Miata specific fabrication info
 

So I finally got my welder back and I have been looking into various fabrication techniques/best practices.

It seems the rest of the world has this fabrication stuff down, puts even "the best" set ups here to shame. Everyone here thinks you should build a sch 40 inconel manifold that has a perfectly straight down pipe. The rest of the world isn't so concerned.

Is it just a case of sophomoric carport "engineering"? Or, does everyone else's setup fail every 1000 miles?

Do manifolds crack on the bp due to more vibration and heat and therefore need to be overbuilt, or do we just follow the leader?

I read this twice and I'm still not sure what you're asking

Inconel studs are suggested mostly for track cars. Not sure they are as significant for most other builds. If you are planning a ludicrous build, they are probably worth it, atleast for peace of mind. We are probably above average in the number of members who participate in motorsports compared to other forums.

Most people here are very performance centric. Definitely function over everything (at a budget). You will see more people concerned about getting the most out of parts than getting something that works ok and looks nice.

Its not necessarily that log manifolds fall apart or anything, but we definitely have a lot of engineering minded members. Lots of people still use non-tubular manifolds here, I think Luke posted in his build thread about his log manifold. Also, can't remember the username, but I saw a pretty nice build earlier with relatively average turbo parts.

BPs are not the smoothest most advanced motors, but they do fine overall i would say. Especially for the money investment.

These engines suffer from some sort of resonance issue at high rpm, this cracks manifolds.

That being said, most of the shit being built by super baller fabricators to go on so-called race cars would actually fail if it the car was ever abused in the way that a MTnet user abuses their Miata out on the track. On the internet its easy to come to the conclusion that there are numerous super high quality manifolds out there for every car under the sun. In reality, its not really true.
Even on smooth running Hondas Ive seen a lot of baller manifold crack on the street. These manifolds couldnt hold up on a road course on a Honda engine, let alone a BP vibrating like hell at 7k rpm.

Speedhunters isnt reference material on real race cars. Go out to the track and see what needs to be done for a real race car to last and you will not see a lot of pretty welding and thin-walled stainless steel sculptures. You will see heavy duty shit with bracing on top of bracing and its fucking ugly.

+1 to what Full Tilt said

BP's are not power monsters. They are old tech engines that are durable but don't make any crazy power. So they need all the help they can get. So people upgrade the IM and make really well flowing turbo manifolds as well. BP's also vibrate like crazy, which tends to destroy manifolds way quicker than most other engines. So overbuilding and over-engineering is almost mandatory for track miata's.

It's not my intention to shit on anyone's specific setup. I am looking for discussion from those who actually build parts.

I know SEMA cars probably wouldn't even run, let alone make it around a track. But here the rules are written by those who don't weld, and propagated by those who have never seen a track. My goal is to elevate the fabrication section on here, I know there are great fabricators who have miatas but never post here.

Real race cars aren't unicorns, it isn't so difficult to find them and see what they have. We have one of the best ms forums out there and it would be great to see the same for fab work.

There is a lot of DYI custom work on this thread, there are actually many members that like to make parts, i am one of them.
https://www.miataturbo.net/showthrea...=69633&page=31

Rules? What rules? And how do you do it differently?

Yes, Tim. I'm sure he's willing to give you welding lessons, lol.

Usually its better to "elevate the game" first, then talk about it later.

Hows this: you make some impressive parts then come back and talk down to those that don't fabricate or see the race track. Because right now, you're all talk.

Protip: Hardparking isn't motorsport.

Dann

+1 million. Haven't seen him post in the race prep subforum yet...

Oh lordy, this hasn't gone well. It's probably too late to get this back on track. Eh, some days just don't go as planned.

Turbotim and dann, your work is very good.

:hustler:


:cjerk:

to the last question:
From the time I have been in the Miata scene- its follow the leader.

Read back threads to about 4-5 years ago. You will see everyone saying "cast manifolds if you want reliability" go about 3-4 years ago from now and you will see Turbotim offering tubular manifolds and everyone went to that, then Vband manifolds were cool around then because no hardware failures, then people with bolted turbos upgraded to Inconel hardware, etc... its a really trendy car scene.


I don't think that there are really any issues with well fabricated systems, you don't need crazy materials or unreal thick walls.


I use schedule 10 for all of my manifolds because it seems to be a good middle ground between weight and reliability without going to an ultra high grade 321 that no one with a Miata would be willing to pay for.... there might be 3 or 4 people out there that might be willing to spend $1,500 to $2,000 for a manifold but Im guessing it wont be a hot sale.

Most of those things you talked about were things that were only discovered in the last 4-6 years in the miata world. Up until Savington/Hustler/a few others started stretching studs while on track conventional wisdom was that yes cast manifolds where were you go for reliability. Once track people got to the point where a cast manifold and stock studs no longer worked they started looking for solutions. The Tial V-Bands happened to be the solution that was out at the time. So the track junkies jumped on that band wagon. TurboTim just happened to be in a perfect spot to be one of the few guys known to make good custom manifolds when V-bands were first appearing. So everyone went to him to get the manifolds made. Savington then started working on the Inconel studs. Once he had a formula for ones that would work and not stretch people went back to those, because it is far cheaper then a V-Band setup. So yes there are some trends, but they are trends of what works on a race track. As things break and solutions are found the track junkies tend to move towards those solutions. On mt.net the track junkies just happen to sway the rest of the site heavily.

because of course, all car problems are worked out from day one of release. :jerkit:

Using sch 10 304 stainless on a tubular manifold is a bit of a stretch on a miata, sch 10 mild probably a better idea. And its certainly fine for logs. I even expect my sch40 304 manifold to crack in a few years based on my computer sims. But by then I should be ready for manifold v2 from sch10 or 16ga 321 stainless or inconel to cut weight. The vibration combined with the heat and the packaging in the engine bay is the biggest problem. The vibes are awful on the b engines. The packaging is the worst for making a strong manifold. On any car building a tubular manifold that is going to withstand pulling 1.2+gs lap after lap with 1600*F gases flowing through it sometimes partially on fire with a 20 pound weight hanging off the end and bolted to a big vibrating thing is very difficult. You either massively over build it or you spend weeks doing advanced vibration and thermal loading FEA to determine the proper spots to brace. Put the bracing in the wrong spot and you can make the manifold fail sooner than it would have without bracing.

brace your downpipe and add a flex bellow to the exhaust. it reduces a lot of stress and your shit lasts a lot longer. if you run without a flex bellow of some sort your shits going to crack with haste. I use flexes on all of my kits since I warranty my manifolds for craftsmanship... as long as someone doesn't modify it.

I wasnt even including the issues the downpipe and the rest of the exhaust add into the equation.