How fast is your car? In the S1/ST4 cars, we are quickly trending towards the realization that Spec Miata cages are grossly under-built for the speeds we're seeing.

 

A cage should be a one time thing, don't think of it as something that you'll later upgrade.
Do it once, do it right.

 

I am using the Miatacage and still have A/C and heat but it requires some adjusting behind the dash. They include instructions for this. I used only the lower door bar so I didn't have to cut the doors. I did raise the lower door bar to a higher position since not using the upper.

It was getting to be too fast for no cage at all but this is a compromise. Be as safe as you want to be. It's not as safe as staying home.

 

 

As Andrew observed, if you are not otherwise limited by rules, go big. Traditional Spec Miata cages are floor mounted only. They provided only the minimal roll over and intrusion protection. Beyond that, they offer only the minimal amount of torsional stiffness increase compared to a fully integrated cage. NASA ST rules allow almost a full FIA cage in ST5. In Supermiata, we are adopting more open rules for cages even in S2 (140whp). S1 goes a step further by allowing a full integrated FIA cage with extensions to the front shock mounts. The merits of a 12+ pt cage attached to the firewall and door jambs go far beyond mere intrusion protection but that should be enough. In most cases, the cost and weight only increase slightly and the car is future proof for additional power/grip/ aero loads.

 

 

A good cage Builder will charge you enough labor on top of the cost of a generic Miatacage to cover the cost of a custom cage generally. So that the perception that you can just buy the $900 Miatacage kit and be done overlooks that it will cost more than that to actually put it in by a competent fabricator. It only takes one flawed weld to compromise the entire cage.

In Supermiata here in California we often tech cages of cars that were approved by scca and NASA for spec Miata. Not a single one of them was properly installed. Not one. We have failed several due to incomplete welds or the structure simply being incorrect. This exposure to the general low quality standard of most cages in Miatas concerns me.

The true challenge is finding a competent fabricator, not designing the cage. Shop around but I often hear prices between 1700 and 2500 for a custom cage.

 

I agree with the statement that a good fabricator is hard to find and worth the money when you find him. My shop had an expert welder come in after it was tacked together to finish it.

Mine has a passenger seat.

 

 

 

Take the car to Mark. I did a miatacage in my first miata and was never happy with it. After seeing a few of Mark's cages, I sold the car with the miatacage, bought a new NB, and took it to Mark. So much happier now. He does really great work.

 

Let an expert build it from scratch his way if he's really good. Discuss your wants and needs and see if you're comfortable with him. Look at some of his completed work for quality. Be sure he's right for you.

 

You really have to decide if you want a street car? IE Blackbird Fabworx and airbag. Swapping seats for HPDE & TT. HANS if using 6 point harness.

Race car / track car full cage, spec Miata as a minimum FIA nice but then cant use for spec? They really should revise the spec cage to a more modern cage setup as Emilio suggests.

IMHO I really cant see using a full cage on the street without a helmet and HANS?

 

I'm with you Blkbrd69 I think a full cage on a street car is crazy.

 

Forgive me for skimming the OP too much. Agreed that a full cage for a street car is a very bad idea. Our general protocol for HPDE safety is to go either full OEM or full race & trailer. Don't mix. To that end, I switched my HNRS to a Simpson Hybrid-S that works with 6 pts in the race car or the 3 pt OEM in the GT350.

Full OEM means all the airbags, stock seat so airbag sensors are still active.

Full race car means 6 pts, 6pt bar or full cage. Padded tubes, race wheel w/o airbag. FIA seat with halo. Nets on both sides. Fire system and hand held. And a trailer to tow it because those bars and lack of airbags are just asking for trouble on the street if you get hit.

 

I think you mean absolute ideal and not general protocol. I don't think I've seen anyone just starting in HPDE go from none of it to all of it as it's simply not realistic for most people. More often than not you see stages of safety improvements based on how fast someone is going. I will agree that once you change seats or remove airbags you need to, at a minimum, have fixed back seats, harnesses, race wheel, some sort of neck support, and a good roll bar or cage as these systems work together.

How far you go beyond that is really up to your personal risk tolerance for the pace you currently drive. I don't think full halo seats, nets, and complete fire suppression system is really necessary if you're not wheel to wheel. Are these things a good idea? Yes. But they are not imperative.

 

This. He did my cage and it is brilliant.
He has amazing attention to detail, ability to adapt, and to customize anything to what you want with over 20 years of experience.

 

I'm getting very close to doing this as well. Seems most impact deaths these days are from occupant side pancaking against concrete.

 

I've been watching a lot of IMSA this year and noticed all the cars ran triangle nets on both sides and the lower classes with open windows still run a window net. Has 2 nets caught on at the amateur level yet?