NC roll bar and seat

[Custardtart]

I’m prepping an NC for Sprints and Hillclimbs and have a few questions. Does anyone have any idea where to get an engineered roll bar for an NC?
Also, what fixed back, 5 point seats have you fitted? The car will be dríven to events so everything needs to be engineered. I believe Velo seats can be engineered here in Qld but keen to see if there’s other options people have tried.

[Dan]

Brown Davis sell a rollbar with removable rear stays which is the only way to have a removable roll bar which also allows you to use the soft top as well as being the only CAMS compliant removable rollbar I know of so while it is sort of expensive it's your only real option if you want a bolt in cage (https://rollcage.com.au/product/mazda-mx5-nc-soft-top/). The reason they need to put in a removable rear stay and not just put rear stays in lower on the roll bar like you'll see on roll bars from US companies is due to the CAMS regs which require a specific angle as well as specifying the section where the rear stay meets the main part of the cage.

One benefit of the Brown Davis rollbar is that it comes with documentation showing all of the specifications of the rollbars construction which the engineer can have a look at.

If you want to run a hardtop on your NC you need to know that the Brown Davis rollbar will not fit with a hardtop. I learnt this the hard way because I got a carbon hardtop which forced me to sell the Brown Davis rollbar, rip out the soft top and install a weld in half cage.

Regarding a seat I think you will find that no aftermarket fixed back seat will able to be engineered regardless of it's certification because the NC has seat airbags which you are removing by putting aftermarket seats and the authorities don't like airbags being removed. You can get rid of the airbag light no problems with the drivers side light being remove by putting a resistor in the airbag plug and on the passenger side you can put a resistor in the plug as well as cut the weight sensor out of the stock seat and plug it in.

Most seats should fit fine in the NC with either a fixed side mount or sliders unlike the earlier cars and I installed a few different types including a Racetech RT4009W, a Cobra Imola Pro and a Cobra Suzuka pro. I think the max width of seat you can run in terms of the wing width is about 59cm which was the width of the RT4009W I had as that just touched the door.

The photos on the brown davis website are for the NA/NB roll bars but this is what it looked like on my car installed without the rear stay removed, once you remove the rear stay (5 minute job) you can put the soft top down fully.


Here's what it looks like disassembled (the removable section of the rear stay is still connected to the bottom of the rear stay in this photo)

[Custardtart]

Thanks Dan, no plans for the hardtop just yet so the BD bar looks a good option.
Also hadn’t considered the airbag issue. I’ll probably have to run the standard seats and risk getting stopped when I’m driving to an event.
My car currently has SAAS seats fitted and the airbag light is annoying so cheers for the tip on switching it off.

[Baconterrain]

Brown Davis sell a rollbar with removable rear stays which is the only way to have a removable roll bar which also allows you to use the soft top as well as being the only CAMS compliant removable rollbar I know of so while it is sort of expensive it's your only real option if you want a bolt in cage (https://rollcage.com.au/product/mazda-mx5-nc-soft-top/). The reason they need to put in a removable rear stay and not just put rear stays in lower on the roll bar like you'll see on roll bars from US companies is due to the CAMS regs which require a specific angle as well as specifying the section where the rear stay meets the main part of the cage.

One benefit of the Brown Davis rollbar is that it comes with documentation showing all of the specifications of the rollbars construction which the engineer can have a look at.

If you want to run a hardtop on your NC you need to know that the Brown Davis rollbar will not fit with a hardtop. I learnt this the hard way because I got a carbon hardtop which forced me to sell the Brown Davis rollbar, rip out the soft top and install a weld in half cage.

Regarding a seat I think you will find that no aftermarket fixed back seat will able to be engineered regardless of it's certification because the NC has seat airbags which you are removing by putting aftermarket seats and the authorities don't like airbags being removed. You can get rid of the airbag light no problems with the drivers side light being remove by putting a resistor in the airbag plug and on the passenger side you can put a resistor in the plug as well as cut the weight sensor out of the stock seat and plug it in.

Most seats should fit fine in the NC with either a fixed side mount or sliders unlike the earlier cars and I installed a few different types including a Racetech RT4009W, a Cobra Imola Pro and a Cobra Suzuka pro. I think the max width of seat you can run in terms of the wing width is about 59cm which was the width of the RT4009W I had as that just touched the door.

The photos on the brown davis website are for the NA/NB roll bars but this is what it looked like on my car installed without the rear stay removed, once you remove the rear stay (5 minute job) you can put the soft top down fully.


Here's what it looks like disassembled (the removable section of the rear stay is still connected to the bottom of the rear stay in this photo)

Can you install the roll cage without removing the soft top?

[Dan]

Can you install the roll cage without removing the soft top?

Yeh, you can install the Brown Davis Roll bar without removing the soft top.

It's very simple to do, it uses the standard mounting points of the stock rollbar for the front screws and only requires 4 holes to be drilled to install the bottom section of the rear stays using the included mounting plates.

Once it's installed If you want to put the soft top down you just need to unscrew the rear stays which is a 5 minute job.

[Custardtart]

I now have the BD installed and tbh I never bother with removing the rear stays as you can get the soft top down enough with them in place. Had no probs getting a mod plate for it in Qld and most of the interior plastic trip behind the seats can stay in place if wanted.

[Snowmotion]

If the airbag light bothers you there are write ups about how to cover the led light in the dash with tape so you will not see it illuminated.

[Nuddy]

If the airbag light bothers you there are write ups about how to cover the led light in the dash with tape so you will not see it illuminated.

Or as Dan says above, fit resistors.