evolution of bracing on the mx5

Fatty · Postby **Fatty** » Thu May 01, 2008 10:13 pm

in recent times i've asked a few questions along these lines...

i'm interested in seeing diagrams of the evolution of bracing / stiffening of the mx5 chassis thru the na / nb series. people have mentioned books that show pictures but i have yet to see a definitive online resource showing the improvements made over the years... eg the little braces inside the cabin on the transmission tunnel , the spider web box thingo on the nb8b etc etc.

so i would be keen to see any scans / diagrams showing bracing of different models , cheers.

Garry · Postby **Garry** » Fri May 02, 2008 9:34 am

the spider web box thingo on the nb8b

Whats this? I've never heard of it.

Matty · Postby **Matty** » Fri May 02, 2008 10:34 am

You can probably find some pics on the big forum but the evolution is something like:

1989: nothin
1991: rear subframe lateral bar
1993 (NA8): rear subframe longitudinal
(not sure when the front subframe lateral bar came in)
1998 (NB): lots of welded in chassis gussets, redesigned front lateral brace. (I have pics in a book)
2001 (NB-F): spider-web (the extensive stamped sheet metal brace underneath)

manga_blue · Postby **manga_blue** » Fri May 02, 2008 2:31 pm

On my '95 NA8 there are the rear subframe lateral and longitudinals (all in one welded U-shaped piece) and the front subframe lateral bar, plus of course the seat belt tower brace bar which runs across behind the seats.

blehbear · Postby **blehbear** » Fri May 02, 2008 7:11 pm

Hmm interesting. Can anyone post pics of the evolution?

Postby **Okibi** » Fri May 02, 2008 7:41 pm

Matty wrote:..1998 (NB): lots of welded in chassis gussets, redesigned front lateral brace. (I have pics in a book)..

I think they're the same as in the bottom left of this page

http://www.mx5club.com.au/images/mutton_dressed_as_lamb/7.jpg

Fatty · Postby **Fatty** » Fri May 02, 2008 7:48 pm

ooh nice pic okibi! got a hi res version anywhere???

Fatty · Postby **Fatty** » Fri May 02, 2008 7:51 pm

thanks matty, manga for the input.

Postby **Boyracer** » Fri May 09, 2008 9:57 am

These are all the braces I had to remove to fit exhaust on SE...the silver looking one is more of a heat sheild.

blackster · Postby **blackster** » Fri May 09, 2008 10:11 am

Too add onto Boyracer's pics, this is what it looks like under the car.

jules · Postby **jules** » Fri May 09, 2008 10:31 am

Man, that's a lot of braces..

Jules

Fatty · Postby **Fatty** » Fri May 09, 2008 11:03 am

excelleny pics guys. thanks heaps.

AB7 · Postby **AB7** » Fri May 09, 2008 11:33 am

That silver looking heatshiled/ undertray is only for SE.

I think the spider web thingy also looks different to NB8B

Garry · Postby **Garry** » Fri May 09, 2008 12:31 pm

I think the spider web thingy also looks different to NB8B

It looks the same as mine.

The NB8B also used thicker gauge steel in crucial areas through the body and rumour has it that the SE has some extra reinforcing around the front of the boot opening.

Man, that's a lot of braces..

All that and it still jiggles :frown:

I was reading a technical paper online once presented by Mazda about the things they did to the NC to stiffen it up. Big gains were made from the added longitudinal braces on the floor pan. Increases in torsional rigidity were gained by tying the door pillars together with the box brace that holds the style bar and adding the centre cross brace under the car. As far as Mazda were concerned the NB8B/C was the stiffest they could make the old chassis without adding a lot of extra weight for small returns. I tried searching for the article again but I cant find it. It was quite interesting.

manga_blue · Postby **manga_blue** » Fri May 09, 2008 1:45 pm

Here's an NA8 with an FM butterfly brace added in the middle. It shows the piece across the back of the front subfame and the 3 piece U-shaped thingy across the rear floor and rear subframe.