Can upgrading safety also improve comfort? | Project Endurance Race Miata

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Update by Tom Suddard to the Mazda Miata project car
Jul 22, 2022

We now had a running, driving LFX-swapped Miata–one with 281 horsepower at the wheels, in fact–but we weren’t quite ready for the track. The next item on our to-do list? Improve our safety gear. Let’s get to work.

I Seat What You Mean

The first item on our upgrade list? That race seat.

We’d previously been racing in a basic Kirkey aluminum seat, but then its cover went up in a ball of fire when we got a little too close with the welder.

We figured we’d take this opportunity to upgrade to a safer, more comfortable seat with a halo, so we started measuring. Putting a halo seat into a Miata is tricky, as both the head restraint and the main hoop often try to occupy the same space,

RaceQuip offers a seat that worked for us. Its FIA-rated composite full containment racing seat stickers for $699.95, and after some careful measuring, we figured we could fit even the large size in our tiny Miata.

For a very reasonable price, this seat should make our car safer and still have plenty of room for our largest drivers. We also ordered a set of RaceQuip aluminum seat brackets, which cost $149.95 each.

Halo seats feature additional structure on both sides of the driver’s head. This will lessen the fatigue of having to hold our head in the turns. However, more importantly, it means more safety in collisions other than direct frontal impacts.

But don’t most accidents occur at different angles?”

Good point–that’s why we ordered this seat for our car.

Ordering the seat was easy enough, and we figured it would be smooth sailing from here forward: Drill a few holes, clip in a race harness, done. Sure, this large seat would be a tight fit, but we should be just barely able to cram it in there.

Making Room

BANG!

That was the sound of our new seat settling into position in our Miata. One problem: That sound came a full six inches above the floor of the car, as the seat interfered with everything. What we thought would be a simple replacement had turned into a massive fabrication task.

What was the seat hitting? First up on the list: Our door bars, which we never loved.

We prefer our door bars to extend away from the driver as much as possible to add side-impact protection, but the cage we inherited with this Miata ran them just inches from our left elbow. (And before you email us, yes: Our Miata’s front down bar is in a less than ideal position. We’ll address that in a future update.) The lower bar was so close that it hit our new seat.

How do you fix this? There’s really only one way: Out with the old and in with the new. We’d need to cut out the old door bars and build better ones from scratch.

After a few hours with a Sawzall and a grinder, we had clean, bare metal and a solid foundation. And after a few test fits and removing the Miata’s OEM side impact protection in the driver’s door, we settled on a design that would gain about four inches of additional room and make plenty of room for our seat and driver.

Where do you buy roll cage tubing? We ordered ours online, buying a 20’ stick for about $300. To save a few hundred bucks on shipping, we had the tube cut to six-foot lengths before shipping. 

The series that we plan to run with allow the OEM side impact bar to be removed, but make sure to read your rulebook(s) before you replicate this move. Note that our design specifically excludes S-bends, too, as those weaken the cage and won’t pass tech for many organizations. After a few evenings bending, tacking, testing and welding, we’d finished our new door bars.

How did we know where to bend our steel? Well, it depends. There are numerous formulas and measuring techniques available online (our Eastwood tubing bender also included a handy booklet) but at the end of the day this kind of project is always going to mean some wasted tube for amateurs like us.

BANG!

Yeah, you didn’t really think it would be that easy, did you? At least the seat made it further into the car this time, now interfering with our main hoop’s mounting plate.

Sigh…

We again broke out the cutoff wheel and the grinder. Our Miata has a dropped driver’s floor to add headroom, and when we originally installed it, we didn’t drop the portion around the cage mounting plate.

We needed a few more inches to fit this seat, so we moved our cage foot’s vertical element further towards the rear of the car and welded in steel plate to fill the gap. Finally, we could install our seat.

BANG!

Seriously?! At least we were close this time, just an inch or so away from the seat’s landing zone.

Clearly, we’d made it far enough to break out the BFH, or big friendly hammer if you’re not a fan of acronyms. Then we absolutely pummeled our poor little Miata’s transmission tunnel until it had a four-inch tear and our seat finally settled into position. We welded up the torn tunnel, bolted the seat down, and moved onto the next problem.

Let’s Install a Race Harness

We’d finally installed our seat, but since we were no longer sitting on the floor, our Miata’s already low harness bar would need to be fixed.

A race harness’s shoulder straps should be level on their way from the driver’s shoulders to their mounting points, so we welded an additional harness bar into our Miata at the proper height. To learn how to properly fit a harness, go read this:

[Strap In: How to Properly Install a Racing Harness]

After one final test-fit, we put the welder away and gave everything a final coat of Gloss Classic Grey spray paint.

Finally, we reinstalled our seat and harness, then topped off our safety system with SFI-approved roll cage padding from Moroso. Our Miata was nearly ready to hit the track, expect for that gaping hole in the hood. We’ll fix that next.

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DaleCarter
DaleCarter GRM+ Memberand New Reader
7/30/22 12:34 a.m.

Moving from one of the nicer Kirkey seats to an ISP containment seat and higher quality harnesses spoiled me. Comfort and safety should make you quicker :-)

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