Hi everyone. I wanted to ask if i install a catback system (nothing specific) any type will the check engine light come on? And if i take out all the catalyst and just put in one for ex magnaflow will it cone on to?

 

Removing the catalyst is a federal crime. Other than that, the answer is probably not.

 

Well here sice its hard to get catback systems for any jeep thats what we have to do to get a nice sound. iam asking because on my trailblazer i did that and the service engine came on. And do you think by taking out the catalyst i will gain power?

 

They usually always do. Anytime you make an exhaust mod and they get louder, you're reducing backpressure and that usually equates to more power. Usually, but not always. We used to drill like six or eight 1/2" holes through the catalyst media to improve flow. It worked, too. They would still pass a smog test. Keep in mind, when I say this, I am talking about probably 20 some years ago. Technology has changed somewhat and it might not pass now. I'm in no way encouraging you to do this, it's just some of the highjinks we used to do. You can still get jail time. LOL

 

Heheh thanks but here believe me i wouldnt go for jail for that, a cop might even commet on how nice it sounds. We have mustangs that have just headers on here and they shoot fire from under and nissan skyline from 1977-1984 that have nothing on and are soo loud you barely can stand close to the car. about the law is no problem, but its hard to get a catback system here and i love a loud roaring sound so i want to do anything just to have it.

 

OK, I just now noticed where you are.

 

Hehe yeah if i would have a Z71 or a yukon then no prob getting a exhaust system. But nowadays the laws are getting a bit tight like if you have decals on the car they take your car to the impound for a month, but the exhaust thing i don't thing is a problem.

 

There are actually 4 catalytic converters on the JK, split between 3 cylinders each. There is an O2 sensor between them. I'm quite certain you'll have unwanted lights if you (illegally) remove them.

Here's a thread on the topic:

https://www.jk-forum.com/forums/show...ight=catalytic

 

Thanks for the reply. But i can't figure out still how to make the jk sound loud and aggresive? i don't want to loose power to. anybody have suggestions?

 

This is all IMHO, so don't flame me if you think otherwise.

Unless you modify the engine you will gain very little, if any, power by using a "better" exhaust. If you do gain anything it will likely be at high RPM. Any aftermarket exhaust is likely to be louder. There are sound clips on this site. You will not find much real data on power increases. The increases may be statisticaly insignificant when measured on a dyno, and very few would pay for such services when they know they are only looking at the potential of a few hp at high RPM. Many will share their views on "butt dyno" tests. Also, I think that many here have done exhaust mods to get the stock muffler to a safer location, not necessarily for performance.

If you modify or remove the cats you will get a CEL. Catalyst efficiency monitoring will detect any significant cat problem. I have heard of hardware that can simulate the downstream O2 cat signal, but I know very little about it.

If you want big sound, try this. Cut off the stock muffler with a saw. Go for a drive. If it is loud enough, then buy the most minimal muffler you can find.