Butterfly Brace vs Seam Welding

I have money to one or the other. Just for clarity I only plan on welding the door seams and I already have frame rails.

Oh I have a 90 Miata.

Thanks and junk:-)

Butterfly. It addresses a much weaker part of the car.

I would say it depends on your plans with the car.

I just took off my butterfly brace because the points hit isn't worth it for NASA TT. Just a street or HPDE car. Then I'd say it's totally worth it.

To me seam welding is something you do to the car along with a cage.

It is for the street. Thx for the input!

I'd definitely go for it then. Make sure to get a helping hand and a good drill bit.

I would also assemble the middle butterfly section before lifting it up to attach to the framerails.

Keith, What will I need to do to work around the stock 1990 exhaust?

Creativity and a grinder. It's been a while since I tried, but I think fresh exhaust hangers and motor mounts will go a long way too.

What about swapping to a different system?

Sultan wrote: What about swapping to a different system?

Aftermarket header/test pipe eliminate the interference.

Actually, aftermarket cat and header will also solve the problem. That's why we didn't spot it in the design phase. It's amazing how many 20-year-old Miatas still have their original exhaust system.

Hmm. Sounds like you need an FMII and their 3" exhaust to make the butterfly fit.

You're welcome.

Keith would this system work, "1990-97 Flyin` Miata stainless steel exhaust"?

Nope, you'd want the Racing Beat header and FM catalytic converter. The rest of the exhaust is out of reach of the problem.

The most fun option would be a header/cat/exhaust package
http://www.flyinmiata.com/index.php?stocknumber=06-01000

Is a new header necessary if one has the FM cat?

Because if it is that means I get to work on the honey do list this weekend rather than fitting the butterfly brace.

It's possible to fit the butterfly over a stock header and cat. I've done it. But it involves some problem solving skills, which is why we usually just say "no".

If you want a guaranteed no-hassle fit, you'll want a new header and a new cat. If you're able to deal with things, I think the cat is the bigger problem and you just need to take the heatshield off the header. It's been a while.

Well, I have the FM cat + catback exhaust. I guess if I have the time this weekend I'll try, otherwise I'll solve the cat + header fit issues first and then slap on the brace.

Keith does it have to be a RB header? FleaBag has headers for must less. I know you get what you pay for yet I don't have a lot to put towards this. Thanks!

I certainly hope it doesn't have to be an RB header, if it does I have a problem (I have a Maxim Works header).

If I understand Keith's comment correctly the problem is the outside diameter of the header downpipe, which is bigger on the OEM header because of the heat shield (which pretty much all aftermarket headers do not have). That said, I'd try to find a decent used header, unless you like having grief from parts that don't fit that well out of the box and make you wonder if the people who made the part have ever seen the car it goes on.