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Old 03-03-2008, 01:25 AM   #1
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Default Think I found my exhaust leak...

I noticed a gentle overtone of fuel when driving the other day, and after staggering out of my car desperate for fresh air (even funnier in a convertable) I noticed this small gap where apparently some fumes managed to escape:



So, your hero pack the "trunk" of his other car and headed to NSFab for a bit of fix-er-up'ing.



Needless to say, it's all better now, and the top several inches of my downpipe are now stainless steel.

Also, I got rid if the ridiculous, 1 hour to remove FM downpipe studs thing, and now have nuts on the DP itself, and I drop bolts in from above the elbow. It goes together with a socket and an extention and takes like 5 minutes.
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Old 03-03-2008, 01:41 AM   #2
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That's pretty ridiculous. Did the weld crack all the way around or was it the heat affected tubing cracking? Do you know if they only weld the outside instead of the inside?
But where are the pics of the new modification, i know you took some.
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Old 03-03-2008, 01:41 AM   #3
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Looks like ya might have had a little leakage going on there...
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Old 03-03-2008, 02:04 AM   #4
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how did u get ur camera in there?
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Old 03-03-2008, 02:53 AM   #5
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Looks like they just laid a surface bead. There isn't even any evidence of a pipe ever being welded to half of that flange.
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Old 03-03-2008, 03:00 AM   #6
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I talked to Corky about why they weld the inside and not the outside. They experienced all kinds of failures like this one when welding the outside. The weld would break right at the meniscus just like this photo shows. So they now weld the inside and stitch the outside to allow for heat cycling and other fatigue apparently.
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Old 03-03-2008, 09:45 AM   #7
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is there a flex pipe in that setup?
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Old 03-03-2008, 09:53 AM   #8
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I belive so

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Old 03-03-2008, 11:02 AM   #9
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flex pipes....

hey abe, did you get massive backfires on that thing?

oh and if they were doing their welds correctly, wouldn't the weld fully penetrate the pipe AND flange at the joint and fuse the material at the root of the weld? If they're just doing a fillet on the outside, it's done wrong.

Like when I weld mine up, I verify there's penetration on the inside... who knows.
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Old 03-03-2008, 11:57 AM   #10
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Quote:
Originally Posted by y8s View Post
flex pipes....

hey abe, did you get massive backfires on that thing?

oh and if they were doing their welds correctly, wouldn't the weld fully penetrate the pipe AND flange at the joint and fuse the material at the root of the weld? If they're just doing a fillet on the outside, it's done wrong.

Like when I weld mine up, I verify there's penetration on the inside... who knows.
If my new BEGI downpipe didn't have the flex section it wouldn't have fit.
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Old 03-03-2008, 09:20 PM   #11
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Quote:
Originally Posted by y8s View Post
flex pipes....

hey abe, did you get massive backfires on that thing?
Yep, how did you know? I was sure the turbo would be dead from the backfires, but it's completely perfect in every way. But the pipe had a good sized hole in it, which got bigger of the week or two I let it go.

Quote:
Originally Posted by cjernigan View Post
I talked to Corky about why they weld the inside and not the outside. They experienced all kinds of failures like this one when welding the outside. The weld would break right at the meniscus just like this photo shows. So they now weld the inside and stitch the outside to allow for heat cycling and other fatigue apparently.

Interesting. If you look close, you'll see this was only stiched on the outside, and there was some weld on the inside as well. Yes, it has a flex pipe.

I'm going to try to get some pics later today of the final install.
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Old 03-03-2008, 09:21 PM   #12
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this is the pipe FM builds, not ones Corky used to, correct?
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Old 03-03-2008, 09:34 PM   #13
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Don't acutally know. It's old-but-not-that-old. On the kits with the old style intercooler.
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Old 03-03-2008, 10:57 PM   #14
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Quote:
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Yep, how did you know? I was sure the turbo would be dead from the backfires, but it's completely perfect in every way. But the pipe had a good sized hole in it, which got bigger of the week or two I let it go.

I know because mine had a 3-bolt flange at the same point that came loose on the track. sounded ******* badass. zooom BANG BANG POP BANG zooom!

the backfires are goin out followed by hot exhaust gas. that's why they didnt hurt the turbo. any plastic near there though... eep.

I also know because I just told faeflora I think that his exh leak was causing his backfires.

basically unburnt fuel during shifts plus hot exhaust plus fresh air = exploding.
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Old 03-03-2008, 11:02 PM   #15
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Oh, ah, well my backfires were all MS-related. At least, some of them were, the ones that broke the pipe open.

On the other hand, no downpipe makes it really easy to tune, you can hear every little burble of the motor.



And


Really easy to get on and off. Color me happy. the only issue now is it likes a slight twist when you put it on to best clear the tranny. I did this with two people, and while I know I could do it with one, it would be nice if it were less adjustable. :-)
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