Modifying rollcage - struts? Any Experts?

[reanimation]

Hi Retro Riders

Here is a situation I have and am critically assessing. I want to use my cage (currently trial fitted) to tie in the struts for a little bit more rigidity. i don't think they were made mega tough, so cage is a good thing IMO, i just wanna tie the front in while am at it. Prob is, its not going to be racer stylz so criscrossing the doorbars is not an option i want to choose.

So far the idea I'm playing with is strengthening bulkhead with sheet and welding through, then perhaps gusseting the bend in the A pillar legs (meaning a bigger hole in the dash) or adding a short tube to triangulate it. This ideally will spread any force from the struts if the worst happened in a crash.


Heres a very 5yr old MS paint of the proposed design (seem to have missed a door bar ignore that).
Black is the standard cage, blue is the bits I plan to add and brown is me moving (and modding) the 'centre' bar up to the top of the screen, so the new blue bars incorporate a more dash forgiving new centrebar.








This comprehensive racing OMP cage available on eghey uses both a gusset, and a triangulate bar, and then a brace on the strut arm, brace is an option.



So my options are: A) carefull add the blue mods, or B) Fugg it and just have a cage, if the car bends it bends! ;D (theres no C - no cage )

---
And a great reference for mega builds (overkill in my case but interesting/useful)
www.e30m3performance.com/tech_articles/cage_symposium/cage_symposium.htm

[haggis]

i would add the blue mods, seems fine

[popuptoaster]

Seems like a lot of extra weight in the front of the car for probably minimal handling improvement especially when one of the advantages of having a 3 door Sierra is that they don't weigh much, Ford seemed to think the strut tops were strong enough to suport a heavy old Cologne engine AND take the extra forces of driven front wheels in the 4x4 versions.

[slater]

Its the same old problem with bringing the cage through to the struts tbh, Its good for ridgity but you loose some crumple zone effect so probably makes it less good in a crash imo.

Cant see any real problem with you doing it like that but i wouldnt bother if it were mine.

[gn3dr]

Sierra strut top are notorious weak spots. Hit a bad pot hole and it is possible to bend the inner wing.
So it is worth doing to strengthen the front of thecar up. (along with a good strut brace of course - not the single bolt at each end type - get a Graham Goode type one with two bolts on each end.

[reanimation]

May 1, 2008 17:19:08 GMT gn3dr said:

Sierra strut top are notorious weak spots.

I was sure i'd heard summat like that before, and that crash video demonstrates it a bit too, though Hit a tree head on at 90KMH and ya done for in most cars! It was a bit of a light time for car building with materials, which does help losing weight, however, this is my first actually torquey car with some power so I wont worry too much about the weight yet.

Thanks for ALL the responses, all VERY helpful on my Christmas card list.

[nobody]

i don't think you need the extra gussets on the bends.
the bend is the strongest part of that roll cage at the front.

just seams like over kill.

i take it the blue ones running forward are going to tie into the area around the top of the struts.
you could then just use a normal strut brace across them instead of the fixed horizontal bar.

the horizontal bar should ideally be between the two bends and not forward of it as you would have a week point on the cage.

[reanimation]

noted. -thumbs up smilie-

[cptsideways]

Just a chassis brace across the struts but tied into the centre of the bulkhead would be much better, if doing it to the cage that also needs to be fixed to the A pillar or under dash cross brace or both.

[bstardchild]

Monza front turrets are very soft - even when not rusty/crusty

If it's any help here is my roll cage (mspaint) with some of the things I was thinking about when planning it

[reanimation]

More food for thought and nice one for finding it on page 2 or 3.

Cpt I think I follow what you are saying there, I've had a few untrained ideas that have it joining up a bit like that.

BC Awesome MSP skill0rz, i've seen a few Monza creaky upfront on here thanks to you and pheonixc cheers for showing me that design. Did you just design it after seeing a few in cars or did you get any pros on the case? looks smart.

Right, once me chores are done back to the drawing board! cheerz

[bstardchild]

May 4, 2008 17:29:24 GMT reanimation said:

BC Awesome MSP skill0rz, i've seen a few Monza creaky upfront on here thanks to you and pheonixc cheers for showing me that design. Did you just design it after seeing a few in cars or did you get any pros on the case? looks smart.

I had some help from people on here - Keefy and CR500Dom, plus a couple of chaps on the ABS forum, but the drawing didn't really change that much to be honest