DIY Butterfly Brace
 

Well, there is roadwork in my neighborhood.

Idiots dug up the road, and did not bother to build a ramp to make a smooth transition, and clearly lack the brains to mark what they have done.

I was following a truck at slow speed, and suddenly my car became a seesaw... Kinda. All four wheels were making contact with the planet, but barely..

Needles to say, there was some serious damage to the underbody. The chassis rails were badly crushed.

I decided just pulling the rails would not suffice, so I went about building a DIY butterfly brace.

I know FM uses 2.0 mm steel for their setup. I went for 2.5mm steel, and doubled up the steel on either end on both sides for about 8 inches, so I would get some really strong jacking points...

Here's the chassis rail once it has been straightened and undercoating applied:

https://www.miataturbo.net/attachmen...ine=1373754609

Trial fitting the reinforcing rail.

Bent out of 2.5mm steel plate.

I drilled a series of 10mm holes for welding spots. I thought that wopuld be better than just bolting it on.

The inside of the rail was also undercoated to avoid rust.

https://www.miataturbo.net/attachmen...ine=1373754799

Welded in place, end plates and L brackets are also welded.

https://www.miataturbo.net/attachmen...ine=1373754912

Cleaned up welds, applied black body glue to all gaps to ensure crap does not get in there.

https://www.miataturbo.net/attachmen...ine=1373755132

https://www.miataturbo.net/attachmen...ine=1373755132

I also had some bracing cut and bent into a shallow "U" shape.

Cut those to size and trial fit everything.

https://www.miataturbo.net/attachmen...ine=1373755307

https://www.miataturbo.net/attachmen...ine=1373755307

Once that was done, all I had to was to remove the bracing, undercoat everything, and finalize the install.

I also bolted the cross braces together for good measure.

https://www.miataturbo.net/attachmen...ine=1373755493

https://www.miataturbo.net/attachmen...ine=1373755493

I spent just under $25 for ALL the steel, and about $15 for 3 cans of undercoating.
(You thread on a spray gun on the undercoating can and have at it...)

I also found a cool place where they cut and bend steel (up to 10mm thick) to whatever size/shape/angle you can think of, and charge you by the actual square footage. They have very reasonable prices.

I guess a wheel alignment is next after such a "surgery".

And yes, the car feels very solid now.



Please spare no criticism.
I just winged this project, and I would appreciate any input.

Oh, I spoke with the city manager in charge of roadwork, and he said I should send them the bill for the repairs.
That's why I did everything at the Mazda service. I would like them to collect whatever they think is fair from the city. It was my labor, but I took up their space in their shop for this thing.

Very nice project. I have Stein's frame rails from several years ago and they make a difference. The cross bracing is something I haven't done yet.

Nice job - I just did something similar to save the $200+ I would spend on FM butterfly. I do have their SS rail reinforcements, but I wanted some cross bracing. I don't have a welder, so I fastened everything.

Looks awesome. Wish I had a lift and welding ability to do this.

Dang wish I had the skills to pull this off!