I have a '99 SE-L Cali spec, and I just got a Fed spec front header.

I plan on having an equal length Y-pipe made to ditch the Pontiac sound my 2.5" exhaust has, as well as free up some power. But I am confused as to how to proceed with the O2 sensors.

I found the thread where The Wizard talked about how to wire up a sim, but I couldn't follow it. Also, I don't know what sensors I have, or what to replace with sims. I will keep my stock back cat, just looking to ditch the front one(s).

So my question is, what do I need to get, and how do I hook it all up?

Thanks.

 

So because you're in cali, you have to run O2 sims for the fronts?

If you make an equal length one, just use your main cat to pass emissions. I wouldnt bother with O2 sims.

By the way, good for you on equal length.

 

No, I'm actually in NY.

Cali spec cars, from what I understand, have the regular cat, and a cat in the front header, as well as before and after O2 sensors on all of them.

I am ditching the front header for a Fed spec one to make the custom Y I want and get gains from it. However, I don't want an SES. Hence the need for O2 sims, as the first after sim is made to check the performance of the pre-cat.

 

I'd PM The Wizard

 

o2 sims are very hard to come by these days thanks to the epa's crackdown. Your better off getting some bungs welded in after your main cat and extending the wires.

fyi same amount of cat's as on a regular 4th gen, just different set-up for the front one, and the main cat doesn't have a post-cat o2 sensor. Do you have a resonator on your car? No resonator is the first thing that popped into my mind when you said that pontiac sound, just a thought............

 

Sounds is very subjective, but IMO, seems as if the unequal sound gives the Pontiac / dump truck sound.

I went from a very nice sounding smooth tone, and then to a Pontiac sound by changing my y-pipe ONLY.

 

A big to nmex--only good sounding maximas I have heard have been equipped with an equal length Y (I even made a thread about how ****ty VQ30s typically sound).

So the O2s will throw a code if the exhaust hasn't been treated by a cat beforehand? I was under the impression that they were there more for AFR reasons

Guess I need to read up a little more

 

Also: be sure to post up pics of the final product I am considering going the same route.

 

My exhaust sound was absolutely PERFECT when I first got it. However it seems like the resonator is starting to "break in", allowing higher frequencies to get in and make that trademark Pontiac sound...

I like the sound of extending the wires though. I will have to consult my Haynes manual to see what the readings on the sensors are.

Which is exactly why I want to go with equal length. The ****ty stock y-pipe makes for decent sound. If this turns out to be a success I think I will get the shop who makes it to make a batch of them.

 

Always eager to help.

What do you need help with specifically? What don't you understand about my wiring advice/diagrams in that old thread you're referring to?

I bought my O2 sim from Cattman.

For starters, you'll be simulating both downstream O2's. You know which ones are the downstream O2's, correct? You can't simulate the upstream O2's.

 

If they fit over an LTBII I might be interested...

 

what is the pontiac sound?

 

Ever heard an L36 or even an L67 w/ aftermarket mufflers?

 

This is pretty much exactly it.

http://www.youtube.com/watch?v=bwGkY1oeD8U&NR=1

 

I don't know/understand the O2 setup my car has, and consequently what I will be replacing.

There are 4 O2 sensors, correct? I know of one before the front cat, and one right before the back cat. Where are the other two, and what am I replacing???

 

ur car sounds like that? thats horrible man.. i have a cattman catback and obx shorty headers n ypipe and my car sounds nothign like that

 

Is that what my post says? Going to go ahead and assume that your reading abilities are on par with your typing skills....

 

nah my bad i was referring to the op.. guess it does seem like i was talkin to you

 

that honestly sounds pretty nice. it sounds better then alot of the raspy maximas i have heard before

 

Can someone link to The Wizard's O2 sim writeup?

 

Correct, you have 4 O2 sensors. Two on each bank. The easiest way to determine and learn about the O2 sensors is to check out the FSM. The FSM shows the location of all four of them. Or, you can pop your hood and look for them, and get under the car to see the hidden ones. After you locate all four, take note of which ones are upstream and downstream. You can only simulate the two downstream O2's.

You are not replacing anything. You are connecting the two dowstream O2's (which are dangling loose) to the simulator. I ziptied the dangling downstream O2's to the center support under the engine, then put some heavy duty double sticky tape on the back of the O2 simulator and stuck it to the the center support as well. I placed the simulator and O2 sensors out of harms way and in such a way that elements like water, rocks, debris can't get to them.

Some other food for thought. Since you're having a custom ypipe made, you could have the welder add some extra bungs for the O2's and you can avoid the hassle/headache of wiring in the O2 simulator.

 

I believe this is what Skuccio was referring to....

http://forums.maxima.org/showthread....3178&highlight

 

Yes but wouldn't I get an SES? I was thinking of doing that too.

 

Nope. You won't get any CEL's.

Just curious, why do you think you'd get a CEL with this approach????

 

I thought the downstream O2s were there to validate the effectiveness of the pre-cats. If there are no cats, they get the same readings as the fronts = SES light. But if not I will def. just do that.