mx5cartalk.com

Hi,

I bought my first MX-5 a few months ago. A 1999 Twilight Blue NB, completely stock with low klms and an engine bay you could eat out of...

I have been on a steep learning curve since then as the handling was nowhere near the "riding on rails" experience that so many describe the MX-5 by.

Symptoms - Amazing and secure in a straight line on smooth, flat road with very little to complain about. Cornering to any degree was like steering a boat. On any kind of corrugated surface ( ie most NSW roads ) shuddering, oversteer, very nervous in the rear when cornering and even more so when braking in a corner.

Three different suspension and tyre places checked the car on the hoist and reported that all suspension components where perfectly fine and couldn't figure out why the car behaved like it did.

Endless nights of Google and scouring through forums around the world led me to believe that it was all due to chassis flex. The chassis had become a giant flexing shock absorber along with the driver and passenger.

So, after changing the tyres to Bridgestone Adrenalins (brilliant), bracing the chassis began with the obligatory front tower strut brace. This reduced the oversteer immediately.

I decided to go with a local manufacturer called Ultra Racing who make a full set of braces for the NA. With a slight bit of tweaking they fit the NB and the results are very impressive. http://www.ultraracingaustralia.com/page15.htm

After driving with the upper brace and new tyres for a week or so, I took the NB back to SuziTech http://www.suzitech.com/
to fit the front lower brace


and the lower middle brace


I could feel the difference as I backed the car out of the workshop! Now the MX-5 lives up to it's reputation of precise handling and driver pleasure. The car has it's original shocks, springs and bushes, but suddenly feels stiffer and far more solid. I can feel the suspension working as I drive.

Peter at SuziTech described bracing the chassis to be like laminating timber. A thick piece of timber can flex and eventually warp, but layers of thinner, laminated timber are much stronger and resist greater degrees of flex. I have since added a Style II Stylebar mounted across the seatbelt towers to strengthen the upper middle and relieve some of the shudder in the body and open roof.

I plan to continue onto the rear with a lower control arm brace from Racing Beat that I have on the way from the USA and possibly a rear strut tower brace in the boot.


Just thought I would share the love...

Welcome Ando, Thanks for sharing.
Btw those bars are standard on 2001 NB8B onwards, and you can install them also on to NB8A.
There are some other company that makes similar braces to yours (Autoexe, Cusco) but its quite expensive.
IMO prob the best chassis brace out-there is FM butterfly brace



http://www.flyinmiata.com/index.php?dep ... 20%2090-97

Ando, can you take some photos from ground level, the pics on the site make it looks like it hangs down a bit, even the lower height of the butterfly brace have caught one or two owners.

I'll be interested to see if you notice any difference with the rear lower control arm brace on your NB, they have a bar across that point already.

It's also interesting to see the strut brace was noticeable as there's some others on this forum who think they serve no purpose, I found a difference when I put one on our NB.

I think if your MX-5 was behaving correctly before the strut tower brace, the effect would be minimal. You have to remember that my car was flexing quite a bit, so there was no consistency in the suspension whatsoever. Adding any rigidity began to bring the car back to it's original spec.
I'm pretty sure my NB didn't come out of the factory performing the way I found it, and all I have done has made the chassis stiffer so it can behave like it would have when it was new perhaps.

Even though it has it's stock braces fitted, the extra braces laminate the support and increase the resistance to flex. Any flex will reduce the effectiveness and performance of the suspension. I suppose the strut tower brace would only work under extreme G's in some people's MX-5's as their ride is probably rigid enough for the daily drive etc. Mine wasn't...

Okibi wrote:Ando, can you take some photos from ground level, the pics on the site make it looks like it hangs down a bit, even the lower height of the butterfly brace have caught one or two owners.

I'll be interested to see if you notice any difference with the rear lower control arm brace on your NB, they have a bar across that point already.

It's also interesting to see the strut brace was noticeable as there's some others on this forum who think they serve no purpose, I found a difference when I put one on our NB.

I will post some pics when the rear lower control arm brace goes on. I won't be lowering the car so I haven't worried about ground clearance too much.

The rear lower control arm brace is fixed at 4 points as opposed to the 2 point OEM bars. Hopefully this will keep the geometry between the two rear wheels consistent as the G's kick in and the body rolls above it. I have read that drifters don't brace the rear as it tends to introduce a bit of oversteer, so I will keep my eye on that. Anything I add that introduces a negative influence on the ride will be removed, so these last additions to the rear will be scrutinized heavily.

I kinda like the racing beat rear brace but i think you have to get an alignment again after the install??

The butterfly from FM is a bit too expensive and a bit too much trouble to install (have to drill lots of holes) but probaby works the best.

welcome to the forums

One of the members in our Club had similar symptoms to what you first described with his NB8B with 80,000 on the clock.

After a precision alignment it improved but not to the extent it should have. The suspension was then tested on one of those “shake ’em” up machines to check the shocks and bushes. All seemed to be right but it was decided that the shockies must be almost passed their used by date so in went a new set of Bilsteins and springs.

The problem still existed and in fact got worse. It was decided that the shocks needed to be re-valved so off they came and re-valving was done. Still no great improvement. After much swearing it was decided to go with a known setting and the shocks were re-valved to the same specs as the SE. Still no good. On Club runs he just couldn’t keep up through the corners in fear that the car would skip off the road.

The member by this stage was starting to rip out his hair. He’d dropped big $$$ and still the suspension experts couldn’t work out what was wrong. So one last test was carried out. A hydraulic impact ram was applied to the inside bottom of the front rims to test the lower bushes. As it impacted on the rims it was obvious that the problem had been found. There was outward movement where there should have been none. It took a lot of force to show this up where previous test had failed.

So some more big $$$ were injected into the bushes replacement and the problem was solved. So before you race off and purchase a truck load of braces to fix perceived body flex suspension problems, have your bushes check with this magic hydraulic ram.

Hey Charles.

We checked the lower OEM bushes and found there was a bit of movement as we expected, by you would find this on most OEM MX-5's that drove beautifully. Without changing any bushes (because we did suspect them... ) the lower bracing instantly brought the car back to original performance values where the OEM suspension functions predictably and the car sits flatter through corners and is completely controllable.

Before this, it was like driving a tinny with an outboard motor...

This was also much cheaper and far quicker than changing any bushes. It also gives me a solid platform to address any suspension mods in the future as the shocks and bushes fade. Meanwhile, it darts in and out of corners nice and flat with noticable improvements in braking and ride quality.

Zoom zoom...

Charlie Brown, is the "magic hydraulic ram" a standard procedure and can I get it done any suspension shop"? If not, who did yours? I would think you would need an expert who knows what they are doing. I have no visual flaws on my bushes but suspect they are due for replacement even though I've done only 90K's they are now 19 yrs old and the car does crash over bumps. I have bought a set of bushes and that is my next big job but would like to try this ram test first.

trader wrote:Charlie Brown, is the "magic hydraulic ram" a standard procedure and can I get it done any suspension shop"? If not, who did yours?

I didn't get mine done. NCs never have suspension problems The car mentioned was a NB8B.

The test was done by Wholesale Suspension at Penrith. They weren't the shop that did the original alignment, inspection and shockie installation. The original shop however is a major player in the suspension world and they didn't have the ram.

I believe that Wholesale Suspension normally use the ram to test truck bushes, so I'd expect that your 'run of the mill' shops wouldn't have one unless they specialise in heavy vehicles.

Ando wrote:
We checked the lower OEM bushes and found there was a bit of movement as we expected, by you would find this on most OEM MX-5's that drove beautifully. Without changing any bushes (because we did suspect them... )

There must be some tolerance or range of acceptable movement but I have no idea what it is or at what point you need to change out the bushes. I’m sure most reputable suspension shops would know these figures or maybe someone here could shed some light on this subject?

Ando wrote:

This was also much cheaper and far quicker than changing any bushes.

At some point of time as mentioned above, there has to be too much movement in the bushes that then requires them to be replaced.

If you have the car darting around when cornering, which is not a usual occurrence on a correctly aligned MX-5, then I think that you may just be masking the problem by adding the braces as a fix.

I’m not saying don’t fit braces, because obviously the stiffer the car the easier it is for the wheels to maintain their correct alignment position, just keep in mind that the bushes may need replacing when you go to your next suspension modification.

Hey Ando, sounds like you have been though alot.

Just wondering what alignment settings your are currently running?

I'd be interested to see the final alignment print out too. What tyres did you have on the car before the Bridgestones?

While they add weight i've got a collection of racing beat braces on my car and i'm sure they help.

Did you also check that your sway bars were fine?

Okibi wrote:I'd be interested to see the final alignment print out too. What tyres did you have on the car before the Bridgestones?

While they add weight i've got a collection of racing beat braces on my car and i'm sure they help.

Did you also check that your sway bars were fine?

I expected the bracing to reveal issues with the bushes and the OEM sways etc, but honestly it handles exceptionally well now. Especially considering how farked up it was when I first drove it.

The original tyres were new and awful. Falder or something like that. A chinese copy that looked the goods but had no real performance value. The Bridgestone Adrenalins are a softer compound, asymmetrical tread, performance road tyre that really suits the MX-5.

And Charlie, when I said it was darting in and out of corners after the bracing, I meant that in a positive way! I'm doing the darting, not the car!!

Good to hear another MX5 has been to Peter at SuziTech. I've been meaning to get back there for a while to discuss the next mods, but it's been more than a year between visits
I just keep doing stuff DIY...

marcusus wrote:Good to hear another MX5 has been to Peter at SuziTech. I've been meaning to get back there for a while to discuss the next mods, but it's been more than a year between visits
I just keep doing stuff DIY...

Peter is a top bloke. He did a lot of work to my Swift Gti a few years ago. He is very passionate and commited to doing the best for each customer.

Back to topic.