Best Catted N55 Downpipe

[VroomVroomRaceCar]

I'm looking to upgrade the downpipe on my 2011 135i but want to keep it Catted for emissions testing here in upstate New York. What works out there besides Cobb ($850)? Any advice on the pipe, install or lifetime?

Ryan

[Enovoc]

Originally Posted by GallagherRyanJ

I'm looking to upgrade the downpipe on my 2011 135i but want to keep it Catted for emissions testing here in upstate New York. What works out there besides Cobb ($850)? Any advice on the pipe, install or lifetime?

Ryan

Wagner tuning has one for $790. Also AR designs for $835. You can probably find out a diy install on here I cant speak for lifetime however. Btw I visited saratoga springs last week and its a beautiful town.

[Cavpilot2k]

I have had my eye on the cp-e catted DP for a while. It's expensive (>$1000), but it is a 5-inch pipe. My thoughts are that it would partially offset the obstruction of the cat by sheet volume.
Yes it has to neck back down after the cat (they all do), but a 5" pipe offers almost 3x the flow volume of a 3" pipe (based on the area of a 3" circle vs. a 5" circle).
When I am ready to go that route, that is the one I will choose. cp-e is expensive, but their stuff is absolutely top-tier.

[Ultimateone]

IMO Cobbtuning makes some of the highest quality exhaust parts out there.

[e36addict]

Installed an AR catted DP a while ago on a customer car. It was a very nice piece, and fit very well. Only issue was the rear oxygen sensor is placed a little further downstream, so the electrical connection for it is unable to sit in the correct bracket. Not a big issue, but other than that fit great and sounded really nice!

[Cavpilot2k]

Oh, and
In before the naysayers tell you not to waste your time and money with a catted DP!

[aloksatoor]

So does every catted aftermarket downpipe pass sniffer tests in CA (say with valet mode set or tune removed)? I am guessing the cpe does with its 5 inch diameter cat.

[Cavpilot2k]

That's hard to say. It may be worth asking each mfr.
I have read quite a bit (not manufacturer marketing hype, but neutral observations) that aftermarket cats often clean better than OEM cats despite having better flow because of better/more expensive catalyst materials.
I cannot back this up with any hard data at the moment though.

[kirkbar]

I just installed the Cobb DP on my 2011 135i. Switched map to Stage II+ aggressive. The car pulls MUCH harder. Cold starts are loud and so is WOT but cruising is civil.

I had a 08 135i with N54 before my N55 with a catless DP and JB4 and now feel the N55 is up to par with my old (RIP it was totaled) car.

[mike@x-ph.com]

Lots of good options.
Cobb, AR, CP-e