so i should buy pre bent pipes and than cut accordingly than have my neighbor tack/weld or take to a shop?

 

Right. I think.

You want to buy "j-bends" which are mandrel bent sections in 180 degrees or whatever. Get at least 2.25" or larger in diameter in whatever material you like. Mild steel is cheaper than stainless. You determine how much angle you need and cut it at that angle with the chop saw mentioned above (or hack saw/sawzall/dremel/rabbid woodchuck/etc). J-bends normally also have straight sections to use if you need any straight in your downpipe, which you will need especially when you get down around the side of the trans. Mark the bends at the correct locations with either sharpie, grind marks, or tack them with a MIG (easy) or TIG (harder). Bring the tacked downpipe to someone who will weld the rest of it together.

Sounds simple.

Got it?

Post pics when you are done.

 

Okay, if i can't get it tacked can i just mark which piece goes where and just have it welded? Will do with the pictures. Okay so i will buy J bends as opposed to straights 45 and 90's

Also, do i NEED Flex bellows? Or is my downpipe possible without it? What is the use of one?

 

the miata doesn't need a flex really.

 

it makes install easier and reduces vibration and strain on the manifold i like having one but it is not neccessary. L/k to close together

 

What's a manifikd??? Can I get one

 

Same here. I didn't have one on my GReddy setup and never had a problem, but have used them on all the kit's I've built...just cause I guess.

 

Check out this link. Guy did a writeup on him building his down 3" downpipe for his HKS mani. Check it out and buy the appropriate bends accordingly.
http://www.cardomain.com/ride/575068/1

 

cashing 1200 paycheck tomorrow, will have some money to do something.

 

nice
the car domain site has alot of info for you tom. check it out it is vague but shows the general idea with pics.

 

I thought I would throw in my $.02 since I just made my DP from a J-bend.

I bought the run-o-the-mill T3 flange, started with a short 90 off the flange, cut pie wedges out of the J-bend with a sawzall, tacked them in place one-by-one untill all 7 wedges made a flawless pipe down to the bracket that's off the bell housing. I welded my own bracket to the DP at that point leaving 1.5" lenght aimed towards the cat. I used a 3" flex coupling here so the rest of the exhaust swinging around didn't pull on the turbo. I bite the bullet and spent $450 on a nice REAL mig welder (not a wire feed flux-core crap one). That welder has paid for itself 10x over with all the little projects I've done for friends. Made a nice gokart for the kid too. =)

Since you don't have a welder you could -try- this.

DP Write-up!!!

Figure out your first piece off your outlet flange and get it generally aimed where you want to go. If you can, get this tacked on the flange. Then start with your wedges. Using a sharpie marker draw a line across the seam, remove the DP, line up your marks, and duct-tape the piece in place by taping all the way around the seam. Try to keep your gaps under 1/8". As a welder, I hate filling holes. =) Continue to do this untill your 'completed' DP is how you like it. Take that to your welder buddy and cut slits in the duct-tape so it can be tack welded. Before you finish welding it you may want to test fit the DP again to make sure nothing shifted. Once you know all is well, take off the rest of the tape and complete the welding.

I had my DP on and off the car at least 2 dozen times (It's made out of 8 pieces.) making sure it could be removed and installed without removing the turbo or anything else that didn't have to do with the exhaust. That's -proper- design imo.

Good luck!