What options for X1 35i high flow cat?

[BMWX1-35i]

Just what the title says, looking for options for catted high flow downpipes

[solidsleeper]

i believe any e9x n55 will fit

[solidsleeper]

I have a catted DP and started getting CEL for after 1 month. 2013 N55

[darkrom]

Go catless or stay stock. Either the cat is efficient and restrictive and makes no power, or it's free flowing and will fail emissions, in which case you're better off going full catless.

You can't have your cake and eat it too In this case. I'll eventually be going catless most likely just like my 135i.

[Chicone]

Originally Posted by solidsleeper

I have a catted DP and started getting CEL for after 1 month. 2013 N55

That’s good to know because I’ve been considering the catted downpipe option to avoid the CEL problem. How do you deal with them? Clear them every once in a while?

[solidsleeper]

Originally Posted by Chicone

That’s good to know because I’ve been considering the catted downpipe option to avoid the CEL problem. How do you deal with them? Clear them every once in a while?

w/ MHD (or any other tune) you can disable the CEL dash light for the cat deficiency code, but it will still fail emissions when I go in for testing in California (praying the code will magically disappear before testing). I'm able to clear the code with MHD / Protool, but after a 20 minute drive the code pops back up. I may experiment with a gallon of E85 or different gas station brands to see if that makes any difference, still have until Jan 2021 to mess around with it. Maintenance wise I want to say I'm up to date, but maybe I'm missing something.

[solidsleeper]

Originally Posted by darkrom

Go catless or stay stock. Either the cat is efficient and restrictive and makes no power, or it's free flowing and will fail emissions, in which case you're better off going full catless.

You can't have your cake and eat it too In this case. I'll eventually be going catless most likely just like my 135i.

Are you planning to remove the secondary cats as well?

I'm playing with the idea of going catless, but I'd also want to remove the secondary cats at the same time.

[darkrom]

Originally Posted by solidsleeper

Are you planning to remove the secondary cats as well?

I'm playing with the idea of going catless, but I'd also want to remove the secondary cats at the same time.

I believe the n55 only has primary cats and no secondary cats but I'm not totally sure honestly.

[solidsleeper]

Originally Posted by darkrom

I believe the n55 only has primary cats and no secondary cats but I'm not totally sure honestly.

https://e84.xbimmers.com/forums/show....php?t=1225624

there should be 2 secondary cats stock

[darkrom]

Originally Posted by solidsleeper

https://e84.xbimmers.com/forums/show....php?t=1225624

there should be 2 secondary cats stock

Damn just like my n54 135i. Yes I'd remove all cats once I go down that route.

[e36addict]

All N55 Xdrive cars have secondary cats, I assume due to the fact that the primary cat is smaller than RWD cars, since the subframe is in the way. I removed all 3 cats and did an MHD BEF. Problem solved.

[darkrom]

Originally Posted by e36addict

All N55 Xdrive cars have secondary cats, I assume due to the fact that the primary cat is smaller than RWD cars, since the subframe is in the way. I removed all 3 cats and did an MHD BEF. Problem solved.

How did you remove the mid pipe cats. Aftermarket mid pipe (who makes one for this platform) or cut them out and weld in piping?

[e36addict]

I just cut the old ones out and welded in two short sections of pipe. I got lucky and a buddy at my shop had some extra piping laying around.

[BMWX1-35i]

My only concern with removing the cats is exhaust noise and drone. I don't want it loud, matter of fact I have the exhaust valve disabled and that about as loud as I want it. Otherwise I would remove the cats.

[BMWX1-35i]

Originally Posted by solidsleeper

i believe any e9x n55 will fit

Does anyone know if this is true?

[solidsleeper]

Originally Posted by BMWX1-35i

Does anyone know if this is true?

I'm 99% sure all E9X N55 downpipes will fit.

Catted DP (stock mid & stock exhaust w/ exhaust valve closed)
I'm not even sure I'd call it drone, but there is a slight increase in sound at highway cruising speeds. For me it was noticeable for the first couple of drives, but I'm used to it now and there is no significant drone to negatively affect my morning commute. In city driving the X1 will still sound very tame with a catted DP and the exhaust valve closed.

With the exhaust valve open at maintained cruising speeds there isn't any added drone (compared to exhaust valve closed). There is a noticeable drone when accelerating on the highway with the exhaust valve open. I wouldn't say this drone is bad, but if I wanted to have a conversation with a passenger I would want to close the exhaust valve. In city driving there will be added drone and noise when starting from a stop, but not anything head turning.

Overall I am happy with how my car sounds (Wagner catted DP / Wagner EVO 1 IC / MHD 2+). With the valves closed, car is still low-key. If I'm feeling more ricer I can roll down my windows and open the exhaust valve.

Unfortunately I'm still throwing a CEL so that will be fun come smog time.