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  1. #1
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    3 out of 3 members liked this post. Yes Reputation No

    Downpipe Positioning Causing Vibration

    Hey guys,

    I am hoping that someone with experience with my issue can chime in. Kind of frustrated at this point as I have been trouble shooting for a few days after work. Story time...

    I installed new turbos 2 weeks ago. I also upgraded my clutch to the 335is clutch, did the delay valve delete, and installed a new stock dual mass flywheel while I was under there.

    Install went well, engine started up fine and everything.

    Under load/boost and when coasting, I had a very strong vibration in 2nd gear and 3rd gear from ~2500-3200rpm. Past that the vibration can't be felt, and at higher speeds 4th gear+ I can't feel anything either.Also, if I keep the engine out of boost, there is zero vibration going through those RPMs.

    I initially thought that the issue was my driveshaft and heat shielding hitting the exhaust, but I looked and didn't see any scratches on the driveshaft.

    I then saw the downpipes were close to the engine as I show below. I saw some light scratch marks on the downpipe near this part of the block and also noticed some oil on the turbo.

    Click here to enlargeClick here to enlargeClick here to enlarge

    I adjusted the downpipe to be further from the engine, but my exhaust puts a lot of stress on the downpipe pulling them down and I can't make too much clearance without removing clearance from the engine mount bolt.

    I tried adjusting the hangers to allow the exhaust to sit higher to remove the stress it puts on the downpipe, but I think I may have warped the exhaust when I did the performance mod and was grinding and welding on the driver side (driver side exhaust tip isn't concentric with the diffuser anymore like the passenger side). So anyway it is very difficult to have the exhaust lined up perfectly with the downpipes.

    I ran the car and the vibration seemed to be less but it is still faintly there.

    So anyway, can someone help me out with this issue?

    Which gaps are critical between the downpipe and engine/mount bolt/subframe?
    Do you think the oil is coming from the stress and then vibration on the turbo, or just my install of the gasket on that oil line?
    Is there another way I can adjust the exhaust more?

    Any other possible problems this could be?

    Thank you all,
    Click here to enlarge
    Click here to enlargeClick here to enlargeClick here to enlargeClick here to enlargeClick here to enlargeClick here to enlargeClick here to enlargeClick here to enlargeClick here to enlarge

  2. #2
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    2 out of 2 members liked this post. Yes Reputation No
    are you sure your carrier bearing isnt upside down?

  3. #3
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  4. #4
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    1 out of 1 members liked this post. Yes Reputation No
    Click here to enlarge Originally Posted by boosted_k20 Click here to enlarge
    are you sure your carrier bearing isnt upside down?
    Worth checking. I accidentally did this when going single turbo and it caused me headaches for weeks.
    ACF PTE 6062 BB Top Mount ST Kit, Fuel-It! Stage 3 LPFP, Phoenix Racing Port Injection Manifold + RACE FMIC, JB4 + BMS ST E85 PI BEF

  5. #5
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    @E92335 you figure it out?

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