[k3vin0615]

there is not need to get an alignment if you are just lowering the frame without removing all the bolts.

ive done this in many cars for other different repairs and there is no alignment needed

[TheGoodTheBadTheUgly]

Originally Posted by k3vin0615

there is not need to get an alignment if you are just lowering the frame without removing all the bolts.

ive done this in many cars for other different repairs and there is no alignment needed

When you are saying without removing all the bolts, I guess you are referring to the steering components bolts?

[k3vin0615]

Originally Posted by TheGoodTheBadTheUgly

When you are saying without removing all the bolts, I guess you are referring to the steering components bolts?

are you aware that the rack mounting points themselves do not have any adjustment. is like you asking if the car needs an alignment after taking off the rotors.
unless you are messing around with the inner or outer tied rods you wound be changing anything.

[Pladi]

Originally Posted by k3vin0615

are you aware that the rack mounting points themselves do not have any adjustment. is like you asking if the car needs an alignment after taking off the rotors.
unless you are messing around with the inner or outer tied rods you wound be changing anything.

he is asking if u have to remove the steering rack or unbolt for this job and not about alignment.

[CurtisP87]

Originally Posted by TheMidnightNarwhal

I asked about that and everyone told me to not remove cold starts as it's not wise even if your catless.

The whole point of a cold start is to warm up the cat converter so it gets to its most efficient temps more quickly....no cats means no need for cold start. Not sure who told you that.

[carguy138]

Originally Posted by CurtisP87

The whole point of a cold start is to warm up the cat converter so it gets to its most efficient temps more quickly....no cats means no need for cold start. Not sure who told you that.

I used to think that too but it seems like there is much more to cold start than just warming up the catalytic converter for tail pipe efficiency. I remember reading an article by an auto engineer that worked exclusively on cold starts and there was way more to it. Had to do with thermal expansion of critical engine components and the importance of an initial rich fuel mixture for non-obvious reasons. If I can find it, I'll post it.

The tolerances on a cold engine are much tighter and higher RPMs gently speed up the thermal expansion process. The faster an engine can get to operating temperature, the less blow by occurs which reduces oil dilution by fuel. Also reduces ring and cylinder wear.

The problem when you try to warm up an engine too quickly, such as beating on a cold engine, you have dissimilar metals expanding at different rates. This is notorious in the two stroke dirt bike world when running forged pistons. The forged pistons expand at a faster rate than the cylinder which can cold seize the motor. On the opposite side of the spectrum, just like having too tight of a ring gap. As the ring heats up and expands, if the gap is too tight, the two opposing portions of the ring will touch and can fold over causing it to seize. When this happens usually piston cracks, pieces of the ring explode and gouge up the cylinder head and score the cylinder.

Need to let the engines warm up gradually before giving it the beans.

Smaller scale but similar principles. Two stroke nitro motors found in 1/8 and 1/10 RC cars are extremely sensitive to this. Those engines don't have piston rings and rely on the "pinch" between the cylinder and piston for compression. I found that engines broken in during the winter or used extensively in the winter (where they rarely get close to operating temperature) had much lower compression and wouldn't idle when it warmed up. We found out pretty quickly to use an old beater engine for colder months and save the high dollar motors for the summer.

Long story short, there is much more to the subject than what meets the surface. It might not be as critical in hot climates like TX or FL and much more applicable to areas with brutal winters. YMMV.

[StephenB.n55]

Originally Posted by JoshC222

I have a 2011 e90 335ix 6MT, and I installed my downpipe on jack stands without dropping the subframe. You 100% do not need to. Maybe it's different for auto trans? I'm not sure.

Take off the pass wheel and fender liner. You work half thru there, half from underneath.

Same about the subframe. I have an e92 xdrive auto (I don't know what the subframe clearance situation is between e90 vs e92). Anyways, I removed the heat shielding in between the downpipe and the subframe. I also had to leave the front 02 sensor on the stock downpipe during removal because it was rusted on. I wanted to die during the whole thing but it was accomplished with needed access via the wheel well (with the passenger wheel off but the fender liner still on). Also a headlight is a musttttt. At the time I had lost mine and was holding a flashlight in my mouth as I tried to wiggle on a million different extension/wrench combos for several bolts.

[TheGoodTheBadTheUgly]

Originally Posted by StephenB.n55

Same about the subframe. I have an e92 xdrive auto (I don't know what the subframe clearance situation is between e90 vs e92). Anyways, I removed the heat shielding in between the downpipe and the subframe. I also had to leave the front 02 sensor on the stock downpipe during removal because it was rusted on. I wanted to die during the whole thing but it was accomplished with needed access via the wheel well (with the passenger wheel off but the fender liner still on). Also a headlight is a musttttt. At the time I had lost mine and was holding a flashlight in my mouth as I tried to wiggle on a million different extension/wrench combos for several bolts.

Wow ok this is really starting to sound like a pain haha. Thanks!

[carguy138]

Originally Posted by StephenB.n55

Same about the subframe. I have an e92 xdrive auto (I don't know what the subframe clearance situation is between e90 vs e92). Anyways, I removed the heat shielding in between the downpipe and the subframe. I also had to leave the front 02 sensor on the stock downpipe during removal because it was rusted on. I wanted to die during the whole thing but it was accomplished with needed access via the wheel well (with the passenger wheel off but the fender liner still on). Also a headlight is a musttttt. At the time I had lost mine and was holding a flashlight in my mouth as I tried to wiggle on a million different extension/wrench combos for several bolts.

Great advice. I just took a look underneath and you can easily get to the vband clamp from the front portion of the wheel well. Looks like a couple 12" 3/8" extensions and a wobble bit would get to it. From this angle it looks much easier than I thought.

Did you have an problems pulling the downpipe out once the bracket, O2 sensors and vband clamp were off?

[tman68]

Don't mean to revive an old thread but I just want to make it clear that on an E90 n55 xdrive there is absolutely no need to lower the subframe or remove any kind of suspension on the passenger side. Just remove the wheel to access the bolt to v band clamp. Unplug the o2's topside and remove the wires from the brackets (no need to remove the front o2 from the cat yet). Remove the bracket that holds the cat to the trans. Drop the whole exhaust so you can pull the cat straight back and out. I have to say it sounds easy but it's kind of a bitch to do. Definitely doable though

[iwantaw335]

E92 xdrive absolutely need to drop subframes. You will need like 5-6” drop, may need to tilt front up and back side down

[Pladi]

Originally Posted by tman68

Don't mean to revive an old thread but I just want to make it clear that on an E90 n55 xdrive there is absolutely no need to lower the subframe or remove any kind of suspension on the passenger side. Just remove the wheel to access the bolt to v band clamp. Unplug the o2's topside and remove the wires from the brackets (no need to remove the front o2 from the cat yet). Remove the bracket that holds the cat to the trans. Drop the whole exhaust so you can pull the cat straight back and out. I have to say it sounds easy but it's kind of a bitch to do. Definitely doable though

TheGoodTheBadTheUgly Have you been lying to me this whole time ?????

[carguy138]

Originally Posted by tman68

Don't mean to revive an old thread but I just want to make it clear that on an E90 n55 xdrive there is absolutely no need to lower the subframe or remove any kind of suspension on the passenger side. Just remove the wheel to access the bolt to v band clamp. Unplug the o2's topside and remove the wires from the brackets (no need to remove the front o2 from the cat yet). Remove the bracket that holds the cat to the trans. Drop the whole exhaust so you can pull the cat straight back and out. I have to say it sounds easy but it's kind of a bitch to do. Definitely doable though

+1. I did this several months ago and that's spot on. Never touched the subframe.

edit: 2011 E90 N55 xdrive 6MT

[Pladi]

Originally Posted by tman68

Don't mean to revive an old thread but I just want to make it clear that on an E90 n55 xdrive there is absolutely no need to lower the subframe or remove any kind of suspension on the passenger side. Just remove the wheel to access the bolt to v band clamp. Unplug the o2's topside and remove the wires from the brackets (no need to remove the front o2 from the cat yet). Remove the bracket that holds the cat to the trans. Drop the whole exhaust so you can pull the cat straight back and out. I have to say it sounds easy but it's kind of a bitch to do. Definitely doable though

AT or MT ?

[TheGoodTheBadTheUgly]

Originally Posted by tman68

Don't mean to revive an old thread but I just want to make it clear that on an E90 n55 xdrive there is absolutely no need to lower the subframe or remove any kind of suspension on the passenger side. Just remove the wheel to access the bolt to v band clamp. Unplug the o2's topside and remove the wires from the brackets (no need to remove the front o2 from the cat yet). Remove the bracket that holds the cat to the trans. Drop the whole exhaust so you can pull the cat straight back and out. I have to say it sounds easy but it's kind of a bitch to do. Definitely doable though

I don't know if there is a difference between the MT and AT under that car in the area near the Downpipe, apart from the transfer case, but let me tell you, getting the V-Band clamp off without removing some stuff out of your way is barely doable.

The first thing to do would be to work on the exhaust side which is pretty easy. You can get that bracket of no worries and even start working on the connection between the exhaust and the downpipe. It is also much easier, like you mentioned, to drop the whole catback in order to pull it away and give you space to remove the downpipe later.

What is really tricky is that V-band clamp. It is so cramped up in there that it's frustrating to work with it. I managed to unscrew it without touching any of the suspension components, but then I wondered how I was going to spread it open manually with my hands and even more how I was going to position the new downpipe inside of it and tighten it back. Honestly, in sight of the horror that would be generated by trying to fiddle with that, I just pulled the passenger side axle. Took 5 more minutes and give you all the space you need to wiggle yourself in an amazing position where everything is much easier!

Subframe wise it might be possible to not even touch it, but I didn't want to waste time. You don't have to worry to much about it, just unscrew (a bit) 2 of the subframe bolts near the downpipe to allow it to lower about 2 inches. It takes 10 seconds. This will give you enough clearance to twist the downpipe and remove it out of where it is sitting!

You are absolutely right about the O2 Sensor part. Just unplug them from the top and let them dangle down. Down need to touch them until you have the downpipe off. Be careful with these, my downstream O2 got cross threaded when removing so I had to get that Bosch universal Wideband O2 sensor for our model which works great.

[tman68]

Not sure about the e92's but on the 2011 e90 n55 xdrive mt there was no need to touch the subframe or suspension components. Just drop the exhaust and snake the cat back

[tman68]

I was able to get to the v band with an extension and 13mm swivel socket through the passenger side wheel well

[iwantaw335]

2011 e92 coupe auto. White arrow points to part of the subframe that’s in the way.

[tman68]

Can't fully tell from the pics but from what I see it doesn't look much different than the e90. Looks to me if you dropped the exhaust like I did you probably would've been able to snake it straight back. But like I said I can't really tell from the pics and I can only comment on my experience on my car. I just wanted to clear things up for people who are looking to do a downpipe on an 2011 E90 n55 MT that there is no reason to touch any subframe bolts. If you rather do that than drop the exhaust then by all means do what is easiest for you. If anyone has any questions about the job feel free to message me. I'll try and help any way I can.

[cranelec]

Originally Posted by TheGoodTheBadTheUgly

As the title says, I am going to install downpipes for my car soon. The only problem is that's it seems to be a process that is way more hectic than on a RWD 335.

So I would like to know, preferably from people who did it on their xDrive 335 or from people who knows about the process, how to install the downpipes.

I have heard that you need to drop the subframe in order to access the downpipes mounting point. Does the whole subframe have to come off or you can just lower it a bit? Do you have to remove the steering rack?

Any details or insight is appreciated!

Let me make this very simple:..& easy for any shade tree mechanic:
CAR HAS ENDURED FIVE WINTERS OF ROAD SALT! (Note: I did the PS2 & down pipe at the same time).
1. I lowered my X drive sub-frame
(4 bolts loosened 3/4")
2. I removed the passenger side motor mount.
(2 bolts + 1 nut)
3. Next, I raised my engine slightly with a floor
jack.
4. With passenger tire off, I easily removed the
the v-band.
5. Due to steps 1, 2, & 3, removing, I had more
enough room to remove the cat with ease.
6. I removed the entire fender liner which
allowed me a clear shot at the severely
corroded turbofold fasteners.

Obviously, the extra bolts, etc. added approximately 90 minutes to the job. I believe that the approach as described above not only saves time, it also makes the entire process less frustrating.

[drummr8]

Some additional tips here:
https://www.e90post.com/forums/showthread.php?t=1669354

Good luck!