Exhausted my search about exhaust (and AIV PAIR valve)

[doctorsound]

In the middle of doing a new timing chain and I had thought I needed to get this out of the way from the down pipe. (I was wrong) What is this called so I can replace it. Or, I'm looking at a new header (Like so http://www.ebay.com/itm/240SX-180SX-S13 ... 3873wt_912) and it doesn't even have a place for it. Is this necessary?

In addition, I can't seem to find a writeup about the AIV pair valve removal anywhere that still has pictures. Is this something I can just remove completely if I do a new header (and an intake)? Is there parts that need to stay/be plugged?

I take it I still need what is in the below image. The headers I'm looking at still have a port to hook this up.

I really appreciate any and all help. I'm a little panicy over here, this job is not going smoothly.

[compactfean]

Id you have smog checks you will have to keep your air injection. If not you can cap off the exhaust and remove the system. You will not gain any horsepower from removing it.

[cmikk]

im in the same boat, man. my down pipe was so messed up i had to cut that pipe to get my motor out, and apparently nobody wants to admit this thing exists. i'm wondering which emissions tests will pass if i just delete it? the 2 or 3 articles i've actually found about it say that it was never really efficient, and they got rid of it for s14s, but that s13s will run rich on idle.

i presume that will affect emissions, but if the test is an acceleration test, then idle emissions won't matter, right? i don't want to buy a new down pipe if i can just plug the hole. i'm poor enough all ready. =]

[compactfean]

If they do a visual your are f***. My best recommendation is to get an air injection system from a 2000 or newer gm vehicle (s10 blazer our pickups are the easiest) and plumb that to a three way cat (magna flow off ebay is cheapest) and run the air injection line to the tube on the three way cat. This way since you are using oem parts it will appear stock but also work 1000 better than the stock air injection and then you could just cap the hole In the down pipe. Best stuff to use to break loose that bung is rust away, or jb80.

[cmikk]

thanks for the response. i'm in northern virginia, and i don't think they do a visual inspection. from their site it just says "two-speed idle test, acceleration simulation mode test and an on-board diagnostic system test". is there a writeup or something to install an air injection setup?

also, let me clarify what you're saying; the new air injection system will pump air into the exhaust before the cat to oxidize the exhaust gasses, right? so you grab the system, install it somehow, then it just pumps air into the cat the whole time, or just after startup? is it just an air pump into the cat, or is it more complicated than that? i would have thought that would be controlled by the ecu on the s10, but i don't know much about emissions systems..

[compactfean]

It depends on the vehicle on how long the pump stays on. some turn off after warmed up, some turn off after a certain rpm and some stay on all the time. (vehicles with mechanical air pumps stay on all the time matter what) the air injection system on the s13 is dated to say the least. It depends on exhaust pulses to suck in air into the exhaust before the cat. If you have a cat going out and start to clog the exhaust pulses that would normally draw in air simply stops working. Since 89 emissions have come a long way with three way cats (vs oxygenating cats where you used to have to replace the beads in the cat) electric smog pumps, and ecu controlled egr systems. If they are doing a ” 2 speed idle test” than you will be tested for idle emissions. yes the smog pump, pumps air into the exhaust injecting oxygen to help complete the burning process (lowers co levels which is the most common failure I've seen with 240sx) on the 240 the reason the tube is in the exhaust instead of the cat id because they simply didn't know that it worked better at the cat. I would wire it to run when the fuel pump is on. It is as simple as it sounds. The only thing extra is that there should be a check valve on the gm system, make sure it flows only toward the exhaust.

[Duce40sx]

You'll need to keep the air pump system as well as the EGR tube that runs on the back of the engine. Most likely 95% of aftermarket headers do not line up with this egr tube. Chances are most people delete it and fail smog. The EGR tube that runs from the EGR diaphragm to the header is needed in order for the system to work properly.

If you're in California like I am, there isn't a carb legal header yet or not that I know of, maybe one 1 out there if any. You should just clean your Idle Air Control Valve which is located on the back of the intake manifold, wire brush out all the tubings, replace any vacuum hoses.

Most likely aftermarket headers don't have the holes or fit the stock egr tubes.

Running a 93' DOHC ecu is the best because CEL on EGR system doesn't go on as regular as 91-92. There 93' has one less component as my friend had indicated to me which I forget now....

[compactfean]

Who is to say he can't upgrade the air system? Not everyone lives in cali. Here in nv you can put in superchargers turbos etc, as long as the emission components appear functional and it passes tail pipe. There are other options. N
California has the strictest rules.