Hey guys-

Well, I just ordered a Apexi WS catback. Woo hoo. Now I have a few questions.

First - is this cat back all Stainless Steel, or just the muffler? It doesn't really make a difference, just wondering.

Second, I talked to theblue a little yesterday (he has this catback) and he said that there is no hole for the rear O2 sensor. He said that you could either get a hold drilled to install it, or just hang it and live with the check engine light.

As of right now m rear O2 sensor appears to be shot, and my check engine light has been on ever since I installed my RT cat (codes 0707 and 0902). I am not worried about the rear O2 sensor for montioring the cat, I know that it is in good shape.

My concern is that if I just hang this O2 sensor outside of the exhaust, and one of my front O2 sensors goes bad, what would the ECU do? Could this be potentially dangerous?

Thanks!

 

You should drill the hole and replace the o2 sensor, if your o2 sensor is not working or hooked up it will screw up your emissions and MPG. It is easy to drill the hole and weld a bolt in place. Any custom muff shop should be able to do this.
Sensors not working usually are not dangerous, just not great for your car and the enviornment.
A custom muff shop may be able to improve the fit also, it is actually designed for a 95-96, which has the o2 sensor on the cat, and no lip on the rear bumper. On your 97 it will sit recessed about a inch or two....

 

Really? Its my understanding that the rear O2 sensor doesn't really do anything unless one of the front two fails.

As far as being recessed, theblue has a 97 with it, and I really like the way it looks, so I'm not worried about that.

Thanks for the info.

 

nice choice. what are u going to do with ur bpipe and muffler now? i thought u just ordered ur b pipe!?

 

Well, I kinda ordered the b-pipe. Courtesy is backorderd until the middle of August, so I already cancled that.

The muffler will go for sale after I get it off the car and get some pictures taken.

After following Aaron to the track recently, I decided that I like the look of his a lot better, and at the price I found, I just couldn't pass it up.

 

was it a gd? cos now i am reconsidering too! its just a maybe though, i want to get the y before i do anything else. how much did u pay for it?

 

Nope, "wrecked" was selling it in the forsale forum. He was selling it for a little less, because he lost the hardware for the kit (bolts and gaskets, but I can take care of those). Brand new though! He's a nice guy, I guess he's a dealer for Apexi, and can give a discount on new ones. You might wanna get in touch with him if you're interested.

I paid $275 shipped. I was going to pay $200 for the bpipe, but now I can sell my muffler and it should end up costing me about the same for the catback!

This means that next weekend I am installing the UDP and catback...and I have stock wheels sitting at my place now. Next time we go to the track I should be doing much better!

 

nice nice. i know how excited u must be right now. we gotto see how much better u do at the track next week! 14.6 maybe

 

As long as I keep beating Aaron

 

Back to the orignal question, anyone else have any input for me?

 

This is not completely correct.

The Engine Control Module does not use the rear Oxygen Sensor signal for controlling the fuel mixture unless one of the two front Oxygen Sensors has failed. When both front sensors are working normally the rear sensor works full-time evaluating the condition of the Three Way Catalytic Converter.

 

Daniel -

Thanks for the input. I understand this, but my aftermarket "highflow" cat causes the ECU to throw codes 0707 and 0902. I've re-installed the stock cat and they go away, leading me to believe that its just the RT cat that I have on there. I belive it to be working fine though. Other members have had this problem, and say it has something to do with the position of the converting element in the RT cat VS. the stock cat.

Either way, I am not worried about the rear O2 sensor monitoring the cat, just incase of the failure of one of the front two.

So, what would happen if I did not have my rear O2 sensor installed, and one of the front ones failed? Is it something that I should really worry about?

 

I don't know. It seems like a worst-case scenario, where the Engine Control Module tries to switch to its emergency backup and the backup isn't there.

 

Who knows? Well, I think I'll hunt down a exhaust shop to drill the hole in the new b-pipe so I can have the sensor in there for piece of mind.

Thanks!

 

The rear o2 is not used for adjusting air fuel mixture. Even if both front o2 fails, the computer will not look at the rear one for help. Since your mil is already on because of your cat, don't waste your money drilling a hole.