[BabyX6]

Hey guys.

BMW leaser for the past 4 years, X3 m40i and now an X4 m40i. And now my X2 m35i is about to port in LA. I'm going to finance it, and for the first time do some typical vanilla flavored mods.

I've attached a screenshot of an email I got from the guys at German Car Accessories, who just today suggested that the downpipe for the F39 is compatible with the U10. They used my VIN# to check. Their aftermarket catted unit happens to be $1000, meanwhile there's one for $380 on Alibaba.

Anyway, does anyone have anything to comment about this? Does it check out? I hate to spend the $400+ only to have it not be compatible. And be stuck with it.

And yes I'm giving up the b58 x4 intentionally. I like the size and the appearance of the X2 better. I also test drove one and felt that after it gets moving, it wasn't significantly slower than my x4. That being said... off the line is a different story! I will miss having my neck broken when launching.

Anyway, thanks for any input!

[portimaobluex1]

I just purchased my x1 m35 and I was wondering the same thing about a downpipe. Could you please send me the alibaba link where you found the downpipe? Thank you.

[FlashMonkey929]

I'm a bit skeptical about them being the same, though it *may* fit. Thing is, is that the X4 is a longitudinal oriented engine and RWD, and the X2 is a transverse mounted engine and FWD based. It might fit, or it might be off just slightly enough to cause problems installing it. If you want it that badly, you could take the chance and be the guinea pig for everyone else. $380 for a decent downpipe is cheap!

[Readimag]

Originally Posted by FlashMonkey929

I'm a bit skeptical about them being the same, though it *may* fit. Thing is, is that the X4 is a longitudinal oriented engine and RWD, and the X2 is a transverse mounted engine and FWD based. It might fit, or it might be off just slightly enough to cause problems installing it. If you want it that badly, you could take the chance and be the guinea pig for everyone else. $380 for a decent downpipe is cheap!

I was also confused at first but what the OP is saying is last model years x1/x2 downpipe should fit. Unless I’m totally wrong also haha. If true that would be sweet, I wonder if the charge pipes could also fit.

[FlashMonkey929]

Originally Posted by Readimag

I was also confused at first but what the OP is saying is last model years x1/x2 downpipe should fit. Unless I’m totally wrong also haha. If true that would be sweet, I wonder if the charge pipes could also fit.

Ahhh, gotcha. I guess I didn’t properly read that all the way through. It has a better chance of fitting, but still taking a chance.

[BabyX6]

Hey all!

First - the downpipe I bought is for an F39 X2, the previous generation. The OEM parts drawings of the F39 and the U10 stock downpipe are identical despite being different part numbers. So if there's a physical difference between them, it'll be minute. Which will make this that much more devastating.

My car is scheduled for Monday Dec 2nd at 8am for lowering springs AND the downpipe. I may only leave with lowering springs. I may leave with the those and a downpipe. Stay tuned. If the downpipe fits, I'll broadcast the Alibaba link to the world!!!! Again $400 instead of $1000!! And the pipe is clean as hell. It's so pretty. I'll hang it on my wall if it don't fit.

Check back in 10 days

[abrandonment]

What gains/audible changes are expected?

[BabyX6]

Originally Posted by abrandonment

What gains/audible changes are expected?

It's all speculation! I haven't done a deep dive to try and uncover a documented before/after Dyno on a b48 with downpipe, but I'm of the belief that 10-20hp is a reasonable expectation. And I reasonably expect a significant improvement to the exhaust note. You won't catch me modifying any other part of our stock exhaust system, so I'm banking on this baby to make our bark a little louder. Well OK I might remove a resonator from the mid pipe if I got desperate.

What will hold this mod back a little for me is that I'm not deleting the cat. I'm just too old to deal with the problems that come with deleting it. I care more about convenience and legality than a couple hp or a couple decibels.

Anyway, we'll know in 8 days if this previous-gen downpipe works. Fingers crossed to the bone. I'm just worried sick that some angle or flange will be just barely different enough that it won't work.

[richiro]

Originally Posted by BabyX6

It's all speculation! I haven't done a deep dive to try and uncover a documented before/after Dyno on a b48 with downpipe, but I'm of the belief that 10-20hp is a reasonable expectation. And I reasonably expect a significant improvement to the exhaust note. You won't catch me modifying any other part of our stock exhaust system, so I'm banking on this baby to make our bark a little louder. Well OK I might remove a resonator from the mid pipe if I got desperate.

What will hold this mod back a little for me is that I'm not deleting the cat. I'm just too old to deal with the problems that come with deleting it. I care more about convenience and legality than a couple hp or a couple decibels.

Anyway, we'll know in 8 days if this previous-gen downpipe works. Fingers crossed to the bone. I'm just worried sick that some angle or flange will be just barely different enough that it won't work.

I appreciate you being the first to take the plunge on an experimental mod.

I too wondered whether or not a retrofit would work. Eager to hear back on the results.

[BabyX6]

Originally Posted by richiro

I appreciate you being the first to take the plunge on an experimental mod.

I too wondered whether or not a retrofit would work. Eager to hear back on the results.

I appreciate the appreciation! I've definitely had to adopt some reckless abandon with this. But the more affordable cost of the downpipe certainly helps. It looks like I could have even gotten it cheaper on AliExpress. But at some point, the lower cost could reflect in the product.

I've looked at countless diagrams and photos. While materials and trim of the stock downpipe have changed from old to new gen, the shape size and angulations all appear to be the same. Gaskets involved are the same, so that's promising. Anyway, the countdown is on. I'm being cautiously optimistic.

[richiro]

are you doing the install yourself?

[BabyX6]

Originally Posted by richiro

are you doing the install yourself?

No sir, but I'm still dropping her off tomorrow morning at the shop.

I just don't have an adequate enough shop for me to try to take it on personally.

[BabyX6]

My shop evaluated the downpipe with the car up in the air, and they didn't feel confident about it working. They didn't want to rack up a bunch of charges tearing it apart when they had no confidence. Additionally, they said the cat was poor quality (damn you, China) and felt it was risky that it could throw a CEL.

So! We still don't know for certain if the F39 downpipe actually works. It still might. But I'm happy to not throw more money at it just in case with my shop not feeling good about it.

Hell!!!!

[abrandonment]

Hate to hear that but thanks for the try!

[BabyX6]

Originally Posted by abrandonment

Hate to hear that but thanks for the try!

I picked the car up today after dropping it off yesterday, they finished putting my H&R lowering springs in. I had a chance to talk to him a little more about the downpipe. He said he had two main issues:

1) The exhaust flange on the end/exit of the downpipe is different. The F39 (and thus the downpipe I bought) terminates in a "v band" connection. Ours terminates (and meets the midpipe) with a tapered connection secured by like a band clamp. The flange could have been hacked up and modified but not ideal.

2) The cat itself. The new one from China that was built into the downpipe was homemade. Likely to throw a CEL, negating the point of having a catted downpipe. And so interestingly, I looked into this further... and it seems that the majority of aftermarket catted downpipes still throw a CEL because of the cat! I never knew this! It apparently takes a VERY high quality and/or 400+ cell catalytic converter for those O2 sensors to give the appropriate readings.

So his reluctance probably saved me a world of heartache. And I am putting a downpipe on a low priority list that now requires a reputable company to market it specifically for the U10 and to guarantee it won't throw a CEL!

Anyway, it was dark by the time I got the car so I couldn't take photos - but the springs dropped it by 1" and it looks slick as hell. So not all is lost!

[abirmaher]

Originally Posted by BabyX6

I picked the car up today after dropping it off yesterday, they finished putting my H&R lowering springs in. I had a chance to talk to him a little more about the downpipe. He said he had two main issues:

1) The exhaust flange on the end/exit of the downpipe is different. The F39 (and thus the downpipe I bought) terminates in a "v band" connection. Ours terminates (and meets the midpipe) with a tapered connection secured by like a band clamp. The flange could have been hacked up and modified but not ideal.

2) The cat itself. The new one from China that was built into the downpipe was homemade. Likely to throw a CEL, negating the point of having a catted downpipe. And so interestingly, I looked into this further... and it seems that the majority of aftermarket catted downpipes still throw a CEL because of the cat! I never knew this! It apparently takes a VERY high quality and/or 400+ cell catalytic converter for those O2 sensors to give the appropriate readings.

So his reluctance probably saved me a world of heartache. And I am putting a downpipe on a low priority list that now requires a reputable company to market it specifically for the U10 and to guarantee it won't throw a CEL!

Anyway, it was dark by the time I got the car so I couldn't take photos - but the springs dropped it by 1" and it looks slick as hell. So not all is lost!

Love to see some pics when you have light to take some. Considering these for my x1 m35.

My thought on downpipe was to look at something for the Mini platform as these engines/ drivetrains should be the same. When I installed my JB4 the mini guides were more helpful than the ones for the BMWs since the engines on these are transverse mounted likecthey have been in minis for years. Have not dedicated the time yet though to doing the research.

[abirmaher]

This was the best looking option I’d seen. One thing I noticed on this that I didn’t see on others was the option for AWD drivetrain which accounts for a front drive shaft, something I have not seen other downpipe options mention. See attached photo.

I’ve been running ER down pipes for over 10 years now on my m235 and then m2 without issue.

Catless: https://www.evolutionracewerks.com/node/330

Catted: https://www.evolutionracewerks.com/node/400

[BabyX6]

Originally Posted by abirmaher

This was the best looking option I’d seen. One thing I noticed on this that I didn’t see on others was the option for AWD drivetrain which accounts for a front drive shaft, something I have not seen other downpipe options mention. See attached photo.

I’ve been running ER down pipes for over 10 years now on my m235 and then m2 without issue.

Catless: https://www.evolutionracewerks.com/node/330

Catted: https://www.evolutionracewerks.com/node/400

Hello!!!

While the overall design of this model is accurate (as is any downpipe designed for a f39 m35i), the problem with it is that the exit flange is meant for a v-band clamp to secure it to the mid-pipe. The stock connection here is a slip-in, so a traditional band clamp would be appropriate.
That said, the design feature you pointed out that accommodates xdrive is also appropriate.

For me, living in Colorado, the catalytic converter is a sticking point. I'll eventually have to pass a strict emissions test. As a new car I do have a waiver for a number of years, but I'm a one-and-done kind of guy. So... I didn't learn until I already had the downpipe from China that there are also very few aftermarket cats that don't throw a CEL, even if they do pass emissions (not likely). If you live somewhere that you have no emissions testing, then by all means get the catless pipe with your dummy 02 sensor and life your life! Or if you do have emissions but you're willing to put the cat back after your grace period.

I was so bummed to not put it on - it's still sitting in the box in my garage. But since installing my custom axle-back, I'm in love with the way it sounds.


Good luck!

[abirmaher]

Originally Posted by BabyX6

Hello!!!

While the overall design of this model is accurate (as is any downpipe designed for a f39 m35i), the problem with it is that the exit flange is meant for a v-band clamp to secure it to the mid-pipe. The stock connection here is a slip-in, so a traditional band clamp would be appropriate.
That said, the design feature you pointed out that accommodates xdrive is also appropriate.

For me, living in Colorado, the catalytic converter is a sticking point. I'll eventually have to pass a strict emissions test. As a new car I do have a waiver for a number of years, but I'm a one-and-done kind of guy. So... I didn't learn until I already had the downpipe from China that there are also very few aftermarket cats that don't throw a CEL, even if they do pass emissions (not likely). If you live somewhere that you have no emissions testing, then by all means get the catless pipe with your dummy 02 sensor and life your life! Or if you do have emissions but you're willing to put the cat back after your grace period.

I was so bummed to not put it on - it's still sitting in the box in my garage. But since installing my custom axle-back, I'm in love with the way it sounds.


Good luck!

Good stuff! I reached out to ER to ask if they have tried fitting to the newer x1/x2 and roll report back. But based on what you said it’s unlikely. For now at least.

Luckily in FL there is no emission testing. U have been running catless on my other car forever.

I replied to your other exhaust thread. Would be curious for a photo of the new setup. Maybe an interior cabin driving video as well. Are you hearing any drone? Loud enough inside to justify the work?

[BabyX6]

Originally Posted by abirmaher

Good stuff! I reached out to ER to ask if they have tried fitting to the newer x1/x2 and roll report back. But based on what you said it’s unlikely. For now at least.

Luckily in FL there is no emission testing. U have been running catless on my other car forever.

I replied to your other exhaust thread. Would be curious for a photo of the new setup. Maybe an interior cabin driving video as well. Are you hearing any drone? Loud enough inside to justify the work?

Oh hell bro - I'll make you an interior video because of how damn amazing it sounds and I'd like to show it off. It's NICE. There is ZERO drone. At highway speeds, the exhaust noise disappears entirely. There's a nice low tone with the windows closed during acceleration. With the windows open it's WILD. Especially during acceleration, it sounds like a tie fighter exhaust bro. It screams.

[abirmaher]

Originally Posted by BabyX6

Oh hell bro - I'll make you an interior video because of how damn amazing it sounds and I'd like to show it off. It's NICE. There is ZERO drone. At highway speeds, the exhaust noise disappears entirely. There's a nice low tone with the windows closed during acceleration. With the windows open it's WILD. Especially during acceleration, it sounds like a tie fighter exhaust bro. It screams.

That sounds perfect. With that I don’t think I’d even need a downpipe.
But yes any interior vid and additional pics and details of the setup would be appreciated!

[BabyX6]

Originally Posted by abirmaher

That sounds perfect. With that I don’t think I’d even need a downpipe.
But yes any interior vid and additional pics and details of the setup would be appreciated!

I posted this in the other thread too, but here's the direct link to the exhaust photo:

https://u11.bimmerpost.com/forums/pi...ctureid=106474

I'll go grab an interior video here in a few, before it starts to snow :-(. I'll repost with the YT link.