I will update this thread with pictures and more information later.

A couple buddies of mine, and myself, took the July 4th weekend to our advantage and installed a couple goodies to my car, huge mistake in this record heat wave for Michigan. We installed COBB's 3" downpipe (without an O2 housing, just re-using stock) with O2/wideband bung already welded, and installed the AEM UEGO wideband AFR guage. It is a B!*#H getting that downpipe off and the new one on. I will explain further later. A couple long socket wrench extenders and this universal socket will save your life on this install, I promise:



What I do want to share right now is that after the downpipe was installed, I didn't throw any CEL's, which was a big relief. BUT the next day (this morning) on my way into work, the Check Engine Light came on. Now I'm concerned. I will update this thread later tonight when I find out what codes were thrown. Has anyone else thrown a CEL with just a 3" downpipe installed?

UPDATE (7/7/2010): Okay, I got the code checked. It's the wiring on the first O2 sensor - before the cat. We re-wired my narrowband gauge, which taps into the signal wire on the O2 sensor. We are going to check our wiring job this weekend. So, false alarm, the CEL is our mistake.

UPDATE (7/12/2010): VR4_EVO_IV and I took another look at my car this past weekend. We checked our wiring under the car, and everything seemed okay. We didn't check the wiring under my dash, though. So, to make things easier, I just said screw it, and we ended up disconnecting the narrowband gauge. I planned on taking it out anyway, replacing it with a trans. temp gauge, or oil temp/pressure gauge. I just disconnected the signal wire from the O2 sensor to the narrowband gauge. I drove it last night and this morning and the CEL didn't come up. If it does come up, I'll clear it and see if it comes back.
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I'll try to upload some pics to this thread at a later time. Here is my commentary, for the time-being.

For those installing upgraded O2 housing and downpipe parts, there are a few threads on the Evo X and RA sections that will help out. If you have JUST the downpipe to install (for instance, the COBB DP I used), the install may be a little more difficult, depending on how you look at it. Originally, "VR4_EVO_IV" and I were attacking this from the engine bay. When, honestly, it's MUCH easier to go from under the car when taking out/putting on the downpipe. This would work easier if we had a lift, but we didn't. A nice jack that lifts the car up more than 9 inches is desirable. Also, if you have more than two jackstands, that would help, too. Keep the hood open, lumination is a good tool (LOL).

Once the front end of the car was jacked up, and jackstands in place, we disconnected the cat from the downpipe, which is where an extra jackstand comes to play; rest the exhaust system on a jack stand. (By the way, there aren't good spots to put your jack stands on this car, WTF! If someone can chime in with a diagram of proper positions for jack stands, please let us know).

We didn't take the stock O2 sensor off, we left it on the stock downpipe. We bought an O2 socket from Harbor Freight earlier, which we used to unscrew the O2 sensor off the downpipe and back on for the COBB's dp. We pulled the carpeting up inside the cabin on the passenger floor, and just disconnected the O2 sensor harness. Be careful, the interior plastic pieces are fragile and weak (I broke some plastic mounting clips, and I'm not happy about it). You can then just feed the rest of the wiring through the hole in the passenger floor once the harness is disconnected.

Using appropiately lengthened extensions, a universal-hinged socket, and the correct size socket, un-do the passenger side bolt connecting the downpipe to the O2 housing. You may need a long-handle socket wrench or a breaker bar of some sort to break it loose. Once that bolt is off, move the downpipe downward as much as you can, and shove it over to the driver's side as far as you can, too. You just gave yourself a couple inches of space to work with. Now you'll have to get clever on how you'll approach that last bolt, because that's the hardest part of this entire install.

Once you're ready to install the new downpipe, repeating these steps backwards will help you: tighten the driver's side bolt first, then the passenger side. I'm not good at write-up's, so I apologize. If you search hard enough, you can pick up a few tricks from other members' threads of their experience in installing a downpipe. I made this thread for others, because there isn't enough info on the subject, I believe.

 

^ Interesting you getting the codes checked after work?


Anyways this is the OEM downpipe vs COBB (on the right lol )

 

Doesn't seem like it would be a huge difference in flow? Quality is better of course, but as far as exhaust flow goes they seem like they would be pretty similar.

-Taranis

 

No way, the cobb dp looks much wider, even with all the heat shielding on the oem piece of poo.

 

Stock is 2.5 COBB is 3"

He wanted to install it for future assurance of a cat back exhaust and so he can use the AEM wideband.

 

Just to reiterate the above, the stock piece looks absolutely tiny next to the cobb piece. Especially in the bendy sections.

edit: Also, I did not get any CELs from the downpipe. I did get on the 2nd time it was installed (long story), but that was because the O2 sensor had been damaged mysteriously in the process of the long story.

 

^ The wiring was taped for a narrow band AF gauge and we changed the wiring up alittle im thinking the wiring may have come loose during the install.

 

Pretty funny, because this may be along the lines of our issue. We are going to double check our wiring we did on my narrowband gauge.

 

 

Hey Tore, do you already have a tp or are you just going to run the dp?

 

I don't have a TP. Just this DP... I'm running stock cat, and stock exhaust. I updated the first post, btw.

 

You'll have to take me for a ride tonight. I'd like to see how the car feels/sounds now.

lol @ my first post.

 

^ LOL lurker