Roll bar or chassis brace?

sweep77 · Postby **sweep77** » Sun Nov 18, 2012 8:55 am

Hey guys, I'm thinking of either getting a rollbar or butterfly brace to strengthen up my nb8a. Over rough roads my car seems to have an annoying amount of shaking which may be just normal for an nb as I've only had an na8 before which had the seatbelt brace but never seemed to shake as much as this nb. I thought maybe the shocks are bad but they seem firm enough. Maybe it's just old bushings? Cars only done 80k though. Chassis rails seem in good nic with only 1 slight dint from bad jacking. Maybe just a seatbelt brace would be enough? Thoughts?

rascal · Postby **rascal** » Sun Nov 18, 2012 9:30 am

sweep77 wrote:Hey guys, I'm thinking of either getting a rollbar or butterfly brace to strengthen up my nb8a. Over rough roads my car seems to have an annoying amount of shaking which may be just normal for an nb as I've only had an na8 before which had the seatbelt brace but never seemed to shake as much as this nb. I thought maybe the shocks are bad but they seem firm enough. Maybe it's just old bushings? Cars only done 80k though. Chassis rails seem in good nic with only 1 slight dint from bad jacking. Maybe just a seatbelt brace would be enough? Thoughts?

Personally I'd go roll bar well before butterfly brace.
You gain rollover protection as a bonus..

plohl · Postby **plohl** » Sun Nov 18, 2012 9:47 am

roll bar.

Not a BD one.

sweep77 · Postby **sweep77** » Sun Nov 18, 2012 10:04 am

Why not a bd one? What do people prefer?

Hjt · Postby **Hjt** » Sun Nov 18, 2012 10:14 am

If you want to improve the shaking a roll bar will help, but new bushings will improve overall ride quality.

mgnovenie · Postby **mgnovenie** » Sun Nov 18, 2012 10:22 am

sweep77 wrote:Why not a bd one? What do people prefer?

Yeah, I'd be interested to know why not a BD one? They seem quite popular.

zephyrus17 · Postby **zephyrus17** » Sun Nov 18, 2012 11:00 am

I went with the butterfly brace, with the idea that it's an 'unseen' bonus. It doesn't affect visibility and protects the underside of the car. The moment I got the butterfly brace install, I knew the difference instantly when I sat down! I'm in the process of getting a roll bar too, anyway.

I, too, am curious as to why not a BD? Do tell!

davekmoore · Postby **davekmoore** » Sun Nov 18, 2012 6:33 pm

Maybe drive other NBs and/or get a professional opinion on your shockers, bushes etc before jumping in with anything else?

superfluous2 · Postby **superfluous2** » Sun Nov 18, 2012 9:36 pm

plohl wrote:Not a BD one.

I'm guessing because the BD (Brown Davis) one doesn't have the 'torque box' that the MX5 Plus bar has, as OP was asking about additional bracing.

Compare:
http://www.mx5mania.com.au/images/produ ... bdbar3.gif
^ Brown Davis

http://i230.photobucket.com/albums/ee30 ... 008057.jpg
^ MX5 Plus

The BD one doesn't have the lower horizontal brace that goes between the seatbelt towers (MX5 Plus bar does).

I have an MX5 Plus bar (fitting it tomorrow), and I've dríven a NB with one installed, and the added stiffness is quite noticeable.

Lokiel · Postby **Lokiel** » Sun Nov 18, 2012 10:36 pm

I have an SE which has the most OEM bracing of all NBs and the MX5 Plus Twin-hoop roll bar with integrated torque box made a significant difference to chassis-twist stiffness, the car felt different as soon as I turned onto the main road from MX5 Plus (at their original location) and that was at low speed.

I've since added FM frame rails and Boss Frog Frog Arms but neither felt as dramaticalyy different as the roll bar.

- get the roll bar.

Hjt · Postby **Hjt** » Sun Nov 18, 2012 11:14 pm

Placebo

http://en.wikipedia.org/wiki/Placebo

I believe these options won't fix your problem, I would love proof otherwise.

I think you have another underlying issue that needs fixing.

lightyear · Postby **lightyear** » Mon Nov 19, 2012 8:04 am

You guys that sit in a car and notice a difference by throwing on a roll bar are, ummm, well. Put it this way, that is a very strong part of the car. Tell me what the roll bar is doing to stiffen anything except what is between your legs?

To me it's like throwing on a noisy muffler, and claiming you can feel the difference in power.

Why don't you do an easy test. Jack up the corner of the car, measure the twist with and without the roll bar. Free fastbacky to the winner.

lee · Postby **lee** » Mon Nov 19, 2012 8:23 am

lightyear wrote:Why don't you do an easy test. Jack up the corner of the car, measure the twist with and without the roll bar. Free fastbacky to the winner.

That'd be a really interesting test to perform. If I feel inspired during the summer, I'll see if I can find some laser deflection things and test it out. I could also test out various under body braces as well

Apu · Postby **Apu** » Mon Nov 19, 2012 8:27 am

I'm no engineer but am inclined to agree with Lightyear. I fail to see how a roll bar will reduce twist and chassis flex.

I bought my MX5 Plus twin hoop roll bar for extra protection in a roll over...but am unsure as to how much protection it will give as there isn't a whole heap of clearance. That said, some protection is better than no protection.

91 Malibu · Postby **91 Malibu** » Mon Nov 19, 2012 8:49 am

lee wrote:
lightyear wrote:Why don't you do an easy test. Jack up the corner of the car, measure the twist with and without the roll bar. Free fastbacky to the winner.

That'd be a really interesting test to perform. If I feel inspired during the summer, I'll see if I can find some laser deflection things and test it out. I could also test out various under body braces as well

I would be intersted in this experiment too, My car currently has no extra bracing or a roll bar, so if you want a car that has nothing added as a test car you can use mine.It may save a heap of time removing anything from your car to start with.