Downpipes, Tuning, and Inspection
02-01-2019, 01:44 PM
#1
Downpipes, Tuning, and Inspection
I bought a 2015 C400 last July and warranty is officially up so the mod bug is starting to bite. Besides some visual mods, first item is a tune.
I have done a ton of research here on the forums and I can't seem to find any concrete testimonials on what I'm looking for. At first, I was not planning on going the Stage 2 + DP route but then I watched some Youtube videos..
Stage 2 would prevent the car from throwing a code for the rear O2s but would show up as "Not Ready" or "Failed" for the readiness test during inspection. From my previous car and research I did at the time, Massachusetts would allow at most one (possibly two?) "Not Ready" readings and still pass inspection. If that's still the case, I imagine I could still pass inspection if readiness shows complete for everything except for the O2s. As I see it, I have three options:
1) Request a stage 2 tune with the rear O2 sensors ON and use an O2 spacer. This worked for my brother's turbo Jetta several years ago. I haven't found anyone on here claiming a spacer works for them and my fear is newer MB cars are too smart for this quick fix.
2) If I get a CEL despite the spacer, I could roll the dice and switch the tune to have the O2s OFF and see if I can get away with failing O2 readiness.
3) Uninstall and reinstall the DP and tune each year for inspection. I'd like to avoid this. I heard its not too complex but working on my bro's Jetta, bolts near turbos can be finicky and difficult to work with due to the constant transitions from extreme heat to cold.
I could just give up my plans for a DP and just go Stage 1 and call it a day. Though worst case scenario if 1 or 2 don't work and I don't want to reinstall, I could resell the DP and go stock exhaust with Stage 1.
Obviously all of this would require a tuner that is willing to work with me as I try different options, hopefully not at a huge expense for me.
EDIT: I confirmed I can fail only 1 readiness monitor and still pass. Which readiness monitors would show as not ready after tuning out the rear O2s?
I have done a ton of research here on the forums and I can't seem to find any concrete testimonials on what I'm looking for. At first, I was not planning on going the Stage 2 + DP route but then I watched some Youtube videos..
Stage 2 would prevent the car from throwing a code for the rear O2s but would show up as "Not Ready" or "Failed" for the readiness test during inspection. From my previous car and research I did at the time, Massachusetts would allow at most one (possibly two?) "Not Ready" readings and still pass inspection. If that's still the case, I imagine I could still pass inspection if readiness shows complete for everything except for the O2s. As I see it, I have three options:
1) Request a stage 2 tune with the rear O2 sensors ON and use an O2 spacer. This worked for my brother's turbo Jetta several years ago. I haven't found anyone on here claiming a spacer works for them and my fear is newer MB cars are too smart for this quick fix.
2) If I get a CEL despite the spacer, I could roll the dice and switch the tune to have the O2s OFF and see if I can get away with failing O2 readiness.
3) Uninstall and reinstall the DP and tune each year for inspection. I'd like to avoid this. I heard its not too complex but working on my bro's Jetta, bolts near turbos can be finicky and difficult to work with due to the constant transitions from extreme heat to cold.
I could just give up my plans for a DP and just go Stage 1 and call it a day. Though worst case scenario if 1 or 2 don't work and I don't want to reinstall, I could resell the DP and go stock exhaust with Stage 1.
Obviously all of this would require a tuner that is willing to work with me as I try different options, hopefully not at a huge expense for me.
EDIT: I confirmed I can fail only 1 readiness monitor and still pass. Which readiness monitors would show as not ready after tuning out the rear O2s?
Last edited by Italianxmna89; 02-01-2019 at 02:23 PM.
