Blackbird fab "90%" cage, what sayeth you?
08-06-2012, 08:09 PM
#23
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Join Date: Dec 2011
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Optimally, you would be able to remove and re-install the left bar for street/track use. Unfortunately, Im not sure there is a way to do this and still be structurally sound. Maybe someone with more of an engineering background would be able to chime in.
In theory, when you are driving a normal car, your head is only protected from the roof/b pillar/steering wheel, etc by --- nothing really. In what way is a steel bar with the SFI dual-durometer padding covering it less safe than an oem application at street speeds? I can bang my head on the dual-durometer stuff and its not pleasant, but idk that it would hurt me any more than banging it off of the unprotected hardtop.
In theory, when you are driving a normal car, your head is only protected from the roof/b pillar/steering wheel, etc by --- nothing really. In what way is a steel bar with the SFI dual-durometer padding covering it less safe than an oem application at street speeds? I can bang my head on the dual-durometer stuff and its not pleasant, but idk that it would hurt me any more than banging it off of the unprotected hardtop.
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08-06-2012, 08:41 PM
#24
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That would depend on your cage design. In my case, the only thing I can touch with my head while strapped in is my headrest and my roll bar.
Also, windows are relatively soft, steering wheels should have airbags. your seat should ideally be far enough forward to prevent you from hitting the B pillar. The roof could be an issue, but at least its flat and fiberglass which is a LOT more forgiving than even foam covered steel. Also, the cage tubing will always be at least 2 inches closer to your head than the roof.
Also, windows are relatively soft, steering wheels should have airbags. your seat should ideally be far enough forward to prevent you from hitting the B pillar. The roof could be an issue, but at least its flat and fiberglass which is a LOT more forgiving than even foam covered steel. Also, the cage tubing will always be at least 2 inches closer to your head than the roof.
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08-06-2012, 09:12 PM
#26
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IMO, that type of cage in a street car is asking for trouble. You're mildly mitigating one risk (serious injury in roll-over) and substantially increasing the liklihood of another (bashing your unhelmeted head if rear-ended on the street). IMO, the risk added in the latter greatly outweighs potential gain from the former.
Is it a street car or a track day car, or a race car? These require 3 different approaches for safety measures, in a some-what mutually exclusive manner.
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08-06-2012, 09:19 PM
#27
From the sound of it Hustler really wants a weird combo cage. Like a roll bar with true nascar bars and maybe a diagonal from the middle of the roll hoop (far enough away that head contact is not possible) to the passenger footwell. Pretty sure that cage would be illegal in every form of motorsport but I think that would really give him want he wants.
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08-07-2012, 10:47 AM
#33
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Well, this thread went gay.
I'm leaning toward doing a custom roll bar to get it high and forward for the most roll-over protection possible.
It's a "trackday car". When I build the PTE/D car it will get the "family man" cage.
I'm leaning toward doing a custom roll bar to get it high and forward for the most roll-over protection possible.
It's a "trackday car". When I build the PTE/D car it will get the "family man" cage.
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08-07-2012, 11:24 AM
#34
I've cut many people out of cars, that while still wearing their seatbelt, have bashed their heads against the windshield, A and B pillars. The kinetic energy from a serious collision will cause the body to stretch and flex in ways that are difficult to comprehend.
I'm not inclined to street drive a caged car.
I'm not inclined to street drive a caged car.
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08-08-2012, 01:32 PM
#36
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Got an email with a link to this thread, guess I should reply 
The Blackbird Fabworx street cage is basically the most hard core piece on the menu for streetable cars that I'm building.
It is not meant to be a full race cage but it is built so it could easily be upgraded in the future into one in case you wanted to -
For race legality purposes, all you'll need to add are the two bars that go between the front and main hoops above the windows.
I'd also recommend adding a cross bar inside the dash (optional per NASA CCR), in a car that has full interior, HVAC and audio system it's not something that I normally do.
For a street-track car, this is as good as roll over protection gets short of having a helmet, HANS, full containment seat etc...
It is a 12 point design that is well braced and gusseted, it clears the hardtop by about 1/8" everywhere so the fitment to the car is nice and tight giving the driver the maximum space possible.
The version that you see is a HT only fitment BTW, though making one that is soft top friendly is completely possible.
RE: Smacking your head -
One of oldest arguments in the miata world is around smacking your pumpkin on a roll bar.
If you feel that you're okay with a normal 4 point roll bar being next to you, you'll feel just fine with the BFW street cage - the hoops are as high and as far from the driver as they can be and the dog bone brace is a good 8.5-9" away from the driver's head.
Compare that with the OEM soft top bracing that resides right next to your head.
The end.
Here's a shot of Scott's car (same one in the OP) from MRLS, shows the distance pretty well -
You can also see that the dog bone isn't flat, the braces follow the contour of the HT to give you the maximum space.
RE: door bars -
I find that any type of door bar makes the car a little harder to get into or out of, more so if you have a racing seat, and even more if you don't have a quick release steering wheel.
So if you're looking for the OEM ease might as well scrap any kind of door bar and keep the OEM seats.
However, Shaikh from Fat Cat Motorsports has one of my Street cages in his car and made this video -
Fat Cat Motorsport's "Senna" with Blackbird Fabworx Street Cage - Ingress/Egress - YouTube
This is with OEM seats and steering wheel.
A racing seat wouldn't have made this any harder because the leg bolsters would be about the same height as the door bar, a QR will make it even easier.
Before the first guy jumps on the pink cage having different door bars, yes, the design is different but the dimensions are rather similar.
Here's a link to the M.net thread with Shaikh's review of his street cage and a link to a nice gallery showing it from every angle -
FCM's 95M, "Senna", with the first Blackbird Fabworx 12-pt street cage - MX-5 Miata Forum
Moti
It is not meant to be a full race cage but it is built so it could easily be upgraded in the future into one in case you wanted to -
For race legality purposes, all you'll need to add are the two bars that go between the front and main hoops above the windows.
I'd also recommend adding a cross bar inside the dash (optional per NASA CCR), in a car that has full interior, HVAC and audio system it's not something that I normally do.
For a street-track car, this is as good as roll over protection gets short of having a helmet, HANS, full containment seat etc...
It is a 12 point design that is well braced and gusseted, it clears the hardtop by about 1/8" everywhere so the fitment to the car is nice and tight giving the driver the maximum space possible.
The version that you see is a HT only fitment BTW, though making one that is soft top friendly is completely possible.
RE: Smacking your head -
One of oldest arguments in the miata world is around smacking your pumpkin on a roll bar.
If you feel that you're okay with a normal 4 point roll bar being next to you, you'll feel just fine with the BFW street cage - the hoops are as high and as far from the driver as they can be and the dog bone brace is a good 8.5-9" away from the driver's head.
Compare that with the OEM soft top bracing that resides right next to your head.
The end.
Here's a shot of Scott's car (same one in the OP) from MRLS, shows the distance pretty well -
You can also see that the dog bone isn't flat, the braces follow the contour of the HT to give you the maximum space.
RE: door bars -
I find that any type of door bar makes the car a little harder to get into or out of, more so if you have a racing seat, and even more if you don't have a quick release steering wheel.
So if you're looking for the OEM ease might as well scrap any kind of door bar and keep the OEM seats.
However, Shaikh from Fat Cat Motorsports has one of my Street cages in his car and made this video -
Fat Cat Motorsport's "Senna" with Blackbird Fabworx Street Cage - Ingress/Egress - YouTube
This is with OEM seats and steering wheel.
A racing seat wouldn't have made this any harder because the leg bolsters would be about the same height as the door bar, a QR will make it even easier.
Before the first guy jumps on the pink cage having different door bars, yes, the design is different but the dimensions are rather similar.
Here's a link to the M.net thread with Shaikh's review of his street cage and a link to a nice gallery showing it from every angle -
FCM's 95M, "Senna", with the first Blackbird Fabworx 12-pt street cage - MX-5 Miata Forum
Moti
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08-09-2012, 12:49 AM
#38
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Join Date: Oct 2009
Location: Portland, OR
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Nice, thanks for sharing Moti. I remember watching your car Blackbird's evolution on forumz - I always appreciated your unique approach to solving problems. Will keep your fab work in mind when I'm evaluating options for my track car in the future.
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