Exhaust, O2, and running open y-pipe (Magnus, this is for you)

[strobhen]

Have a dilemma here, as some of you may know, I plan on putting a cutout before the cat for use at the track.

Now, I am pretty certain there is an O2 sensor after the cat, have also been told that there are 2 others, one on each header.

Now, I would be bypassing that 3rd one, so are there any problems with doing that? Do I need O2 sims, etc. I don't think Magnus uses sims, since he seems to rely on O2 readings to tune his car, so what's up?

Later & thanks for the help.

[Magnus]

There is an O2 in each primary (header)... These are the O2's the car uses to determine the air/fuel ratio. The one on your car after the cat is ONLY there to check the effeciency of the cat. It will set an SES light if your cat is not functioning propery.

Good luck fitting a cutout before the cat, there is very little room, My guess is it will have to go right after the cat.

I do have an o2 simm on my o2 that goes right after the cat. Doesn't affect the performance at all.

[96 T-Top Bird]

I also thought of putting a cutout before the cat, doesnt look good. Not much room at all.

But if you DO fit it somehow, u will most likely get an SES light. Not really a big deal, if u have an autotapper u can just clear the code. Nothing will happen.

I've had mine go off many times on the highway due to the cat. I just cleared the code and back to normal.

[strobhen]

I plan on getting RKSport headers -- which have a crappy y-pipe design.

So what I will do is have the shop make me a new y-pipe/cutout combo ;)

I don't see much of a problem with that approach, you don't need much space for a hole.

[ February 22, 2002: Message edited by: strobhen ]</p>