this or removing it. You need a much larger bracket (on both the A-Pillar and Main Hoop side) to spread the loads. Small brackets break off the cage or a-pillar and become a significant safety issue.

[Jim]

Wally, very nice job indeed ,but i agree with owdlvr for re considering the A-Pillar mounts and if the welding will be kept massive especially when the weight distribution changes drammatically in a race track.

[Wally]

The A-pillar got two places now where it is attached to the body: one midway (top door hinge) and up top, just before the head liner begins (the one in the picture). The B-pillar is connected as pictured.
I really fail to see how and why this would tear off other than in an accident...
Could one of you two explain how a force great enough, even in 'extreme driving' could/would cause this?

I would really need to see that happen to believe it myself, so I am NOT going to weld in any bigger supports, but do thank you guys for the concern. It would help though if I could picture it why/how your scenario could arise.

Not to mention I have seen this near exact way of connection in some welded 911 cages/cars, at least the A-pillar points and welds..

[MX67]

Wally, You will not use slicks, I assume (at least for now), so I can't see why would this welds break. They will be OK.

But, using slicks with alot of grip and applying too much force can tear those tiny connections off.

It ususally breaks when breaking hard. I was driving many race cars and those cages have more welded connections.

[owdlvr]

I really fail to see how and why this would tear off other than in an accident...

I can't speak for the others, but _my_ comments were in reference to the tab on your b-pillar breaking off in an accident. They have the potential to kill you if they do break, as it leaves an exposed cut piece of metal. I doubt you would find a racing body that would log book a cage with those tabs, as they aren't safe. Considering a cage is for safety, those small tabs are going backwards.

Your A-Pillar welds don't pose a safety concern, so there is no problem there.

You are correct that plenty of cages tie the main hoop into the b-pillars, but the surface area for attachments should be much larger. Here's an EVO6 cage (sorry for the small photo) that should give you some idea of the surface area used at the contact points:



-Dave

[Wally]

Originally Posted by owdlvr

I can't speak for the others, but _my_ comments were in reference to the tab on your b-pillar breaking off in an accident. They have the potential to kill you if they do break, as it leaves an exposed cut piece of metal. I doubt you would find a racing body that would log book a cage with those tabs, as they aren't safe. Considering a cage is for safety, those small tabs are going backwards.

Ah, see what you mean now Dave. I'll look into it.

Tnx,
Walter

[Wally]

Getting the dash adjusted for the cage bars:





Trial fit of the dash:

[Humble]

This is the kind of cage I had in mind! Awesome craftsmanship! I really want one of these cages now.

I can't tell from the pictures but how long are the welds on the A-pillar? I like the bolt in nature of the B-pillar additions and I don't think they will break free, but they will probably bend and deflect.