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DIY Turbo Discussion greddy on a 1.8? homebrew kit?

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Old 05-12-2008, 01:11 AM   #1
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Default My downpipe (because no one looks at my other thread)

So as my first tig project for the car I decided to build my own downpipe. I had planned to use all stainless tubing but ran out. The two sections of tubing on the flex section are aluminized.

Don't mind the large haze sections on the stainless or the convexity of some welds. No I didn't backpurge and yes my fitment between tubes wasn't exactly perfect. Thus a couple places of burn through that had to be dealt with.

I have pretty much learned every lesson I can think of concerning this kind of tubing fabrication that comes to tig welding fitment, bolted down flanges, marking your **** correctly and w/e you can think of I did it or thought about doing it before catching myself. So it was a wild ride and i'm glad to be done with it.

The tubing is all from racing solutions columbia river mandrel bendings and so are the flanges. Flex, bungs, and 2-3" transition is from verocious.
I used 2.25" tubing off the flange and transitioned to 3" as you can see with the WG dumping back in after the transition.








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Old 05-12-2008, 01:32 AM   #2
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looks pretty damn good
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Old 05-12-2008, 02:05 AM   #3
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What's the use for the 3 npt ring? Wideband and?
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Old 05-12-2008, 02:07 AM   #4
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Stock narrowband to keep CEL's away.
Wideband at 12 o-clock because its runs through the shifter hole.
Dyno wideband just in case I want to thread one in precat instead of post cat in the tailpipe.
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Old 05-12-2008, 02:59 AM   #5
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Looks good for your first TIG job, only thing I can see being an issue is how the WG tube connects at a rather sharp angle and very close to the turbine exit. Might not be optimal for flow.
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Old 05-12-2008, 06:09 AM   #6
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so now the million dollar question..... does it fit?

begi
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Old 05-12-2008, 07:23 AM   #7
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I need to widen one of the holes in the turbo flange a little otherwise it fits fine. I'll post pictures of fitment when i get time to finish the install.
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Old 05-12-2008, 09:56 AM   #8
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very nice job.
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Old 05-12-2008, 09:57 AM   #9
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Looks good to me. WG reentry at the expansion seems logical. I went with 3 o2 bungs also - and just plugged the dyno port. Did you consider drill n tap for egt on the mani before install. You can always plug and use later.
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Old 05-12-2008, 10:05 AM   #10
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I'm glad you did the TIG work yourself. Keep practicing, it'll be worth it!
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Old 05-12-2008, 10:24 AM   #11
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Looks pretty good man. Good Job!!
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Old 05-12-2008, 10:27 AM   #12
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Default for discussion sake

Still thinking about the reentry of the wg tube and wondering what's ideal. It makes sense that reentry at the expansion would work since the main flow of exhaust is expanding at that point, but on the flip side is it creating more disturbance in the flow because it's entering during this expansion? What's ideal? Would a greater angle be more desirable? That would create a larger entry port - and in the image below would also enhance the reentry (at the price of a tighter exit from the wg) since the wg pipe is transitioning at the same angle as the dp. I realize that space plays a part- and a side mount will have less room. But I've got a top mount and plan to add an ewg port at some point. Comments from the experts?

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Old 05-12-2008, 10:33 AM   #13
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since he's doing it just out of the transition into 3" i think it's a good spot. I doubt you'd notice any difference between the two spots above. anything is better than my T3.
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Old 05-12-2008, 10:35 AM   #14
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Quote:
Originally Posted by m2cupcar View Post
Comments from the experts?
Quote:
Originally Posted by Braineack View Post
since he's doing it just out of the transition into 3" i think it's a good spot.
Brain, he said experts.
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Old 05-12-2008, 10:38 AM   #15
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oh yeah. duh
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Old 05-12-2008, 11:15 AM   #16
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the experts say it's 100x harder to make the wg line that long and still have it fit... at least when your WG is on top of the manifold. chad has no excuse.
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Old 05-12-2008, 11:36 AM   #17
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Quote:
Originally Posted by y8s View Post
...at least when your WG is on top of the manifold...
what about the number 4 runner? Chad's last wg pipe was about 10x longer, but that came from the rear of the turbine housing so it was easy.
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Old 05-12-2008, 11:41 AM   #18
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it's just too damn tight in there to snack two pipes. i'm a rookie here!
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Old 05-12-2008, 12:49 PM   #19
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I suppose the DPs that do have a merge that far down are utilizing the additional space created by the smaller 2.5" dp diameter
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Old 05-12-2008, 12:52 PM   #20
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How about sending the WG dump back into the intake for some DEI action?
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