[Senpai]

If anyone here is interested I have a used full cpe catback exhaust. It's a full 2.5" all the way back and fits xi! Pm me if you're interested!

[npowered]

*begin post resurrection* Good news for a 3.5" option for XI owners!

I just had my local shop install an aftermarket exhaust on my 08 e90 xi. I had been communicating with Dave@ATM (https://www.atmspeedshop.com/) atm@atmspeedshop.com and was willing to test their new 3.5" race exhaust they have been working on for a while. They have designed it for RWD, but I asked them to send me one even though I'm AWD and I'd let them know if it fits and what needed to be modified (if anything). The thought was to be able to make a slightly different model to sell to us XI owners.
Turns out, and despite the massive 3.5" piping, the system fit perfectly. The only thing that wasn't used was a bracket that connects to the tranny as the transfer case was present.

From the shop (Harrison Motorsports):

This is Sergio Ramirez from Harrison Motorsports, I wanted to provide and update for the 3.5 race exhaust we installed in Darren's 335xi. The install was pretty straight forward no custom fabrications was needed, it took a lot of adjustment and the clearances were a bit tight in some areas, but it was a straight forward bolt on job. The only bracket we were unable to use is the one that attaches to trans in center section due to transfer case, but we tested exhaust multiple times in different conditions and temperatures and found the exhaust held strong no signs of needing the extra mounting location. Below you will find a link to all the pictures we took and a video, if you have any more questions feel free to contact us thank you. https://www.smugmug.com/gallery/n-LrQzbG/i-9khpGxN/A

There is not any information on the exhaust yet on ATM's website, but there is a post on $P00L$TR33T. Google "ATM 3.5 exhaust" and it's a few links down the page.

Here are some great features (edited by me for brevity) and subject to change:
1) Flex-joints in the downpipe flange area section. This accomplishes 2 things:
a) Improves ground clearance
b) Allows for variance in downpipe fitment - one of the test cars we tried had downpipes that fit like crap (flanges were uneven and would not allow the previous rigid design to bolt up). If we came across this that means customers will too. Flex-joints in the front section solve this issue.

2) Slip-joint at the front-to-midpipe section. This area is the 2nd worse section for ground clearance, the previous V-band here is basically a straight lip waiting to catch something. Changing this connection to a slip-joint gives another 5/8"+ of ground clearance in this area.

3) The rear section will use a V-band on the 3.5" single connection but slip-joints on the 3" sections at the tailpipes. We did this for several reasons:
a) Adjustability for installation. V-bands are great (they will be used in all other areas of the system) but just don't allow for enough adjustability. Perhaps you have a custom valence or your bumper is aftermarket. With the previous design everything better be perfect or the tips will be off. Not anymore....full adjustability left to right and up and down with slip-joint connections - This is huge. You can get the exhaust to fit perfectly with the right adjustment in several areas.
b) More tailpipe options. If you decide to change tailpipes, change your valence and go to quads, etc, it will be as easy as buying the 90 degree bends, cutting and swapping out. Again you are not limited to using the exhaust's V-band tailpipes or needing a fabricator to weld you up new tailpipes. This will bring more possible options to the end user Again, this is awesome and adds to the longevity of the system.
c) Muffler options. Slip-joint connections make future sound-deadening options easier. We plan to offer several methods for mufflers in the future, one being inline spiral mufflers that are easily replaceable in the rear section (will kill several decibels) and another being a rear muffler/Y-pipe. Our goal is to make these all independent of one another so that they can be used individually or in a combination to adjust the loudness.

The system looks and sounds amazing. IMO, the noise is not bad. I went from stock to this so it's a big bump in sound volume, but there's no droning. Only a change in resonation between 2.5k and 2.9k. On WOT, this thing sounds freakin' amazing from 5k - 6k. Startup is quite loud due to cold start, but I can make it quite a bit quieter during partial throttle.

Obviously, my opinion is just that and my observations are subjective. Full transparency, I did receive a discount on the exhaust (thanks Dave!), but only to make up for what a shop would charge for an install and any mods if necessary. TLDR; this isn't a freebie, fan boy review.

I have MMP3s on 25lb and e50 so next step is to get back on the dyno and see if it opened them up a bit. And tweak my tune.

Thanks for reading and I hope we can get more XI owners with as great an exhaust as I have around the country.

[Blaze439]

Any idea when it will be available?

[npowered]

Dave@ATM said he has a few pre-production sets in house, but not sure when they are going for full production. Since the only difference between the RWD and AWD fitment is not using just one of several brackets (this one is supposted to bolt on where the transfer case sits). They haven't tested fitment for E92, but confirmed perfect for e90 and e90 xi.

[scrllock]

Did they have any issues clearing the rear chassis brace?

[levirtehpwn]

Wondering if anyone has ever tried putting on active autowerk headers combined with race pipes. Or just race pipes to delete the secondary cats. Very curious about that.
Here is the link yonthebones I have in mind, its says in the description that it doesn't fit XI models. Still curious though... thanks!!
https://afepower.com/afe-power-49-36...-pipe#overview

[Yangorang]

I had the BMW PE 18102208793 installed on my 2008 328xi and love it.