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BMW 3-Series and 4-Series Forum (F30 / F32) | F30POST > Technical Forums > N55 Turbo Engine / Drivetrain / Exhaust Modifications > N55 downpipe install leak?
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      01-25-2018, 01:06 PM   #1
izaazk
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N55 downpipe install leak?

my buddy and i installed a catless downpipe into my f30 n55 over the weekend...

i feel like its leaking somewhere because there is some drone and sounds "boomy" in the cabin...

also can not hear the turbo spool at all

We double checked the vbands before we put it back together..

Stock exhaust with catless...

sounds extremely deep and cracks and pops but no turbo spool sound....

You guys think it could be a leak?
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      01-25-2018, 01:23 PM   #2
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Curious which downpipe you went with?
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      01-25-2018, 01:24 PM   #3
izaazk
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VRSF

It's coated silver with a flex section
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      01-25-2018, 01:31 PM   #4
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Thats odd

I was under the impression that the N55 does not have a flex joint in the down pipe! Have you contacted the seller to confirm you ordered the correct part for your vehicle?
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      01-25-2018, 01:34 PM   #5
izaazk
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I bought it from a private seller on here....

I googled around and this is what it pops up for f30 n55 2012 3.5" downpipe...

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      01-25-2018, 01:36 PM   #6
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Quote:
Originally Posted by Munchi435i View Post
Thats odd

I was under the impression that the N55 does not have a flex joint in the down pipe! Have you contacted the seller to confirm you ordered the correct part for your vehicle?
Yes, the 3.5" for PWG has the flex joint. I have one.
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      01-25-2018, 01:42 PM   #7
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ohhhhhhh ok, i was about to email the company about the flex joint but im guessing they removed the flex joint for the 4in dp
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      01-25-2018, 02:36 PM   #8
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With a cold car, start the car then run over and stick your head under near the DP. If you have an exhaust leak you will hear it.


Quote:
Originally Posted by izaazk View Post
my buddy and i installed a catless downpipe into my f30 n55 over the weekend...

i feel like its leaking somewhere because there is some drone and sounds "boomy" in the cabin...

also can not hear the turbo spool at all

We double checked the vbands before we put it back together..

Stock exhaust with catless...

sounds extremely deep and cracks and pops but no turbo spool sound....

You guys think it could be a leak?
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      01-25-2018, 09:57 PM   #9
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      01-25-2018, 10:06 PM   #10
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With a downpipe you usually can hear the leak or even see soot around the flanges
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      01-25-2018, 10:39 PM   #11
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Quote:
Originally Posted by JaredG_F30 View Post
With a cold car, start the car then run over and stick your head under near the DP. If you have an exhaust leak you will hear it.
This.

No other sure fire way to detect it. You should fee a nice stream of cold air around the flanges if there is a leak.
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      01-26-2018, 03:47 PM   #12
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Quote:
Originally Posted by paimon.soror View Post
This.

No other sure fire way to detect it. You should fee a nice stream of cold air around the flanges if there is a leak.
I had a leak as well. Spray some soapy water on the joints. Take a video of the dp to see any bubbles upon start and revs.
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      01-26-2018, 04:10 PM   #13
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Derp, yep that works too Might get a nice soapy stink when it heats up, but good call
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