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      11-14-2019, 01:28 PM   #1

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N55 Xdrive Downpipe Install - no subframe removal

I know this has been mentioned in quite a few threads, but I just wanted to try and help out someone who may be planning to tackle this job on their xDrive. It is 100% possible and not that difficult to do the downpipe without lowering the subframe. The most difficult part for me was getting the stupid V-band clamp back on. Patience is key there... it's tight, and it will definitely make your hands hurt.

Pictures for reference when reading through tips:

Dropping the exhaust gives you much more room to do things, and makes it easier to slide the downpipe out. Actually, I'm not sure it's possible without dropping the exhaust. Nevertheless, it's like 8 bolts I think, none of which are difficult to remove or put back in.

The downpipe to exhaust nuts will likely be severely corroded, especially if you are from a northern state. For me, I used lots of PB blaster (let it soak a few times before even attempting). Two other tricks for rusty old bolts or nuts - buy a set of "damaged bolt and nut remover sockets" (see my pictures) and also try fitting an American standard socket over a rusted nut (7/16" in this case for me). Sometimes the rust eats through the nut evenly, and causes it to size down by half a mil. A lot of times you can get a perfect fit with an American standard socket.

For loosening the V-band clamp bolt, it's a 13mm. There's a picture of the setup I used to remove it, also shows where exactly I fed this through to reach the bolt. I removed the passenger wheel and wheelhouse liner. Not sure if removing the wheelhouse liner really did much for me, but others recommended it.

Definitely remove the small heatshield under the downpipe as well as the transmission bracket that bolts to the downpipe. Get these totally out of there as soon as you're able. If I recall correctly, I couldn't get the heatshield out totally until I had the downpipe loose. This heatshield needs to be completely out in order to fit the downpipe through the opening and remove it. The downpipe comes straight back toward the exhaust.

For the O2 sensors, leave both on the downpipe when pulling the downpipe out. You just need to rotate the downpipe to accommodate the sensors as you pull it out. Disconnect the sensors up top under the engine cover and feed them down. When you go to reinstall, it's kind of a pain to get the sensor connectors back up. I dropped a string down the backside of the engine and tied it to the connectors to pull them up. Requires some wiggling.

Hopefully this longwinded post can help someone with the job. Again it's not super difficult, you can totally DIY. Just have some patience, and try not to hurt your hands too much (hopefully you have tiny hands :P). If you've done the water pump on an xDrive car, then you can definitely handle this. The water pump is far more cramped, and much much more of a gigantic pain in the ass
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      11-14-2019, 03:17 PM   #2
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Ah the beauty of a non-rusted southern car....

Thanks for posting all the tips! We'll see if I build up the courage to do this myself at some point.
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      11-25-2019, 10:34 AM   #3
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Nice, honestly I think lowering the subframe ain't bad at all, this looks more tedious/frustrating.

2008 335xi 6MT | VRSF Catless DP | VRSF 7" FMIC | VRSF CP | TIAL BOV | DCI | MHD 2+
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