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Blackbird Fabworx custom 12 point three-quarter cage

11K views 39 replies 20 participants last post by  Blackbird 
#1 · (Edited)
There were a couple of priorities when it came time to pull my hard dog roll bar out and get serious.
- This is a street car (sort of), so street safety was key – no bar by the side of my head.
- I wanted serious side-impact protection, and I want to do tarmac rally down the road so I needed maximum protection for a navigator as well as myself.
- I wanted a rear section and main hoop that was much stronger than your standard roll bar because without a full cage, the main hoop is my primary roll-over protection.
- Needed to maximize headroom - higher main hoop / lower seat mount
- Most importantly, I wanted something that serves a HUGE purpose beyond safety – I wanted a design that focused on chassis rigidity.
- Needed to be awesome enough that I would never want to change it (except to convert it to full cage some day).

Who better to take such a list of needs to than Moti at Blackbird Fabworx? I had a pretty specific set of custom needs, and I wouldn’t trust just anyone to start taking a welder to my car…

Through many emails and phone calls, we decided on a back-section of a NASA approved cage (with a special GT-3 inspired twist as you’ll see in the pics), full door bars that stretched to the front firewall, 12 points of contact with the chassis, and a new custom seat mount for maximum head room. Beyond that though, I really didn’t know how it was going to look – in Moti’s words, “Let’s do something nobody has ever seen in a Miata before” - I felt it was best to leave the artist to do his thing...

The process of having Moti work on my car was enlightening. There are so many little elements that set his stuff apart. Moti emailed me many nights thoughout the two weeks he had the car with progress updates, pictures, and explanations of all the little things and why he did each thing precisely the way he did it. I had already been sure he was the guy I wanted doing the work on my car, but learning along the way about all the details that make what he does so optimal made me glad I went to nobody else. There’s a lot of proprietary stuff here. Meet up with Moti and find out for yourself ;)

Seat Mount:
Basically the only request I had for Moti was to get the seat on the floor. This required cutting out the rear seat mounts as well as a section of the Transmission tunnel and weld in a new piece to make room. New mounts were made, and where they touch the floor thicker sheet metal was welded in to disperse the load. Basically, the seat mount is now a part of the cage.

The result is a good inch and a half lower than I was before – and I was already running no sliders with the sidemounts bolted directly to a Corbeau bracket. Now I can’t slide my finger between the seat and the floor! The magic here though is that Moti perfectly replicated my preferred seat angle and the distance from the pedals and wheel that I had had before while dropping the seat drastically. Even better, the new mount places the seat perfectly centered with the steering wheel. No small feat.

Three-quarter Cage:
Named so because this is a full back-half of a cage, plus the full door-section of a cage. All that's missing is the forward bar by the head.

This whole design is function first with chassis rigidity as a main goal. As we all know, the center section of our cars is the weak spot. This is the main area that I wanted greatly enhanced and with Moti’s 12 point design that spans from the firewall all the way to the rear shock towers, it was exactly what I got. Each bar used for the doors has only a single bend in it which is fully supported - a key for creating maximum chassis stiffness, as is the 12 points where it ties into the car. Another cool element, the harness bar spans the full width of the main hoop – knowing I would have instructors/co-drivers on the passenger side meant having proper harness geometry was essential on both sides of the car. And in the rear section, to provide maximum rigidity to the rear shock points, and as a tip-of-the-hat to Moti’s more street-oriented GT3 roll bar, he did the same gusseted X between the rear legs.

At one point, Moti said to me that we should call it the “how the hell did we fit two spec miata cages into that car” because some off-the-shelf spec M cages have just 6 mounting points to the car ;)

Weight is a key element of course. Most 6 or 8 point cages come in at 100+ lbs. This cage has twice as many mounting points to the car but uses multiple thicknesses of bars to achieve a weight of only 71 lbs including all the mounting points. Since I removed my Hard Dog roll bar to make way for this, and just recently got a carbon hard top w/lexan window to replace my old glass window soft top, the car is nearly the same weight now as when it was a few weeks ago before this went in!

We finished it all off with a Pearl White paint which really pops with the red and black of the car.

What’s more, I would have waited a month for this kind of work. I gave Moti no timeframe in which I needed the car back and yet he had it back to me in two weeks! I know the last couple days he put in close to 12 hours a day. Thank you Moti. Your hard work really shows!

And how does it feel? Incredible. I’ve only driven it back home so far, but on the highway the car has completely transformed – the whole thing acts in unison as one element to bumps and dips and has zero hesitancy when I give it input, instead of the classic miata character of every corner sort of responding at its own pace – which it felt like even with the hard dog roll bar.

Enough words, time for the pictures!

-Ryan

A teaser progress pic Moti sent to me in the second week:


Custom seat mount - cut/welded trans tunnel, integrated harness mounts. :cool:


A mile of headroom = happy!!!! What now, broomstick test??












Homage to the GT3:








All the way to the firewall:
 
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#6 ·
No not at all.

This is a complete weld-in cage back half - the rear legs go all the way back to the shock mounts, and the main hoop is a full to-the floor hoop w/ diagonal brace, etc. The ONLY thing it shares in common with the street GT3 roll bar is the X brace.
 
#11 ·
Gotcha. No, in fact the passenger seat (Momo Start) always sat ~3" away from the back wall - it's got a nice thin-backed design, so it sits exactly in the same position as it did before, the back of it just barely grazes that bar.

I sat in the passenger side while we were installing/adjusting all the harnesses, and with my legs stretched out fully, I can just barely touch the firewall with my toes, so there is LOTS of room.

-Ryan
 
#16 ·
Stuff looks great.... ThePass... I can take down, but I think it'd be a good comparison to how low your seat is.

I had a Sparco Circuit from my other car, great seat, holds you in, wish I never sold it (would love another) but before I sold it, I mounted it in the Miata which at the time I was using stock rails and brackets (stock rails are lower than most BRIDE rails.. I've used 2 different versions).







Seat sat VERY high... and steering wheel clearance was a PITA.



^that was an Autopower Street bar, main hoop was very low.

 
#20 ·
greeenteee - that shows exactly how much of a PITA it is to fit this seat into a miata properly! The halo makes it really tall and wide up top. I see you didn't have a top on or the window up ;) - both things that are nearly impossible with this seat if it is not dropped to the floor. My soft top used to scrape the halo when putting it up or down, and I had to mount it slightly crooked/tilted so that it cleared the window, and that was with no sliders. Now there is a ton of room in every direction!
-Ryan
 
#33 ·
Thanks for the extra pictures Moti!



The tube going to the firewall has a huge gap between it and the clutch pedal. Like, I can fit my foot between the tube and the pedal. Like I said, the whole door section of this is pushed so far to the outer corners that it is completely unintrusive to the driver - If I couldn't see it out of the corner of my eye while driving, and couldn't feel the awesome amount of stiffness it provides, I wouldn't know it was there while driving. My feet/knees/elbows/etc. have as much room as always.

-Ryan
 
#34 ·
That's a great cage.

One question to Moti : do you have a tig welder ? The welds would trully compliment the quality of your engineering and packaging (not saying that your Mig aren't nice !!)

Ryan : when is your next track event ? Give us more than highway feedback ! :D
 
#36 ·
aww make it dec 10th... i'm already signed up for that day.
 
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