Question about FM butterfly brace and road worthiness

[jamsbong]

Hi Fellow mx5 owners,

I have read numerous discussion about the FM brace and how it changes the way the car feels over bumps.
Since getting my NB1 last year, there is only one complaint i had with it. Going over bumps is extremely uncomfortable especially at high speed like 100kmh freeway. Feels like the car wants to fall apart. The only remedy i have at the moment is to reduce speed or avoid the bumps. it feels like i am rallying on dirt road constantly monitoring the surface and dodging bad surface. I have reduced the tire pressure and it helps considerably. But compared that to my previous car, corolla, the mx5 feels really rough.

Now, my question is this. Will installing this brace affect my road worthiness in vicroads? I've asked a local mechanic on it and they replied that my car will not be road worthy after installing the part because holes have to be drilled into the car and may adversely affect the car's stabiliy and thus safety.
Does that mean i can't drive on the road? I can't sell the car? Anyone had this installed? Can you please give advise?

[KevGoat]

Hey there ... welcome

Can't help with the roadworthy question with the braces fitted, but regarding the ride quality, if you can give some more detail of your car's suspension setup and components, there's bound to be advice that could help improve the comfort and probably handling at the same time.

From your explanation it sounds like there are other issues more than just a flexing chassis.

[Steampunk]

.. they replied that my car will not be road worthy after installing the part because holes have to be drilled into the car and may adversely affect the car's stabiliy and thus safety...

Sounds like yet another idiot mechanic.
Does he not realise that the holes are being filled with bolts and nuts and stuff.
you have to drill holes for Rollbars and they get complied everyday, go find a place that does compliance plates, perhaps a 4WD/truck/caravan place, and talk to an ENGINEER instead.

[project.r.racing]

bingo, above post just said it. if you have to drill into the chassis, then it will effect roadworthyness. getting it complied would be a requirement. but there'd be plenty of assessors that you past a chassis bar or frame without a plate.

[sailaholic]

It's only in tho the floor not not any of the rails. And it's obviously a big ass chassis brace. I'd say they are a numpty or going with the safe answer.

[outbreakmonkey]

Sounds more like rooted shockers to me. Either that or you're just used to driving soft shopping trolleys.

[jamsbong]

I think my car is all stock. There may have been some repaired damage done on the left side judging from the different headlamp on left and the fact that it was not installed perfectly.

I have not test drove another nb1 so i am not sure if this is normal.

Btw, thanks all for your response. I will goto a 4WD mechanic and ask the same question.

Finally, anyone doing group buys for the butterfly brace? Should i just get it straight from USA?

[Steampunk]

I have not test drove another nb1 so i am not sure if this is normal.

I will goto a 4WD mechanic and ask the same question.

You do know about the "scuttle shake" on MX-5's don't you? if not then google it.

Don't go talking ANOTHER mechanic, talk to an ENGINEER, world of difference. I mentioned 4WD/truck/caravan places because they do a heap more chassis mods than your usual car places.

[de Bounce]

IMHO start with the basics like tyre pressure and a proper alignment, while it is being aligned ask them to check the shock.
There are a lot of NB8A's that don't have the butterfly brace and appear to travel along quite well

Might be worth dropping into the Garage on a Thursday night.
Let some of the regular MX5 people have a look before blowing your money on a perceived problem.

[KevGoat]

Another consideration to check out the issues with your car's ride is the Pedders suspension test. Although the cost has doubled recently to $28 (can't believe the amazing $14 cost they stuck with for so many years!) I have found it a great source for information on how my suspension components are holding up. They have never pressured me to do any of the work required, though I have often used them and have always been very happy with the quality of their components and services.

I have absolutely no alliance with them, just a very happy customer over many years and many cars.

[93_Clubman]

Dec 2012 Vicroads Roadworthiness Requirements VSI - see page 8:
http://www.vicroads.vic.gov.au/NR/rdonl ... 12_WEB.pdf

Oct 2011 Vicroads modification guide - see page 2, para 4 & page 4, para 9:
http://www.vicroads.vic.gov.au/NR/rdonl ... hicles.pdf

Superseded versions of the above VSIs are near the bottom of this page & might provide more detail as Vicroads appear to be streamlining some newer VSIs:
http://www.vicroads.vic.gov.au/Home/Saf ... mation.htm

[NitroDann]

I bet its a setup issue or worn parts.

that our you are used to driving boats.

Dann

[jamsbong]

IMHO start with the basics like tyre pressure and a proper alignment, while it is being aligned ask them to check the shock.
There are a lot of NB8A's that don't have the butterfly brace and appear to travel along quite well

Might be worth dropping into the Garage on a Thursday night.
Let some of the regular MX5 people have a look before blowing your money on a perceived problem.

This sounds like a good idea. Also, I'm keen to meet other MX5 enthusiast. Where can I meet you ppl?
I live at West Footscray.

[Wivvix]

What you are describing doesn't sound right for an NB.
I'd get things looked at by a mechanic who knows mx5s. See if you can find one through this forum.

If you do decide to go down the FM brace route, I suggest getting the frame rails alone. The butterfly brace helps but it's also a pain and significantly complicates the install, and fitment issues with cats and exhaust pipe.
Aside from that you could also look at the other usual culprits, i.e. wheel bearings, suspension bushings, bent a-arms, tyres, shocks/springs etc.

[sailaholic]

If you only go the rails there is a local Australian made version. Have a look at omgpham.com who is a site sponsor.