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      08-02-2018, 07:30 PM   #8
rho123
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Drives: 2013 128i - sold, 2007 Z4C
Join Date: Jan 2017
Location: Bay Area, CA

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Quote:
Originally Posted by rowsdower View Post
Quote:
Originally Posted by chris_flies View Post
As long as you keep the secondary cats, you might be fine with headers, but CA is brutal with mods...

About the tune, I'm not sure, as I have an N52 tuned by Active Autowerke (Turner). Good tune, but doesn't push any boundaries.
Secondary cats are behind the postcat O2 sensors and will not affect your ability to pass a smog check assuming it is an OBDII test. If you were going to fail without secondaries, you will fail with them. Some states that require emissions inspections will let you pass with 1 Not Ready system so you could theoretically get through inspection without primaries, though I do not have experience trying to do that. I do not know CA's laws but if there was any state that would not allow any Not Readys, it's CA.

I have AA headers and the BPC N51 tune and there is something wrong that nobody seems to be able to figure out, and the car won't idle well. If I could do it over again I would skip the headers and go with just a tune, or leave it stock. AFAIK the Bimmerlabs tune is only for the N52 with aftermarket 3-stage manifold - it is not for the N51 so your options are BPC or AA.
Quote:
Originally Posted by rowsdower View Post
Quote:
Originally Posted by chris_flies View Post
As long as you keep the secondary cats, you might be fine with headers, but CA is brutal with mods...

About the tune, I'm not sure, as I have an N52 tuned by Active Autowerke (Turner). Good tune, but doesn't push any boundaries.
Secondary cats are behind the postcat O2 sensors and will not affect your ability to pass a smog check assuming it is an OBDII test. If you were going to fail without secondaries, you will fail with them. Some states that require emissions inspections will let you pass with 1 Not Ready system so you could theoretically get through inspection without primaries, though I do not have experience trying to do that. I do not know CA's laws but if there was any state that would not allow any Not Readys, it's CA.

I have AA headers and the BPC N51 tune and there is something wrong that nobody seems to be able to figure out, and the car won't idle well. If I could do it over again I would skip the headers and go with just a tune, or leave it stock. AFAIK the Bimmerlabs tune is only for the N52 with aftermarket 3-stage manifold - it is not for the N51 so your options are BPC or AA.
Thanks for clearing that up.
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