Killing the Cat

[TripleJackInGA]

Anyone had a chance to crawl under and around the thing to see how many O2 sensors it has?
I know people who have developed things to make the computer think the one after the cat is reading normal so you can remove it (resistor).
What do you guys think about yanking the Cat.? I know turbo engines as a general rule do need some backpressure in the exhaust, so would this be worthwile?

[Dalite]

It has 2 sensors; one upstream (near the turbo outlet) and the downstream one installed in the middle of the CAT. Both are wideband O2 sensors and are heated.

Taking the CAT off would most likely throw an error code perpetually. Perhaps the easiest way would be to weld a bung on the replacement for the cat and reinstall the sensor there.

[PT GT]

There are some companies that make a fake o2 sensor. It is set up to make the computer think all is ok at the second location. So you only need to hook up 1 o2 sensor to the straight pipe. Not sure if it is being made for the PT GT but worth checking into to.

[Dalite]

I was thinking that may also be an option. All it would have to be is a voltage regulator that would take the 12 volts that feeds the heater and outputs 3.0 volts. The PCM should see 3.0 Volts as a perfect mixture. I don't know what kind of error trapping the PCM will do if it sees non-varying data from the CAT O2 Sensor.

FWIW, a LM317 Adjustable voltage regulator has a range of 1.2 to 32 volts. Output current capability is 100 mA, which should be plenty. With 12 volts in and the proper resistor divider network, it should give a range of 1.2 to 10 Volts within a .15% regulation tolerance.

The problem with all this theory is that the service manual and diagnostic manuals don't give much info about the individual sensor inputs, and it would take someone willing to experiment to see if this all works. With the stock PCMs being on backorder status, it is a gamble to see if this would actually work.

[Exhaust Depot]

I am working on something for you guys so dont worry about it.

Oh dalite,

I placed an DVM on my car and ran it. It would go from 2.5 up to 3.5 Max. At WOT i would get 3.49 V on it.

Just some gee wiz info.

[dsm_mike]

Get rid of it! Combined with an upgraded exhaust, you will see definite gains. Maybe up to 30 hp or more, thats about what I got on my talon. BTW, that 30 hp for both,not just for the cat. Ive been waiting for someone who doesnt have to worry about emmisions to rip the cat out to see what kind of gains we can get from it. Oh, and you have it backwards, turbo engines do NOT need backpressure. The less backpressure, the faster it will spool.

[Dalite]

Hector,

digital voltmeter display boards can be purchased from many of the electronic kit makers. All anyone would need is a voltmeter that could be mounted in a small enclosure and placed in a location that is visisble from the driver's seat. The only problem with a digital gauge is that it is harder to read than an analog with a needle and 207 degree sweep.

The 2.5 to 3.5 volts with 3.49 at WOT confirms that the signal is the 1.0V range that is industry standard; only bumped up by the 2.5 volt offset.

That Gee Whiz stuff is what keeps us byteheads (me) going.

[03baggedturbo]

on my saturn I had a straight through pipe.. we drilled a hole and welded in a bolt the same size at the o2 sensor.. the 02 would screwed in the bolt.. on my saturn it didnt throw any check engine lights.. not sure what it would do on this car though..? I made the test pipe so I could take it on and off.. but it was more time consuming than I thought to actualy take it on and off.. since the bolts were hard to get to and the bolts would kinda rust and were hard to loosen..

[mich_132003]

I have also heard of, not on PT's, the CATS can be gutted out so in PA you can pass visual inspection but I also understand this can be detected by the computer. [:I]

They also have HIGH FLOW Cats on the market. Jegs has them in their catalogue. Don't know that much about the HIGH FLOWS other then they work well from other non-PT forums. Increase in HP without sensor problems. [:I]

[TripleJackInGA]

Even though the Metro Atlanta area has changed from 13 to 28 counties recently, I still live far enough away that I don't have emmisions inspections.

Gee Whiz.