I am curious about two things on this car/cage.
Why didnt you want the rear bars going to the strut towers? It looks like this wouldnt have been hard if you wanted.
and
What made you choose the more simple door bars? I noticed the “nascar style” bars on the DS seem to be the popular trend.
Mike, you know your cage stuff. ;D
Using the bulkhead instead of the rear strut towers in this case is specific to the car. On the E36 BMW, the rear suspension is not a coil strut, in other words, the springs are mounted inboard on the control arms and the shocks are mounted further outboard where you see the rear “strut” towers. The rear shock tops, since they only house a shock, not a full coil, see pressure in only hundreds of pounds, while the rear bulkhead sees torsion in thousands of lb ft. As per the rules, I can mount the rear of the cage to one or the other, not both. Since the bulkhead is the main source of chassis flex in the rear of the car, it won. If the rear was coil based, it might have been a different story.
Weight was the main reason: NASCAR door bars are big time heavy and would require a ton of weight on the opposite side of the car to balance out my (driver) weight and the NASCAR bars. The NASCAR bars are also supposed to be mounted to the chassis like a NASCAR or other tube frame car. Since my cage can only mount in so many places, putting the entire force of the impact on the A-pillar bar and main hoop isnt a great idea. An X-bar lets me keep the whole shell of the door for strength and once gusseted, will be nearly as strong as the NASCAR bars. The sheet metal of the door is actually better at dissipating energy than a NASCAR or Xbar. Since I dont have a full tube frame car that can take huge hit after huge hit, I wanted to keep the door shell and use an Xbar for the above reasons.
:thumb Interesting stuff, especially the suspension. Its funny to think of how little I know of non-honda setups.
Welds look awesome from what I can say
Jesse hit the nail on the head with both of Mikes questions and put some good answers out. Those that know what a cage will do in the event of an accident are the people serious into this line of business. Simply bending and welding 120+ feet of tubing into a chassis doesn’t make it safe, but rather where that energy is directed and transfered around the occupants. The E36 is an unusual duck with where the chassis actually flexes. It’s very similar to my old Avenger with a massive over loop bulkhead that takes the brunt, rather than the aforementioned struts themselves. Something you’ll find quite typical with most german cars 
I do have the chassis and stress analysis programs(Cosmos) to build and test what a cage or chassis will do, but there was already an overload of that put into this cage design from the get go and didn’t need any further input on my end at all.
Thank you…welding is my key experience. AWS certified welding fabricator since 1997, and certified associate welding inspector since 2001 but I am a little out of date code on the later. Need to get recertified to new code to do any DOT/structural certifications again. Good money, boring as all fuck of a job.
Abutment joints are HeARCo2(Helium Argon Co2) sheilded TIG. Uncommon and expensive mix of gas I use but provides superior localized heat and penetration at the weld pool with lower amperage. Makes the welds more ductile, a good thing in a cage. TIG welds, while clean and strong, are actually brittle and that has no place in a cage or chassis design. Base plates and cage to base plate joints are MIG welded for superior ductility. TIG welding these joints can to lead to fractures or shearing the unibody in an accident. I just eliminate that via MIG.
thats awesome dude. thats the koolest jungle gym ive seen ;D are you guys going to paint it or powdercoat it?
Paint, Jesse is going to paint it factory white exterior color.
Yeah and I suck at arts and crafts time so it’ll probably come out like ass.
need some help?
nail gun+rattle cans of AWIII=spray bomb.
Adam, you do some Uber work on cages, my man. Look at this 911 GT3 RS’s cage, thats pretty much what you’ve built :bowdown :bowdown :bowdown
holy shit it is!
Jesse do your cage bright fuckin orange!!! :rofl
or PINK!
That’s a wussy bolt-in bar. Lame.
x2
x3…that’s a Porsche Tequipment modular bolt in cage. You can buy another front section and “add on” to the rear section(note the mount tabs for such an adaptation.
Couple pictures to add of the foot protection and the complete door bars with flare gussets:
O tits! That looks sweet!
Sweet. :bowdown
very nice!!!
jesse, can’t deal with no heat huh?
heatercore bypass FTW! :tong
Haha! Good eyes. It’s not so much for me, I’ve never turned it on since it became a track car (adrenaline takes care of me), but I need it for a defogger for rain and frosty spring/fall mornings. FogX doesnt help against ice. ;D
yeah bro i hear ya on the foggy glass, can be real annoying, and even dangerous at times…
i ran a heatercore bypass on my old passat, worked well, but i’d have to agree pita not having the defrost.
for an all out track car, i’d def. ditch it, since i wouldn’t run it in cold weather anyway.