Secondary Air Injection on late production 2006 L61's
 

Certain late production model 2006 and on Cobalts with L61 (2.2L) engines had an optional emmisions system called Secondary Air Injection (SAI) added to it. This is a control system that added fresh air to the exhaust manifold to help burn off unused gases from the engine prior to entering the catalytic converter. It was required for California emmisions and I think some New York stuff too. The issue caused problems for people wanting to use aftermarket intakes and manifolds due to the lack of provisions for the system. At present, K&N is the only aftermarket intake system that provides for SAI. There are no aftermarket headers at this time, and probably never will be.

SAI is not Exhaust Gas Recirculation (EGR). It is actually the exact opposite. SAI adds fresh air to the exhaust. EGR routes exhaust gas back into the induction. While the Ecotec originally had a casting provision in the cylinder head for EGR, it was never used on any known models. The provision was deleted in the 2005 model year, however certain parts of the orginal casting still remain evident on the current production head.

Here are older threads on the topic:
2.2 Header
LSJ Header
Air pump line
Header for 2.2
EGR Bypass
Intake installation
EGR installation
Header installation
Header installation

If you have the system, your exhaust manifold will have a mounting provision right on top center for the air valve.
https://www.cobaltss.net/gallery/fil...AImanifold.jpg

And you will have an extra line coming off of your air box.
https://www.cobaltss.net/gallery/fil...1Image0004.JPG

The system can be best explained with some pictures. Heres the Patriot Performance cylinder head with some highlighting:
https://www.cobaltss.net/gallery/fil...Ecotechead.jpg

You can see on top the old casting for EGR. It was never used. On the Cobalt, and all 2005 and later Ecotecs, this was removed. However, the entry passages are still there in the manifold flanges. They don't go anywhere, they are dead end holes. They probably left them there so they wouldn't have to change the manifold flange designs.

Air is circulated through the actual flange of the exhaust manifold. Here's what it looks like:
https://www.cobaltss.net/gallery/fil...Imanifold2.jpg

It gets around the exhaust ports via the cross over passages in the head, and is then directed at the back of the exhaust valves via the passages in the head.
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I would like to qoute a post that is later in the thread:
This technique has been verified as a legitimate method of deleting SAI from your car in a completely legal way, as long as you don't live in California (sorry West coasters!). You would require either an aftermarket intake and exhaust manifold, or a way to block off the plumbing on the stock parts, but it does work.

Here's a couple more pictures of the system from the top showing the line from the exhaust manifold.
http://memimage.cardomain.net/member...777_9_full.jpg

http://memimage.cardomain.net/member...77_10_full.jpg

wow i got one word for our exhaust manifolds......RESTRICTIVE!!

we are still looking for some one to send us in their set up , so we can fit it for our header

i work at pacesetter for those that dont know , and our offer for you buying a painted header and lending us your stock parts so that we can update a header for you guys with these , and getting a coated header in return , is still open

Ok i have this secondary air injection, is this a good thing or a bad thing? (other than the fact that they dont have headers for it yet)

ok, i have the SAI, and i changed my downpipe today... i had 2 Cats!! that's right, 2 of them...

Thats what i thought when i had my muffler installed that it looked like two but i wasint sure.

Resonator, not 2 cats

i don't think it's a resinator... so you're saying there's one resinator on the downpipe, that looks exactly the same as the cat, looks like a cat from the inside, and then there's a seperate on on the other pipe of the exhaust?

now that i think of it, i don't think that ANY model cobalt has a resinator on the downpipe... so what makes you think that this one is not a cat, and in fact is a resinator?

The cat is on the b pipe between the two oxygen sensors, the resonator is the long straight through muffler forward of the rear axle assembly.

:lol: i know what a cat is, and i know what a resinator is... i'm saying that i have 2 cats... on the downpipe, there are 2 cats... it's definately, 100% NOT a resinator...

look at your emissions lable , it will mention having 2 cats , main and a pre

if both what you can cats are on the down pipe , then its possible there is 2

if its after the flange then its a resonator

get pics

Yeah I have the SAI as well...and I have 2 cats also...didn't look like a resonator to me.

So back to my orginal question, is this good or bad that we have this?

I just peered under my buddy's 2.2 that has secondary air injection, and there is only one cat. If there were two, one would be mounted on the manifold, which would be good for emissions, but bad for HP and flow. having 2 cats reduces cold start emissions, because the warm up time (cat light off) is reduced.

I'll look at the plumbing diagrams in the morning and provide a better explanation.

hmm...maybe i have a freak of nature... pics will be up around lunch time

on my car, you were able to see one when you look underneath the car, and could see a different one when looking under the hood...

Looking at exhaust plumbing diagrams from service manuals there are definetly pictures of 2 cats on the pipe, with the 2nd O2 sensor between them. Doesn't mention anything about it, but its in the pics. I would have looked at the manual last night, but my intoxication prohibited it. ;)

yep... here it is.. can clearly see it's not a resinator:

http://i18.photobucket.com/albums/b1...g?t=1163963138

What would happen if I rendered my SAI system mute by deleting it on both the exhaust and intake. Say I purchased a GMPP intake (which i don't believe has a port for SAI) and an LSJ header. The SAI system would essentialy be gone, however would any issues arise from not having the SAI?

youll get a SES light , the intake side just sucks filtered air like the tb does , and youll fail emissions

the cobalts that have air injection do have two cats(as you can see from his pics). the one is an oxidizing and the other is reducing. the other cobalts that do not have the sai have only one cat. and oxidizing/reducing cat. (three way cat)

I believe the GMPP intake DOES have a SAI port.

id like to see a dyno run back to back on the same dyno of a SAI car and a non Sai

^^ I don't see why it would be any different... :confused:

it might not be...but its just somthing that intrests me

i don't have any evidence to prove it, but it doesnt' really do anything to affect performance... it's strictly for emissions, that's it...

Hmmm, that's not what happened to this guy:
https://www.cobaltss.net/forums/2-2l-l61-performance-tech-45/need-help-w-gm-intake-install-39193/

SAI issues
 

ok guys if u run an 06 balt that has SAI the only head pipe that u can run w/o setting ses light is the honed GMPP pipe. i spoke to a gmpp guy for 1/2 hour and he said that the honed manifold would work and not set a DTC for SAI aside from that you would have to flash the ecm to think it was a 05 model,then the ecm would not look for the O2 sensor to lean out at startup,also SAI only bruns @ start up to frie off unburned gasses in the cat

Well, that's not correct either. The GMPP manifold doesn't provide for the system, so you would have to delete it just like with any other manifold. Everything else is right, but it doesn't matter which manifold you use.

Sai
 

I also ran the part number against my VIN @ the dealer where i work usually if there was an issue with a GMPP part number not working in a vin specific search so maybe im getting told false info

Sai
 

also the GMPP manifold is in essance a stock manifold "honed" out so the bypass ports in the manifold should still be there. i will be purchasing one soon and will post my results on the install etc

yeah that would be VERY WRONG , and he had no idea what your talking about

the honed gmpp manifold is a cast iron manifold , and does not have the provisions for the AIR injection set up

look at the pictures in the first post and go find pics of the gmpp manifold , WAY different and wont work

Does it? I read on some other thread that it doesn't and the GMPP Intakes come with a note, "For 05-7 2.4's and 05 2.2's"

They cant just change shit half way through a production year and then not back it up (parts). WTF!!!

im not saying thats right that was the way gm explained it to me,the only way to find out is try it and wait for the SES light

Okay, two things

First, NEITHER the GMPP intake or exhaust provide for the SAI system. Case closed.

Second, I applaud your desire to delete the system by installing both, but to "wait and see if a CEL comes on" is never a good way to go about modifing. I can almost assure you it will turn on a CEL. I've simply not seen anybody try yet. As you mentioned, you should probably get a reflash from an earlier software version before SAI was installed in order for it to work correctly.

Now, if you do all three of those things (intake, exhuast, reflash), and you get a working car with no CEL, then that is GREAT news that people will want to know. So let us know too!

You'll definetly throw a SES light for any tampering with the AIR system. Probably a p2430, but there are others depending on what lines you disconnect. The entire system is monitored by a series of pressure sensors that compare actual pressure before and after the AIR pump to expected pressure. I believe there is also an I/M monitor for secondary AIR as well, which, you will never pass.

i don't know about all these sensors......its just running fresh air through, technicly not really emissions related unless the o2 sensor is calibrated to read higher levels of oxygen and not pull a lean code. If you dissabled the system it would read rich and cut fuel but ONLY if its being monitered. If it isn't then no worries. Has anyone contacted GM about this system? Maybe they can help us clear up the fog.....

ps. Nice VD link Witt lmao