cp-e™ SS Cat Back System

[jtsherri]

Originally Posted by Kit523

I have the same exhaust but on a 335i
love every bit of it!!!!!
perfect fit and finish!!!
CP-E FTW!

Damn right.

[andrew777]

Just got this installed today. I've got an auto and have catless dp's so all I can say is holy fucking drone. It is really bad. The only good thing is that if you cruise around the highway in sport mode you will avoid it completely. Otherwise, your ears will be ringing its so bad.

It sounds great otherwise. Much louder than stock, but won't drive the neighbors insane. Sounds amazing when engine braking. Love the burbles.

[jtsherri]

Originally Posted by andrew777

Just got this installed today. I've got an auto and have catless dp's so all I can say is holy fucking drone. It is really bad. The only good thing is that if you cruise around the highway in sport mode you will avoid it completely. Otherwise, your ears will be ringing its so bad.

It sounds great otherwise. Much louder than stock, but won't drive the neighbors insane. Sounds amazing when engine braking. Love the burbles.

Ha - yep, exactly. I've *still* yet to get resonators installed, but anyone that's been in the car (and has experience with resonators) has said they'll work wonders.

I guess I've just gotten used to it and know what RPM-range to keep the car in to keep it tolerable; however, I will get some installed soon.

[andrew777]

Can't wait for you to make the switch and give some feedback

BTW does cp-e sell the resonators alone? How hard is the install? Can't seem to find much on it.

[Mutilator]

I have the resonated version and the drone nearly drove me insane early on which forced me to start using DS mode which I hadn't really used much up until that point. The drone does gradually die down after 500-1000 miles but doesn't go away completely - you just kind of get use to it when cruising up hill in 6th gear, or drive in DS mode which just about avoids it completely - plus as mentioned you get to hear the wonderful sounds while downshifting. Weather seems to play a role in the exhaust tone as well.

I had a shop install my exhaust but I was under the car helping/watching the whole time - it wasn't that difficult since we had the car up on a lift - don't see why you couldn't do it on some jack stands in the driveway if you had to as long as you bring a little patience.

As for the resonator I would imagine they could sell you one and you have your local shop weld it in... or you may be able to just get one from your local shop.

As for the exhaust itself I've had it on the car for oh... over 15,000 miles now and I still love it. Eventually I'll let someone else drive the car without me in it so I can hear what everyone else hears from outside the car. So far the closest I get is when I punch it while driving under an overpass... damn I love that sound.

[ennislaw]

Originally Posted by jtsherri

Ha - yep, exactly. I've *still* yet to get resonators installed, but anyone that's been in the car (and has experience with resonators) has said they'll work wonders. ... .

I'll be purchasing the cp-e catback system come January when my 135 (manual trans) makes it here for a PCD. I still have been unable to determine how many decibels the resonators will lower the sound on the catbacks, and whether I should include them in the order. It's nearly impossible to tell from the videos, and I've seen them all, believe me. And unfortunately, cp-e doesn't have any info about how many decibels their resonators cut. I really don't want to order the system, then have to go the trouble (and expense) of having resonators installed afterwards.

I blame jtsherri for all this, it was his videos!!!

[jtsherri]

Originally Posted by ennislaw

I'll be purchasing the cp-e catback system come January when my 135 (manual trans) makes it here for a PCD. I still have been unable to determine how many decibels the resonators will lower the sound on the catbacks, and whether I should include them in the order. It's nearly impossible to tell from the videos, and I've seen them all, believe me. And unfortunately, cp-e doesn't have any info about how many decibels their resonators cut. I really don't want to order the system, then have to go the trouble (and expense) of having resonators installed afterwards.

I blame jtsherri for all this, it was his videos!!!

Ha - sorry!

The cp-e system isn't obnoxiously loud, by any means; however, it *does* scream pretty good under wide-open throttle . I would highly recommend opting for the resonated system if the volume is a concern.

[andrew777]

I just took a nice 2 hour trip on the he to visit a friend. The drone is unbearable. Need to do something to fix it. Resonators seem like a pain. I might just try putting the stock muffler back on.

[jtsherri]

Originally Posted by andrew777

I just took a nice 2 hour trip on the he to visit a friend. The drone is unbearable. Need to do something to fix it. Resonators seem like a pain. I might just try putting the stock muffler back on.

It can definitely be a pain (that's why I'm recommending that others order the exhaust with resonators)... But it really all depends on how much you like the sound of the exhaust. I personally wouldn't part with mine.

Also, keep in mind that you don't necessarily have to send the exhaust back to cp-e to have this done. There's always the option of ordering some resonators on your own and having an exhaust shop weld them in.

[jibaholic101]

hmmmm....

i am wanting to order, but now am on the fence

i have a 6MT car and wanted to end up without the resonators as i love the volume and the exotic sound, however, i dont want to destroy my eardrums with a system that is droning too much.

i might get DPs in the future, but am not sure at this point. is there anyone out there with 6MT with DPs and no resonators?

i am on the fence what to do because part of me wants the system to be loud and aggressive because that is what i have always wanted, but the other part doesnt want my exhaust to annoy me.

HALP!

[jtsherri]

I recently spoke with cp-e about this and they recommended having 2-3 1/2" dowels welded evenly between the two midpipes to eliminate the droning. I haven't had a chance to do this yet, but it makes A LOT of sense, as the droning occurs as a result of the midpipes creating a 'tuning fork' effect of-sorts.

Apparently this has corrected the issue for at least 2 other customers already, so you may get in contact with them to find out if this is a change they've made in the newer systems they're shipping out.

[Mutilator]

Originally Posted by jtsherri

I recently spoke with cp-e about this and they recommended having 2-3 1/2" dowels welded evenly between the two midpipes to eliminate the droning. I haven't had a chance to do this yet, but it makes A LOT of sense, as the droning occurs as a result of the midpipes creating a 'tuning fork' effect of-sorts.

Apparently this has corrected the issue for at least 2 other customers already, so you may get in contact with them to find out if this is a change they've made in the newer systems they're shipping out.

This is close enough to replying to the PM I sent you...

Anyway, since cp-e is closed until the 3rd I believe I'll check with the shop that installed my exhaust and/or another local BMW tuner and see if they agree that this is worth a try. If so then I'll probably get it done ASAP. Cars aren't meant to be tuning forks... even if it is in a very small RPM band.

[jibaholic101]

Originally Posted by jtsherri

I recently spoke with cp-e about this and they recommended having 2-3 1/2" dowels welded evenly between the two midpipes to eliminate the droning. I haven't had a chance to do this yet, but it makes A LOT of sense, as the droning occurs as a result of the midpipes creating a 'tuning fork' effect of-sorts.

Apparently this has corrected the issue for at least 2 other customers already, so you may get in contact with them to find out if this is a change they've made in the newer systems they're shipping out.

i will be contacting them about this.....

they are currently out of stock for the exhaust anyway....

makes sense, but why wouldnt they just do it to begin with in production?

[jtsherri]

Originally Posted by Mutilator

This is close enough to replying to the PM I sent you...

Anyway, since cp-e is closed until the 3rd I believe I'll check with the shop that installed my exhaust and/or another local BMW tuner and see if they agree that this is worth a try. If so then I'll probably get it done ASAP. Cars aren't meant to be tuning forks... even if it is in a very small RPM band.

Did you not get my reply? I even sent a make-shift diagram...

And I most-definitely think it's worth a shot... It makes absolute sense based on what I've experienced. And I can't believe it'll cost more than $50 (on the high-end) to get this done.

I'm still going to have resonators installed, but not because of droning. I absolutely love the sound as-is, but my driving style makes me a target with a loud exhaust... So I'm looking to tone it down a bit.

Originally Posted by jibaholic101

makes sense, but why wouldnt they just do it to begin with in production?

I'd ask cp-e when you're able to talk to them, but here's my take:

Based on my understanding, the exhaust was developed for a manual transmission car and I was the first person to install it on a Steptronic. Apparently the droning isn't nearly as bad on a manual, so I'm sure varying RPM and/or gears made it easy enough to avoid on the test vehicle. Up-until a couple of other customers reported it being more of an issue than they'd previously thought, I'm sure it never crossed their minds to modify the design.

Just my $.02 though.

[jibaholic101]

since it is designed for 6MT and i am part of that club, my worries have bbeen eased!

[jtsherri]

Originally Posted by jibaholic101

since it is designed for 6MT and i am part of that club, my worries have bbeen eased!

Awesome - just be sure to give them a call. I have no doubt that you'll love the sound and quality as much as I do, but you should make sure the droning isn't an issue if it's been a major concern of yours.

[escobar929]

jib, update this thread after you talk to cp-e. i was thinking bout calling them for the same thing, so no reason for a bunch of people to bother them w/ the same question

[ennislaw]

Originally Posted by escobar929

jib, update this thread after you talk to cp-e. i was thinking bout calling them for the same thing, so no reason for a bunch of people to bother them w/ the same question

As a potential buyer for the cp-e system, I certainly would be interested. Although I have a MT (well, will have as soon as the PCD comes through), most of my driving will be around the 2k-2.5k rpm range, so drone is a major concern.

Thanks!

pge

[jibaholic101]

Originally Posted by escobar929

jib, update this thread after you talk to cp-e. i was thinking bout calling them for the same thing, so no reason for a bunch of people to bother them w/ the same question

will call after the new year and post an update

[My135]

Did CP-E have just 1 instead of 2 hangers to attach the tail pipe to the body? I heard some one who had CP-E complained about the tips did not level with the bumper after the exhaust was warm up (like the tips were tilted). Any one notice the same thing?

[ennislaw]

Originally Posted by My135

Did CP-E have just 1 instead of 2 hangers to attach the tail pipe to the body? I heard some one who had CP-E complained about the tips did not level with the bumper after the exhaust was warm up (like the tips were tilted). Any one notice the same thing?

If anyone knows it's JT; as I understand it, he started with the cp-e catback (really downpipe-back as the secondary cats are removed by the midpipes) and then added cp-e downpipes later (and added resonators). Also, Mutilator has the cp-e downpipe-back system with resonators. Both have AT and a fair amount of miles with their respective cp-e system. If you search 1Addicts, JT has a whole writeup of the first installation with lots of photos and videos.

pge

[jtsherri]

Originally Posted by My135

Did CP-E have just 1 instead of 2 hangers to attach the tail pipe to the body? I heard some one who had CP-E complained about the tips did not level with the bumper after the exhaust was warm up (like the tips were tilted). Any one notice the same thing?

I've had ZERO issues with this. I could see where some *could* run in to this issue if they didn't tighten up the rear section of the exhaust enough, but that would be more of an installation error than anything. You are right with regards to the system having only 1 hanger though. When I first installed it, I'll admit that I was concerned; however, after quite a few miles, it's NEVER been a problem. My tips always sit perfectly level - hot or cold.

Originally Posted by ennislaw

If anyone knows it's JT; as I understand it, he started with the cp-e catback (really downpipe-back as the secondary cats are removed by the midpipes) and then added cp-e downpipes later (and added resonators). Also, Mutilator has the cp-e downpipe-back system with resonators. Both have AT and a fair amount of miles with their respective cp-e system. If you search 1Addicts, JT has a whole writeup of the first installation with lots of photos and videos.

pge

Actually, this is the thread you're referring to.

And this is all true, except I don't have resonators (yet). And I believe I'm nearing 10,000 miles on the exhaust and still absolutely love it! I started out with their first, non-resonated, production cat-back system and then later added non-catted downpipes. So in reality, I have a fully non-catted turboback exhaust. It's probably the most free-flowing exhaust on the market that's built by a single company, as there are minimal bends and restrictions. The only thing that could probably out-flow this thing is cp-e downpipes & midpipes and a Berk axleback - keep in mind that this which would be INSANELY LOUD, as it would basically be straight-pipes all the way from the turbos.