[hokiedood]

I'm looking for catted downpipes that will pass OBDII California smog tests. Does anyone know a brand that will pass?

I also would like to know the performance gain for those downpipes. Would they also be enough to run the Bootmod3 map 2 tune on 91 octane?

[Logicoeur]

Only two guaranteed to fall within the oem o2 delta is the Fabspeed catted downpipe, and the HJS 300 cell dp, which is what is used in the Fabspeed product. Performance gains with any of them will be around the same, until a tune is added. Then that varies even more between the PWG and EWG turbos of the N55.

[mike@x-ph.com]

Originally Posted by Logicoeur

Only two guaranteed to fall within the oem o2 delta is the Fabspeed catted downpipe, and the HJS 300 cell dp, which is what is used in the Fabspeed product. Performance gains with any of them will be around the same, until a tune is added. Then that varies even more between the PWG and EWG turbos of the N55.

Fabspeed does not offer B58 downpipes

[Jayf30]

I don't have an answer to your question but if changing out downpipe is an option it should take max 2 hours on your first try and 1 hour or less after that. Definitely helps to have an extra pair of hands tho.

I usually shy away from doing any work under the hood in fear that I'll break something but I'm glad I challenged myself to see the project through and now am extremely familiar and comfortable with doing the work now.

Either way, good luck!

[G.Newt]

CG DS-1 5" catted downpipe. It's much pricier now than when it first came out, but it's because they also use high quality cats. Lot of us running it without CELs.

https://www.ecstuning.com/b-cg-preci...e/0005ds1~cgp/

[Logicoeur]

I'm guessing on the web it shows he has a b58? Can't see anything on mobile.

[sewhelan9]

I went with the HJS 300 cel catted downpipe from Mike @ x-ph for this very reason, I did not want to mess with spacers, CELs, failed emissions, etc. Paired with the MHD stage 2 tune, AP intake and DINAN mid-pipe, my 440i is now a transformed car and way more fun to drive and sounds amazing, even with the stock muffler.

[hokiedood]

Originally Posted by Logicoeur

I'm guessing on the web it shows he has a b58? Can't see anything on mobile.

I'm posting to the B58 forum so it should be implied.

I don't know if the mobile version shows which forum.

[Logicoeur]

Originally Posted by hokiedood

I'm posting to the B58 forum so it should be implied.

I don't know if the mobile version shows which forum.

Wow yeah it doesn't. I probably found this thread via New Posts

[hokiedood]

Originally Posted by G.Newt

CG DS-1 5" catted downpipe. It's much pricier now than when it first came out, but it's because they also use high quality cats. Lot of us running it without CELs.

https://www.ecstuning.com/b-cg-preci...e/0005ds1~cgp/

Do you know if my 340i will pass California OBD-II smog tests with those downpipes?

[G.Newt]

Originally Posted by hokiedood

Do you know if my 340i will pass California OBD-II smog tests with those downpipes?

Mine doesn't trigger a CEL, so I assume it meets BMW emission specs.

But, I'm not sure if the DP is CARB approved or not. I would highly recommend double checking your local emission laws.

[Cozmo Kraemer]

Originally Posted by hokiedood

Do you know if my 340i will pass California OBD-II smog tests with those downpipes?

No downpipe in CA will pass the visual inspection if they look. It could pass the sniffer test if they administer it to cars this new (I actually don't think they do). But the answer is almost always no for the visual. That being said, you could find a 'friendly' tester, or remove/reinstall stock DP for the test.