Car is in sig. 97Z28 A4. Im in Az and am supposed to keep my dual cat setup but heard I will get better results with the LT's. If I do go to the LT's, how do I get away from the front O2's that go in right before the cats that I have now? I was thinking of LT's and ORY with a single 3" cat. Not concerned with the smog jerks cause I can put the old ones on when needed. Thanks for any help.

 

Apparently its illegal to even move the cats from their stock location. Im not sure what you mean about the front O2 sensors. The front sensors need to remain on the car since they are what the computer uses to measure the air/fuel ratio. Maybe you are referring to the rear O2 sensors which only measure the efficiency of the cats... you can remove those but need to buy O2 sims or get the computer reprogrammed to ignore them.

 

I was looking into Pacesetter LT's and notice the rear O2 bungoles but didnt notice a spot for the front ones. How do I install LTs without those? And will Mids on my car give me the same performance? If its close enough I'll get Mids and not even dick around with the smog crap. Thanks for the rply also.

 

If you get a good shorty header like the single cat version of SLP or any other 1 3/4" primary header then the power gains will be very close. A member of this board made 420 rwhp with AI heads and cc306 sized custom cam through SLP shorty headers on a stock 350 bottom end... doesnt sound like much of a restriction if you ask me.

The front O2 sensor bungs should be welded on the inside of the collectors. You want them infront of the gaskets incase there are any leaks that may throw off the readings.

 

Those o2 bungs on the Pacesetter LTs are actually for the front 02 sensors. The rear O2 sensors are what you are on your own on. You will either need to do the following:
A. Use O2 simulators
B. Have the Rear O2 codes removed from the PCM via tuning
The power difference isn't that great between mids and LTs, if I were to do it over I would have went with the mids and eliminated alot of headaches related to passing emissions.

 

Yeah I saw the welded bungs on the LTs are right in front of the collector. Guess I would need one hell of a O2 wire extension for that. Guess I'll just look for a good pair of mids.

 

Excellent. Thats what I wanted to hear. Thanks guys.

 

Hey 2000GTP. I have 2.73's in my car now and was looking into new gears also. You happy with the 3.23's? I was checking into those and the 3.42's.

 

They came stock on the car, I am actually planning on upgrading to either 3.42s or 3.73s once I upgrade the rearend in the future.

 

Just a note, pacesetter makes a different set of LTs for 96-97 that do have the o2's.

 

They have a spot for the front and rear O2'? Thats would be great. But I wonder how much crap I would have to go through with the smoh crap.

 

The Pacesetter Lts will not have rear O2 bungs simply because it uses an off-road y-pipe which does not incorporate catalytic converters. You can't have rear 02 sensors monitoring catalysts that aren't even there. That is where the 02 sims. or PCM tuning comes into play. As you already know, your local emissions regulations will play a big part in what route you decide.

 

A pair of 12" O2 harness extensions is all you would need, not a big deal. Also, the Pacesetter do come with wiring and crimps so you can extend the harnesses yourself, but this can have its consequences.

 

Question: why isn't there an option C?

C. Drill sensor bungs in your Y-pipe and connect the rear sensors.

Just curious.

 

I was thinking about that, but then you would need some cats. in there as well. I am running mini-cats in my Pacesetter off-road pipe and I really wonder how efficient they are. I could take the chance and weld in bungs and put in the rear 02s, but then I'm afraid I will get an SES light and be back at square 1. Therefore, I have the cats. on there for a visual inspection and 02 sims. on there to keep the PCM happy.