So I'm planning on welding up some bits of my manifold, and I found these guys: 90 Degree Black Steel Elbow
According to their helpful chat people, they're schedule 40. Is that the wrong metal to make a manifold out of? I'd go with stainless, but I can't back purge, and I've never done SS before (I hear she's fickle).

On a side note, is 1 1/4 big enough for an SR20 T25? I used a calculator a while back and found that the elbows flow more than the head (under flow bench conditions), so in theory I should be fine, right?

 

sch40 mild is fine
1.25 is plenty

 

Local industrial supply house can be a source.

There are head flanges that are made for 1.25 that transition from oval at head to round at elbows / tees.

 

Yeah those are neat.

And for some reason the local places for me were much more expensive than ordering online and shipping. Stupid overpriced CA. And the stupid tax we have

 

Those look exactly like the ones I get from my local plumbing store. They are also about the same price. They will work fine for whatever type of manifold you are trying to build.

 

Thanks guys, I'll order them now. I'll post some pics once I get them jigged and tigged

 

acestainless (now ace race) was the cheapest for me. But that was sch40 304. You'll want to call BMC race and have them custom make you the flange for that size pipe so you dont have to deal with crushing and bs.

 

Do not waste any time or energy dealing with BMC Race. They are slow and expensive. Buy from PRL Motorsports instead. Here is the 1.8 flange, Here is the 1.6 flange. They are half the price that BMC charges, usually in stock and if not they get made quickly, fit on the 1.6 head (BMC holes are off and it physically won't fit without widening the stud holes), and otherwise exactly the same.

 

I actually shot him an email already after I saw someone here get a premium flange that looked really nice. Seems like a small operation he has going on, and I like supporting small business, but I found this: Exhaust Head Flange - Mazda - Mazda Miata 1.6 Exhaust Head Flange and now I hear they don't fit...

My only worry is that I'm using schedule 40 while these might be for sch 10. I doubt a little porting on the inside wall will hurt anything

edit: links are working now

 

Or order a flange from the place I linked to in the post above and save another $20.