JK-Q8

Hi all, i wanted to take out the 4 small cats to increase flow and sound to my gison dual, and between them there is an o2 sensor and i know if i take them out the engine light will come on. How can i do it without having the light go on? how can i fool the sensors?

cyberbrain

I would recommend getting 4 high flow cats, that way you can stay legal. However if you go to the parts store and pick up spark plug anti foulers (its a HELP product) and drill the bottum out so the tip of the o2 fits in there, you will be fine. Yes they are the same thread.

cyberbrain

once my main forum is up I can post links for ya. Many of us turbo 4cyl guys used this trick when we did not run CATS with a turbo setup. It was a simple and cheap way to keep use legel *no SES* and no cat.

whpony96

They are usually about $50 and are called MIL Eliminators. (Malfunctioning Indicator Light) You can buy them at a mustang parts web site. I know BBK makes them. Not sure of they would be the identical plug for a jeep but this it what I used on the my Mustang to remove the "check engine light". Considering the JK has the CANbus system in it you would want to make sure that this would work. If it throws a check engine light prior to getting the MIL's installed or if the MIL's don't work due tot he CANbus system you will have to go to the dealership to reset the check engine light. Unless of course you have a Starscan tool handy!

I can tell you this when I removed my cats completely from my mustang (off-road h-pipe) I lost my low end torque all together. So I then put on 2 high low cats in a X-pipe (instead of 6 from the factory!) from Magnaflow and got it all back and the sound i wanted too.

Now with the JK's we need all the low end torque we can get our hands on. So we can't afford to give up any torque. So looks like a Dyno might need to be involved to see what the results are.

ChewyGranola

Thanks for making smog worse.

cyberbrain

the problem with a MIL eliminitor or totally removing the o2 is the ecu can't run the engine correctly as it doesn't know how much a/f it is running. So it could run really really rich, and now you have EVEN worse mileage. my suggestion of the anti fouler still lets the stock o2 control the engine. How my mod works is the o2 is looking for a specific amount of chemicals in the exhaust. If you remove the cats it ggets to much air and you trip the SES. However with the antifouler it removes the o2 from the main exhaust flow and lets it meter what it is looking for.

H2_RESQ

Get someone to custom tune the ECU to work w/out cats.

JK-Q8

Thanx for the help/ I got a bit scared of with all i have to do. There are 2 cats then the o2 sensore and then another 2 cats. If i take out the last to will there be a light on? And how can i gain back the low end torque without loosing the sound? since am doing all this for the sound. thanx in advance.

Bob Coco

Unless you do an awful lot of engine work the 3.8 V-6 will never produce a powerful sounding exhaust. Just install a quality cat back system. Keep it legal and warrantied that way. These JK's have a computer system that ties every system in your Jeep together. Plus as a few people have already mentioned you will lose some low end performance. There's no substitute for cubic inches. If you want it to sound like a V-8 then save your money up and buy a V-8.

RedneckJeep

No such beast as a high flow cat. Don't let people fill your head with crap. Cats have to have heat to operate. They get that heat from backpressure. People just automatically think that if something is in the exhaust flow, that it'll get hot. This is true to an extent, but it ain't gonna get the 600+ degrees it takes to operate a cat without backpressure. Backpressure is NOT an affect of "high flow", I don't care who says it. Don't waste money on high flow cats. If your engine is still stock, you'll likely see a power drop if you remove the cats. The engine is designed to produce the power it has with the backpressure of the stock exhaust figured in. If you don't change the exhaust as an ENTIRE unit, (Headers, and a good cat back), you're just pissin in the wind. You're likely pissin in the wind with what you have. Everything I've seen posted on this forum about the Gibson dual, says you lose power. People can argue about the "honeycomb" in cats is high flow all they want, but it just ain't so. Every car maker now uses the honeycomb cats, so they are already using that "high flow" technology everybody is talking about. I've stood there and seen the difference (not!) in a stock cat VS a so called "high flow" cat using a backpressure gauge. The "high flow" cat actually had more backpressure. We don't really know why, other than the fact that the "high flow" cat had more actual honeycomb "area" for the exhaust to have to travel through. I mean, damn, just look at this statement. High flow catalytic converter. How much more ironic does it get? Remember the old saying, "if something sounds too good to be true, it probably is."