this is the downpipe for my auto 2.2 that i got from ZZP i ordered it with an extra o2 for wideband when i eventually get it tuned..
now my question is, which one is which for the o2 sensors and which one do i plug up?
1, 2 or 3
im guessing #1 is an o2 slot i need and does it matter which one i plug up? (2or 3)?

 

Why is there 3?

 

#1 will be your downstream o2 sensor.. I'm confused as to which #2 / #3 is wideband/does it matter.

 

I asked for the extra bung for wideband and there was only 2 on my dp

 

mine is an auto Chevy HHR not cobalt..we got out o2 sensors on the DP so the extra one is wideband, just not sure which one to plug up

 

I think it's the same for cobalts.

 

Chevygirl, yours is a 2.4. This is a 2.2 DP. #1 is the rear O2 sensor hole. #2 is the original front O2 sensor hole. #3 is the wideband hole.

 

so im gona guess that 2 and 3 dont matter which gets plugged up..just depending on placement and original
o2 sensor placement/wire length

 

Exactly.

 

hooked it all up today..the zzp downpipe makes it more raspy..no check engine light until a few hours later what should i do about it? just get it cleared?

 

If you get it cleared it will just come right back on. You'll need to tune it out if you want it to stay off. I just ignored the light until I could buy HPT and tune it out. Or you can do this:

https://www.cobaltss.net/forums/how-...w-cats-104703/

 

I just bought that $30 Vibrant O2 sensor defouler. Works like a charm.

 

im gona try the defouler from vibrant put an order thru thanks

 

Get a tune

 

i still got warranty so not sure if i want a tune just yet lol

 

i had the infamous P0420 code. my buddy disabled cel on hpt and it made it so my o2 was not "ready"
so i got the 30 $ vibrante o2 defouler enabled that code on hpt tables and it worked like a charm

 

alright guys im kinda getting worried here..more and more digging around and im finding more people with issues with the zzp downpipe, and like some have said the cat might be faulty. I cleared the p0420 code but it keeps coming back..isnt this going to be an issue with emissions tests?? We have pretty demanding tests here in Canada.. Even with a tune, some people are still having problems with the code coming back..this i find ridiculous considering the issues its causing and makes me not want this dp anymore, might as well use my stock one and not have problems..
thoughts??

 

Could just change it to stock for the test then put it back on afterwards.

 

ya that is an option..
but id like to just do something once and leave itm not having to switch back and forth..

 

I ordered my ZZP 2.5 back in March. Installed it with a Vibrant angled bung and haven't had a P0420 since.

ZZP now offers to weld in the angled o2 bung.

 

so im looking at getting a tune...and i did order a defouler..so my question is - when i finaly do the tune, should i keep the defouler on? or should i remove it and put the o2 back where it was originally? or does it not matter?

thanks

 

If you're getting a tune, get the rear o2 codes deleted.

 

can someone explain to me why with this new downpipe im burning soo much more gas? i get about half of the mileage on a full tank that i used to get before..i would get about 550-600kms full tank and now i barely get 300..
Will this tune correct this and will i get my mpg back?

 

Yeah a tune will probably improve your mileage. But also make sure you don't have a leak somewhere, especially where the downpipe/header bolt up. An air leak there could make your car think it's burning lean when it's really not, then make it dump fuel into your motor.