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View Full Version : I want to make my own downpipe...



Subliminal
01-17-2007, 10:56 AM
...but I'm not sure on a few of the parts.

The bends and stuff, I'm not too worried about, but the part with the donut that goes into the sv, that's got me a little confused.

Has anyone made their own downpipes? If so, how'd you do it?

An inquiring mind wants to know.

tryingbe
01-17-2007, 11:27 AM
I made mine, but I have access to a a welder and a press.

Subliminal
01-17-2007, 11:37 AM
I also have access to a welder, and I'm sure I could do a little pressing with the tools I've got as well. Just need a little 411 on the part that connects to the sv.

DodgeZ
01-17-2007, 12:00 PM
I think you can just weld a stop ring on.

altered7151
01-17-2007, 12:18 PM
I would just buy the donut then weld on a stop ring like Kevin said. If I may make a suggestion, it you're doing a new downpipe, make up a new swingvalve and use a v-band clamp. I have one on my car and its leaps and bounds easier to get off over the goofy bolt and spring setup.

Subliminal
01-17-2007, 12:19 PM
Could you elaborate on that, please? :)

I looked at your post and see that you did a really nice job on the sv, but that you had to use an external wastegate, which was probably more than a few $$$, eh?

tryingbe
01-17-2007, 12:22 PM
Stuff you'll need.

A welder
A press
A flare out tool
A 3 inch donut from TU
A 2.5 inch exhaust flange from TU
3 inch straight pipes
3 inch 180 bend pipes


Alright, you cut a 3 inch straight pipe as long as length of first section of the downpipe, flare it out using a press. Then you use the press again to press the flared end FLAT. You just now made the lip for yoru exhaust donut to sit on. The lip only need to be 1/4 - 1/2 inch

So from this

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to

\ /
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to
_ _
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Then, you cut another 3 inch pipe, 1-2 inch of so in length, you place it on top of the piece you just press flat and weld them togather from the INSIDE.

Now, you take that 2.5 inch exhaust flare you bought from TU and bore it out to 3 inch. You just cut the 180 bends and weld to your new downpipe from there.

mcsvt
01-17-2007, 12:25 PM
I also support the use of a v-band. I bought a custom 3" SV that was made with a v-band. There are pics in my gallery of the SV. It is extremely easy to get off compared to the stock setup.

altered7151
01-17-2007, 06:27 PM
Could you elaborate on that, please? :)

I looked at your post and see that you did a really nice job on the sv, but that you had to use an external wastegate, which was probably more than a few $$$, eh?

Yeah I went with the external setup, wasn't too pricey got the wastegate for 180 then just fabbed up everything myself. You dont have to go that route though, you could take a stock swingvalve and cut off the stock donut flange, then have one side of the v-band coupler welded to the swingvalve.

Tony Hanna
01-19-2007, 12:39 PM
I've thought it out, but haven't actually tried to build it yet.
Here's how I was planning to do it.
I wanted to start with the downpipe section of a 3" JRB style exhaust. Since they're made a little short I planned to weld an extension to the end to make it the same length as a stock downpipe.
Once that's done, enlarge a 2.5" flange with a die grinder to fit over the 3" pipe.
Next, make a stop ring like Kevin mentioned. What I had in mind for that was basically torch cutting a washer with a 3" hole out of a piece of plate, positioning it so that the end of the pipe comes through just far enough to be flush with the end of a 3" donut gasket and welding it to the pipe on the bottom (flange side).
That's about it. Since I haven't actually tried it, there may be some problems that I haven't considered, but if it goes right, it should be quick and simple to build.

phaxtris
01-20-2007, 06:22 PM
sounds like a pretty solid idea to me

Tony Hanna
01-27-2007, 09:24 AM
sounds like a pretty solid idea to me

Thanks!
Who knows, one of these days I may even get around to trying it. If it works, I'll be sure and post about it with pics.:)