Not enough to hold it down? Would explain some of the warping. The first time I welded it I didn't connect it to anything. That warped so much I had to recut the pipes.

That didnt really do dick. I bolted mine to a stock header with every bolt as tight as I fucking could and I was worried that wouldnt be good enough. I also machined a 3/4" think steel plate with both the BP flange and the T25 flange if anyone is interested in buying a pimpy fixture plate for cranking out a lot of these.

It did way more than not bolting it to anything. I'm not saying it was ideal but it was better than nothing. If I do it again I will use that c-channel and bolt to it. It was about 3/4".

It was my first manifold and I learned a lot. I won't build another one without a band saw, fixture to hold the flange, backpurging, and post flow. Also I would go with 1/2" flanges instead of 3/8"

It would keep warpage down if the part you used was able to pull enough heat and not warp.

3/4" plate is nice and would be effective, but unfortunately, its not thick enough to do more than 5 or 6 manifolds before it would need to be surfaced. If you are a decent welder and have a TIG unit that has duty cycle to do 100+ amps non stop... a 3/4" piece will turn into a banana.

FWIW, I use a 2" piece of cold rolled and it gets to be burn your hand hot after welding all of the runners to the head flange, even with the purge gas going through it. The turbo flange gets equally as hot, because its small... but your spending a lot less time on it because its pretty open and easy to weld before you get the rest of the manifold in the way.

With this method, I have had really good luck with welding the flanges and have generally no need to surface the flanges. I do surface them on my belt sander to make totally sure that each product is top of the line, ready to go. Its more of a quality assurance than quality control.

Remove your cylinder head from your car and use that as your heat sink.

A buddy of mine with a really nice CNC machine makes 1/2 flanges.

http://www.mazworx.com/resize/shared...0&bh=550&h=550
http://www.mazworx.com/resize/Shared...0&bh=550&h=550
Mazworx - BP #965515

Mark is a really interesting guy. He carves new RB26 and SR20 blocks out of huge chunks of aluminum with one of his CNC machines (amongst other things).

http://www.mazworx.com/resize/shared...0&bh=550&h=550

For a 1.6?

But wow that is a steal. When I go to 1.8 I know where I'll be getting my flange.

I get very similar flanges from bmcrace.com. Only difference that I can tell is I get them made for schedule 40 pipes.

And made out of 304 stainless instead of mild. They'll also make them for 1.25".

Are you saying BMC does 304 stainless and will do for 1.25 pipe or Steve's guy will?

That is correct. I got my flange from BMC race, had to call to order but 304 and 1.25 sch 40 was no problem.

Get a cylinder head from a junkyard, and use that as your heat sink.

If a flanges is milled for sch. 10, then it'll fit sch. 40 as they are the same OD. Don't worry about the slight ID difference for flow but if you must, a few min with a die grinder will fix that.

That's not as silly, and we only do silly here.

Mention something silly and hope the guy figures out the obvious smarter solution, which ultimately helps his self esteem.

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just finished it

snap ring groove
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assembled
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my vise is a total piece of shit; one of the jaws tries to climb the other when i roll it in one direction, so i can only roll in the other, the jaws are a little wiggly and i have to "steer" the pipe. in a nice vise, i bet it would be solid.

this was my first attmept. you can see how i left a sharp edge on the female die so it left a ridge. it has since been rounded off and the 2nd one came out much better. pics of 2nd attempt were potato.

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woah. Thats brilliant

It works fine only driving one side? Dont all the ones you'd buy have gears connecting them?

the gears provide more positive drive. i have to apply torque to the pipe and the "hand crank" without them. works fine for pipe this size. thicker walls and/or steel would require a set of gears or chain.

Oh yell yeah.
That is awesome!

I think i posted this in my build thread.

Titanium.
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Something new I haven't seen anybody else do on a Miata, but I'm moving more air flow through the Naca ducts in the underbody.

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Here is part 1 of many of making fiberglass parts at work

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