Chassis Bracing

[PUR157]

So I have a tired old NA that I was wanting to brace up abit, I was wondering what the collective experience on chassis bracing via Front/Rear strut and/or Chassis braces were?

I have a friend that had a Type R Integra and he braced the crap out of it (front mid and rear) and he succeeded in making an already knife edge car even more nervous...
For me the intent is more towards a chassis refresher rather than turning it into a road racer.

Would the Front and Rear combo end up being overkill for the MX5 too?

I'm on Tein Basics

I've also considered the Ultra Racing under chassis brace that's been mentioned a couple of times around here. I don't really like the idea of the FM Frame rails.

All three? one or the other? a combination of the two?
Random thoughts?

[93_Clubman]

front tower brace only makes a slight difference, but isn't really expensive - might be worth considering a decent rollbar if you don't already have one, as it at least serves a dual purpose.

[broady]

I don't really like the idea of the FM Frame rails.

Why's this? Supposedly one of the most effective ways of getting back some stiffness to the chassis. I suppose the work to get it in is quite substantial though.

Also maybe consider a rollbar if you don't have one already.

Some other options:
Cusco side braces
Boss frog "arms"
Replacing bushes

[Wivvix]

The frame rails ought to improve chassis torsional rigidity by about 33%, so on a tired miata take it back to showroom floor stiffness.

I actually like the idea of the frame rails and butterfly brace.
It's stainless steel so it won't rust easily.
It may weigh 15kg or so, but it's all low centre of gravity, under the car.
The weight is distributed over quite a large area and uniformly to both sides of the car.
The impact on suspension characteristics should therefore also be fairly uniform.

Changing the resonant frequency of the chassis should also help eliminate NVH and/or tyre-related vibrations.

Compare that with the quality, uniformity, weight properties, centre of gravity or attachment methods of any other reinforcing product on the market, and the frame rails begin to look very attractive.
Personally the only other thing i'd even consider is a torsion box roll-bar, and even that has its downsides.

Just my 2c.

[Guran]

My understanding is that strut braces do very little for NAs, so skip that. Your best bet would be to replace all the suspension bushes.

[fattima]

On my NA6 the biggest difference came from adding a roll bar. I purchased a NA8 already fitted with the FM butterfly brace and it really stiffens the car up. I really like how it makes the car feel, very solid like a car with a roll cage.

[PUR157]

I suppose the work to get it in is quite substantial though.

This ^ and the pockets aren't quite deep enough...

I do have a BD installed tho, but my car may have had other problems that didn't allow it to fully capitalise...

Bushes is a good idea actually.... I can only guess that I'm on the originals

[broady]

Initial verdict (a bit of a squirt around, albeit in the wet): not worth it if you're after a stiffer ride. I do feel the front end being slightly stiffer but I think there's definitely other things that would be more effective (underbody bracing etc)

[Rob E]

NA6 or NA8?

[Guran]

Quote from page 50 of Mazda Miata Performance Handbook:

"The author asked one of Mazda's top suspension engineers what would be the first thing he'd improve on a Miata with 60,000 miles. His answer was quick and short: Replace all the suspension bushings."

[93_Clubman]

NA6 or NA8?

NA8 Clubman

[Wivvix]

# (Durometer)
88 Energy Suspension front lower and all rear control arm
95 Energy Suspension front upper, sway bar and differential mount
80 Super Pro control arm, all
65 Polybush blue- soft
75 Polybush orange- sport
? Powerflex
70 Maruha rubber
55-65 Mazda Comp rubber

Rubber OEM is thought to be somewhere around 50'ish or below.
The question you have to ask yourself then is how hard are old rubber bushings, and do you want bushings that are twice as stiff.
Personally I say no, which is why I haven't done bushings yet either on my 190k NA8. It needs them, but rubber doesn't come cheap.

[Rob E]

NA6 or NA8?

NA8 Clubman

ok, so you have the front lower cross, and the rear box brace standard. You have a BD bar. That leaves front and rear STB that will do very little, or Ultra Braces, which are an extension of your stock bracing (more mounting points). The elephant in the closet is the FM Butterfly however, and really given where your car is now the only brace i would bother with. Anything else, and you are just wasting money that could be better used elsewhere

[93_Clubman]

# (Durometer)
88 Energy Suspension front lower and all rear control arm
95 Energy Suspension front upper, sway bar and differential mount
80 Super Pro control arm, all
65 Polybush blue- soft
75 Polybush orange- sport
? Powerflex
70 Maruha rubber
55-65 Mazda Comp rubber

Rubber OEM is thought to be somewhere around 50'ish or below.
The question you have to ask yourself then is how hard are old rubber bushings, and do you want bushings that are twice as stiff.
Personally I say no, which is why I haven't done bushings yet either on my 190k NA8. It needs them, but rubber doesn't come cheap.

Useful comparison - good post.

[Rob E]

why would you think that dried up old bushings are still equivalent to new OEM 50 durometer from a compliance standpoint?