How to get a stiffer Miata

[tor]

I have just bought me a -91 mx5, and I wonder if anyone have ideas how to get it stiffer? I dont want to mount a rollbar. So what do you recomend?

[BoBo]

FM frame rail or full butterfly brace. Also a hardtop would nice, it makes everything quiet and reduces vibrations a lot.

[atank]

I agree with "BoBo" the frame rails / butterfly brace work perfect, a good inexpensive start also would be a rear cockpit brace that was standard equipment on NA8's.

http://home.epix.net/~dppluta/thebrg/oemcockpitbrace.jpg

http://www.topdownmx5.com/images/framerail/100_0556.JPG

http://i.imgur.com/WrwM1.jpg

[kung fu jesus]

Sell it and buy a sedan.


Door bars, bolted down hardtop, fender braces, harness bar, frame rails.

[Phatmiata]

Actually the factory hardtop will tighten up the Miata quite nicely. It also cuts down on road noise, and keeps the car cooler in the summer, warmer in the winter

[treeafodo]

I'm not sure if you'd want to do this or not since you don't want to install a roll bar, but you could stitch weld the chassis. It wouldn't change the appearance of the car at all.

[TimTim]

Sell it and buy a sedan.


Door bars, bolted down hardtop, fender braces, harness bar, frame rails.

I would even argue "in that order". After a test drive in an nb with door bars I remember discussing with KFJ about the very "German" character it gave the miata. Depending on how you "use" the interior, they may not be invasive at all.

Id also add the strut tower brace such as the FM one. It is good/easy to install/affordable. It is very localized in that it stiffens only the front but it is certainly profound in its effect on steering feel and the reduced shimmy associated with worn out stock nas. In contrast the same part installed on the nb had a far less dramatic improvement.

[TimTim]

Forgot to mention, it's a little off-the-beaten-path, but the seam running along the entire door sill (both sides of the car) is easily accessible and can be spot welded with a fairly conservative harbor freight unit. Certainly more of the "diy" route. This is supposed to be one of the best "effort/payoff" portions of the car to spot/seam/stitch weld as it strengthens the central "tub" of the car

[kung fu jesus]

If a strut tower brace is used, a 3 point one would work better than a 2 pt.

[tsingson]

If a strut tower brace is used, a 3 point one would work better than a 2 pt.

But isn't the point where the brace attached to on the firewall area thin metal?


From Flyin' Miata's website:
Some also "triangulate" to the thin metal at the top of the firewall, but there`s no structure to tie into there.

I was just curious because both make sense.

[kung fu jesus]

http://www.flyinmiata.com/tech/seamweld.php

[Dandy]

The early NA's benefit the most from stiffening the chassis. Mazda sacrificed some rigidity for the sake of lightness and maybe cost in the early NA's. The simplest and probably cheapest of these braces is the rear subframe brace. This brace was added by Mazda starting with '93 models. I would add this brace first out of general principle because it just belongs.

Another vote for frame rails here. Installation is more complicated but they have the additional benefit of protecting the factory rails from bumps and scrapes and also provide a solid jacking point. This is important because if the frame rails get misshapen, your already floppy Miata can feel even floppier.

Front fender braces are also a more complicated install but will help keep the front end from twisting and will help reduce cowl shake.

While not a direct stiffening component, 20+ year old Miatas will benefit from new bushings to allow suspension components to operate more precisely.

An early NA can pretty much benefit from every single bar or brace ever made but after the items I've mentioned I think you have to consider cost and the additional weight penalty vs. benefit.

[atank]

Carbing Three Point.........
http://i.imgur.com/hx2pIQS.jpg
http://i.imgur.com/9X7L6NS.jpg
http://i.imgur.com/WhYeAhK.jpg
http://i.imgur.com/oYov7ft.jpg
http://i.imgur.com/r1vfy94.jpg

Carbing Rear Brace installed, with spare tire re-locator:

http://i.imgur.com/DVxLdHT.jpg (http://imgur.com/DVxLdHT)

http://i.imgur.com/HpMcADo.jpg (http://imgur.com/HpMcADo)

http://i.imgur.com/FtDZOuJ.jpg (http://imgur.com/FtDZOuJ)

Vintage Fujita Engineering Cockpit Brace...................

http://i.imgur.com/18jCXiF.jpg (http://imgur.com/18jCXiF)

http://i.imgur.com/Pv2Mx7L.jpg (http://imgur.com/Pv2Mx7L)

http://i.imgur.com/0HCc269.jpg (http://imgur.com/0HCc269)

[etikoner]

Damn, that's some nice monkey bars you have there, haha.

I installed a 99 sport STB (Shock tower bar) on my car, and the front end of my car had reduced NVH.

[Ciotti]

I've had my Carbing STB on and off and on and off my 99 NB and I haven't felt any difference in turn in, NVH, or anything else for that matter which makes sense because none of the load from the suspension goes into the strut towers where it attaches.

[kung fu jesus]

A few observations...STBs are more helpful if they are fixed with no pivot points. I can certainly understand the reasons why people wouldn't want a rollbar, however each Miata I have owned has one for chassis rigidity. I also added bolt-in doorbars, which were the greatest addition to reduce NVH and additional rigidity. This was especially true in the NA.

Seam welding is the most laborious method, but least intrusive. It still won't add as much rigidity as a triangulated system. I'm not an engineer, though.