Killing your cat

[TripleJackInGA]

OK, so I was looking at what 3Bar said on another thread, which was:

"Actually, a CEL will come on if you delete the cat on any of the Stage kits (remember what I keep saying about passing the sniffer?). All the Stage kits run just fine with it in there, and cats don't degrade if you push more air through them. So doodling around town, the cat works just fine and keeps the tailpipe squeaky clean. Up top, the fuel goes open-loop anyhow and catalyst efficiency drops whether or not you have a Stage kit. Fortunately emissions isn't regulated up there - not that any car could stay squeaky clean at peak power, turbo or not.
If you were serious about power, and cared not about emissions compliance - a 2.25" straight through (race pipe) is more than fine with the stock turbo. However, a bigger turbo will want something bigger - the Stage 3 doesn't make any more power on the SRT with a 3". A PT installation might be different (because of the extra bends), but I think most 2.5" systems are fine. The O2 housing (what I call the downpipe) is not really that restrictive - it's something you'll change if you are after every last BHP, but your money is better spent upgrading to the Stage 3 turbo housing."

I live in an area in which there is no emmisions testing done....for now.I am interested in removing the cat, but it appears from 3Bar's post that if you gut or remove the Cat to install a racepipe, your CEL will come on. I assume this is not detrimental to the car, it's just saying 'Hey, this s**t ain't working right!'.
Is there any way to use a series of resistors on the O2 plug to trick the PCM into seeing the voltages it wants to see to be happy from that O2 sensor, with it being a heated O2?

Anyone here gutted/removed their Cat and not had a CEL/MIL come on, or a code set?

[Dragula]

Chevy's with LT1/LT4 engines that are OBDII (mine is not thankfully) use O2 sensor simulators to fool the PCM, but I doubt if those are applicable to this car. I'm guessing that it's possible, and some vendor is probably working on that if it's not available already. I'd look on the SRT forums for info on that as well.

[98 Neon Driver]

You can fool the PCM w/a resistor, the neon guys have been doinf it for quite some time. However you won't see any gains from removing the the cat, you might squeak out 1 or 2 more horse. Not worth it IMHO.

AC

[TripleJackInGA]

I know about the sims, we did them with the Dakotas, but I thought you couldn't do it with the newer heated O2 sensor that these use.

[Mean Green]

quote:Originally posted by MEXICANPT

I installed today my ATP 3" downpipe with cat, and let me tell you I'm not even thinking about deleting the cat at this moment.

The car above 4000 RPM feels like a completely different car, I ran a 3" tube from the dp all the way to the axle where it connects with a BTG axle-back.

It sounds just like an SRT-4 and it pulls like crazy now, very happy with my newest mod.

You went from 3" pipe to 2 1/4" pipe on the BTG?

[Cal Cruzer]

How hard was it to get the old pipe out and the new one in. I was noticing when I installed my catback that is looks like a really tight area up in there.

[MEXICANPT]

I really couldn't say how hard it was to install it, since I didn't do it myself, I don't think it was that hard.

I stuck with the BTG axle-back because my car is lowered and when I have people in the back seat the exhaust touches the rear suspension on every bump, I did it for clearance issues.

But make no mistake about it, it really feels much better, and it's definitely faster.