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Charting O2 Sensor Voltage - Let's Beat the P0420!
- Thread starter poprocks01
- Start date
flipflp
Autocross Newbie
AWE downpipes have the same claim and can be had for about $800. They come with spacers and a better quality cat, thats about it.
Emmanuel Designs is whom you can purchase the downpipe from. Bull X made a downpipe that doesn't throw a CEL (no spacer needed), for the MK7, and it seems to be quite popular.
I just find it incredible that none of the makers for our platform, (in particular for the CBFA engine) have been able to make a downpipe that doesn't throw a CEL without the need for a spacer.
I'd be willing to pay more, especially with emissions being so stringent in the Northern Virginia area. Otherwise, I would've been stage 2 ages ago...
I just find it incredible that none of the makers for our platform, (in particular for the CBFA engine) have been able to make a downpipe that doesn't throw a CEL without the need for a spacer.
I'd be willing to pay more, especially with emissions being so stringent in the Northern Virginia area. Otherwise, I would've been stage 2 ages ago...
flipflp
Autocross Newbie
I hate repeating myself one post down but AWE has been making a downpipe for sometime now that they guarantee will not throw a CEL.
Here, I'll even post a link!
http://www.awe-tuning.com/make/volkswagen/cc-2-0t-exhaust-system
:readthethread:
Just to clarify this DP does come with spacers, but ones that AWE has engineered to work under their guarantee. Also Mk6 to Mk7 is a bit different as far as number of cats, etc. The Bull X downpipe has 2 high quality cats, similar to stock. It probably doesn't flow as well as other options but it works.
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Yes, I understand that AWE has one for our platform, and I thank you for posting the link for me to check out.
I was just pointing out how we'll need spacers for MK6 aftermarket downpipes, and companies (AWE, Neuspeed, Bull X) have managed to engineer downpipes for the MK7 that don't need or use spacers. I'm not sure if they decided to invest more money to make this a reality, I don't know. Just making a point of something I've noticed. The MK7 downpipes cost most money, but it must be nice not having to sweat bullets during emissions testing.
I also read sometime ago on this forum (a post from Unitronic), that spacers will eventually affect the long term fuel trims. I wonder how true that is.
Wideopentuning
Ready to race!
The cat used in the AWE downpipe is quite expensive since it has more precious metals and as such, catalyzes well enough to typically keep the ECU happy. It's not the same sub $100 cat used in a lot of the others.
flipflp
Autocross Newbie
A lot of differences between the Mk6 and Mk7 engines and control systems, so I don't think they can be compared. It still stands that you'll need to either give up flow with a higher cell count cat or use multiple cats. Spacers allow you to avoid that cost and restriction, but are a bit fiddly.
If you're going to be sweating bullets at emissions testing then you should keep your stock downpipe and swap back with a tune that does not disable O2 sensors. Then you can't get dinged on visual either, which would be a failure if the smog tech looked at your downpipe. That's my plan for when that time comes.
Also I don't think putting spacers on the 2nd or 3rd O2 sensor would effect fuel trims. Pretty sure only the 1st O2 right off of the turbo gives a/f lambda feedback, the other two are for measuring catalyst efficiency, which is why they need to be tricked.
Hello my good people, I managed to defeat the p0420 and p013 on my CBFA engine with much trial and error.
Long story short, I ended up using an Aliexpress J spacer with the smallest insert in it on the 3rd o2 sensor. And the Doorman 42009 spark plug non-fouler (had to drill it out like everyone else) with a total of six 18mm washers to space it out a little bit more (MOST IMPORTANT PART FOR ME).
My setup:
K04 Turbo
Arm Motorsports catted downpipe
IE stage 1 tune (to pass catalyst)
So for people who need more context on this problem. The 2nd o2 sensor (before the second catalytic converter) is really picky on the signal that it receives to pass the catalyst test because the OEM downpipe has two catalytic converters, the first one is at the face of the turbo and the second one is between the 2nd and 3rd O2 sensors. If the 2nd O2 sensor sees too much dirty exhaust P0420
, too little exhaust P013. The 3rd sensor is not much of a problem all it wants to see is a clean signal from the exhaust. It seems that many different people have had a bunch of different success stories with different setups on the CBFA engine which is strange. But the main culprit is the 2nd o2 sensor, you'll need to find the right spacing for it to be happy. For me, just the spark plug non-fouler without any washers threw the P0420 code. Using two sparkplug non-fouler staked up threw the P013. So it became clear to me that there was a sweet spot between 1 sparkplug non-fouler and 2 stacked up I just had to find it.
Long story short, I ended up using an Aliexpress J spacer with the smallest insert in it on the 3rd o2 sensor. And the Doorman 42009 spark plug non-fouler (had to drill it out like everyone else) with a total of six 18mm washers to space it out a little bit more (MOST IMPORTANT PART FOR ME).
My setup:
K04 Turbo
Arm Motorsports catted downpipe
IE stage 1 tune (to pass catalyst)
So for people who need more context on this problem. The 2nd o2 sensor (before the second catalytic converter) is really picky on the signal that it receives to pass the catalyst test because the OEM downpipe has two catalytic converters, the first one is at the face of the turbo and the second one is between the 2nd and 3rd O2 sensors. If the 2nd O2 sensor sees too much dirty exhaust P0420
, too little exhaust P013. The 3rd sensor is not much of a problem all it wants to see is a clean signal from the exhaust. It seems that many different people have had a bunch of different success stories with different setups on the CBFA engine which is strange. But the main culprit is the 2nd o2 sensor, you'll need to find the right spacing for it to be happy. For me, just the spark plug non-fouler without any washers threw the P0420 code. Using two sparkplug non-fouler staked up threw the P013. So it became clear to me that there was a sweet spot between 1 sparkplug non-fouler and 2 stacked up I just had to find it.Attachments
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