AA EL Mid Pipe Rattle Thread

[onebadm3]

Mine has the cold start rattle from the rear which goes away after the car warms up. I assumed it was probably the flaps in the muffler. Other than that the car sounds great!

[mike@x-ph.com]

Originally Posted by onebadm3

Mine has the cold start rattle from the rear which goes away after the car warms up. I assumed it was probably the flaps in the muffler. Other than that the car sounds great!

my cold start rattle was fixed when i adjusted the midpipe

[shahano]

Originally Posted by biggripper

I think this may become helpful thread in the future with more users getting their AA EL Mid Pipes installed.

I still have some intermittent rattling even after identifying/eliminating two. Also before I continue let me state that I did install new gaskets at the down-pipe outlets. I don't know how anyone could get away with reusing the old ones. Mine were badly deformed and shredded. Do yourself a favor and just replace these. Consequently this is the only part of the system that doesn't leak any water.

Here's what I've found and fixed followed by what I haven't found.

What I Have Found/Fixed
1) heat shield contacting midpipe on passenger side more towards the front (between down pipes and cross brace). The degree of contact with the midpipe here was quite surprising but only required a long screw driver to bend the shielding back a bit in select spots.

2) Cross brace contact. Even with the Active Autowerke cross brace it's still possible to contact. To remedy this I simple loosened the ball clamps and inserted a temporary spacer between the cross brace and mode pipe, then re-tightened the ball clams prior to removing my spacer block. If the problem reoccurs I may use the "ol' washer method" to provide some extra spacing for the cross brace.

What I haven't Found:
1) Cold start rattle. This rattle only seems to occur in the morning after I start the car. It self-resolves after less than a minute of engine idling. It sounds like it's coming from the back muffler area. My suspicion Is that it may possible be contact at the cut point between the stock exhaust pipes and the mid pipes. Per the installation manual there is supposed to be a slight gap between the cut pipes and the mid pipes. Although I did measure 1.5" from the weld I feel like my gap didn't quite look like the gap in the install manual.

UPDATE—after speaking to someone at active this cold start rattle is likely my exhaust flaps. Which are known to rattle a bit when cold. It's probably more obvious in my case because I used my VSC-2 valve controller to close them prior to early morning cold starts in order to save my neighbors.

2) My last rattle seems to emanate from what seems to rift underneath the DCT shifter. It's a very low rattle that I might describe as a shudder rather than a rattle. It seems to occur only at very low speeds. I notice it most frequently when the car is on a slight angle driving out or backing into my driveway. My though is that something about the angle of the car is affecting the angle of the engine/exhaust components enough that the mid pipe is making contact somewhere—probably somewhere in the tighter portion of the tunnel.

UPDATE— after talking to Active, it sounds like this is most likely a symptom of how I tightened the connections with the down pipes. With the OE downpipes the right downpipe has a fixed flange where as the left has a floating flange. By tightening the fixed flange first the midpipe will naturally crowd the left side of the car. The tech I spoke to recommended securing the left (floating) side first and making sure the tunnel spacing left-to-right looks good prior to tightening the right side.


Anyway I suspect others will have some minor rattles with this product also, so I thought it would be helpful if people could share there findings and remedies.

Thanks for this, i have the rattle under the gearbox either at idle or when I am at 1200 rpm, I am going to try the left and right flange like you mentioned.

[Dino355]

Did you guys with the rattle under the gearbox resolve the issue?

I have the same problem on my M2C, taking a look again tomorrow.

[MineralWhiteF80]

i had the metallic rattle under the gearbox/passenger seat. It only happened when the car was either stopped with the engine running at a slight angle, or if i was slowly moving in or out of a parking space or my garage.

after looking multiple times and trying to bend heat shields and adjusting the new center brace Active supplied, i finally found the issue:

It was the small welded tab that holds the two exhaust pipes together between where the mid-pipe attaches to the downpipes and the first 90* bends that the midpipe makes toward the centerline of the car.

The weld point on one side of the tab broke causing the rattle. I pushed up on the broken side of the tab to create more clearance and the rattle was fixed

The broken weld caused the thin metal tab bracket and half the weld bead to just lightly rest on the other half of the weld bead/exhaust pipe and with the right amount of engine/exhaust pipe vibration, the tab bracket would make the metallic rattle.

the tab bracket broke because the AA EL midpipe hangs down a little low, my car is lowered a good bit, and the midpipe drags over speed bumps to the point it put enough pressure on the front of the midpipe to break that little tab off on one side

[mike@x-ph.com]

Originally Posted by MineralWhiteF80

i had the metallic rattle under the gearbox/passenger seat. It only happened when the car was either stopped with the engine running at a slight angle, or if i was slowly moving in or out of a parking space or my garage.

after looking multiple times and trying to bend heat shields and adjusting the new center brace Active supplied, i finally found the issue:

It was the small welded tab that holds the two exhaust pipes together between where the mid-pipe attaches to the downpipes and the first 90* bends that the midpipe makes toward the centerline of the car.

The weld point on one side of the tab broke causing the rattle. I pushed up on the broken side of the tab to create more clearance and the rattle was fixed

The broken weld caused the thin metal tab bracket and half the weld bead to just lightly rest on the other half of the weld bead/exhaust pipe and with the right amount of engine/exhaust pipe vibration, the tab bracket would make the metallic rattle.

the tab bracket broke because the AA EL midpipe hangs down a little low, my car is lowered a good bit, and the midpipe drags over speed bumps to the point it put enough pressure on the front of the midpipe to break that little tab off on one side

Glad to hear you figured it out