ruthless_one3k

Hi all, I'm a noob to miatas but very experienced with cars in general. I'm considering selling my skyline and getting a miata to make a track car / weekend car. I see a lot of people make chassis reinforcements to make them even more rigid. Anybody know if they are worth it? Do they add too much weight? Also any advice when looking for a miata?

Track

Sure, for our right speed with similar mods (but a lot more expensive) the NC is faster than the NB and the NA. The NB is probably the better platform of the NA/NB (the same chassis), as Mazda addressed some of the issues present with the NAs chassis.

I track an NB, mostly I love the bang for the buck we get. maintenance is lower and the car is cheaper than practically any other car you can think of.

Chassis rigidity is questionable. Some of it is worth it and some of it isn't. I have had some discussions on this before, but it has been sometime. The aim is to reduce the chassis flex/play due to not having a roof, with that said the best way to do that is by adding bracing as high as you can get it...and connecting the "rear" and "front" chassis. Since our tub is shaped like a U for the most part, you are looking to seal the top of the U pretty much.

Since we lack anything like that other than cage bar doors, anything other than roll bars (which are safety more than rigidity), is usually not very effective. Ultimately you want something to strengthen our torsional rigidity, so cowl shakes and bump unsettling are not the best ways to measure that, which is what most people mention the improvements in.

Frame rails are good if your rails are damaged. I have heard good stuff about the frog arms or whatever (the things that go in the front fender), but I have never tried them. I used to have the boss frog door bars and they did work great, but they came up short (literally and figuratively). Ultimately, you want your door bars to end connected to the rockers or firewall (preferrably the rockers), not the floor pan which is a ------- joke anyway.

tl;dr:
Roll bars are worth it, but more so for safety. caging is worth it. a modified/welded in door bar is worth it. the rest is use at your own discretion.

ruthless_one3k

Thanks, I personally dont find the NC as nice looking as the NA or NB so I will be looking for one of the NA/NB style. i've seen the frog arms online and I guess it does make since to stiffen that portion of the chassis. Most of the reinforcements I would fabricate myself since I have the means to do this. Except the roll bar which will be one of the first mods I purchase because I want it to look and fit perfect. I guess the real question is do they need it? I've never driven a miata but have always heard how well they can handle. I dont want to go throwing extra weight and money at a car that it does not need.

Track

My personal and uneducated opinion on chassis rigidty would say if you want to "fix" our chassis, just cage the car, or go for a half-cage with door bars (proper door bars).

RedTurboMiata

if i was looking to stiffen the chassis, i would go with the boss frog arms, Flyin miata butterfly brace, and a hard dog double diagonal roll bar, sway bars and a good suspension.
edit: i forgot to add door bars.

ruthless_one3k

Thats pretty close to what I was thinking. I would probably start with a butterfly brace and door bars but fabricate them myself, and then buy a roll bar. I would like to hear some feedback from people who have used the frog bars. It makes sense to me from the physics aspect how they could work, but real life experience trumps my physics every time. I really dont want to go adding too much weight to the car if it does pay off in the end.

I see you are from ohio, I'm originally from newark ,OH. That may be where I get a miata from too. I still have family there that could pick one up for me.

RedTurboMiata

if you going to do it yourself make it out of the heavyiest gauge sheet metal possible.

sixshooter

I would get the Hard Dog Hard Core roll bar from Bethania Garage with either the single or double diagonals. I would also buy their door bar kit that is made to work with and tie to the lower front mounts on the rollbar so that it is all tied together. This will make more difference than the butterfly brace. I have heard many times that these door bars are great for chassis rigidity when tied in this way.

I don't know if there is much gain in the frog arms but they aren't terribly expensive or difficult to install.

Just make sure that your Miata has all of the (in some cases optional) factory subframe bracing. If yours isn't equipped with them, you should get them because they do work.

ruthless_one3k

I will probably make everything out of tubing since I have more exp. with it.

Will do. Thanks for all the tips I'll be sure to check for the subframe bracing. As for the door bars I will probably make them myself. I would like to make them connect to the roll bar (hard dog with the double diagonals is my favorite) at least two places on the subframe/rockers and the firewall to link to the strut tower braces.

Of course the biggest problem right now is I need to buy a Miata. I have found a 94' and a 97' locally but I need to sell my skyline before I can register another car in my name, but right now it's too cold to go out and clean it up to get it ready for sale.

sixshooter

I lived in Augsburg for zwei jahre.