Exhaust?
11-29-2009, 10:45 PM
#1
Former Sponsor
Thread Starter
Join Date: Feb 2009
Posts: 1,575
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
Exhaust?
Okay, I need a Cat put back on my exhaust. I have lost so much lowend it is crazy. I got around to putting the o2 back in and a thrush turbo with a turndown. It sounds like a V-8 but I lost a ton of lowend that I once had. I know I need it on there for back pressure and so on. Plus It is the right thing to do for emissions. Should I snag one from a XJ in a Junk yard? How far to space it from the muffler? How far for the o2 behind the cat? Just a general layout of where I should put everything back to get the best performance basically.
Oh and for reference here is how it is right now.
Oh and for reference here is how it is right now.
11-30-2009, 12:33 AM
#2
Senior Member
Join Date: Jun 2009
Location: Central Pennsylvania
Posts: 670
Received 0 Likes
on
0 Posts
Year: 1989
Model: Cherokee (XJ)
Engine: 4.7 H.O.
my 02 sensor is in the cat, connects to the exhaust just after the cross member (2 inches or so), best bet it grab a good one and put it back where it was stock, your exhaust should still sound as good as it does not. I'm just speculating, but I would guess your loosing low end because the o2 sensor is supposed to be reading the after cat mixture and mixing the fuel/air accordingly, without the cat it isn't reading right.
11-30-2009, 06:34 AM
#3
Seasoned Member
Join Date: Dec 2008
Posts: 495
Likes: 0
Received 2 Likes
on
2 Posts
Year: 1995
Model: Cherokee
Engine: 4.0L High Output
Yeah, you really need that downstream o2 sensor, probably more responsible for your power loss than the missing cat. I would check out the junkyard for that cat, and try to snag one off of the newest XJ you can. that or you could hit up summit racing for a Magnaflow direct replacement high flow cat. That's what I did and it worked out great, good quality part.
11-30-2009, 04:58 PM
#5
Former Sponsor
Thread Starter
Join Date: Feb 2009
Posts: 1,575
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
Went to the junk yard but the guy accused me of stealing parts! WTF! Last time I was there I pulled an o2 sensor, I thought the plug looked funny so I took it to my XJ and crawled under. Sure enough it was the wrong plug, The sensor was a Universal that you wire in. So I took it in to the guy and layed it down and said well the sensor wont work so heres a part thats already pulled for ya. I ended up buying a new one for about 85.00. I go back today and he says that is the wrong sensor that I stole the one that was supposed to be in it. I was so pizzed about this. I was like why would I steal one? I just spent 85 damn dollars for a new one. I hope this all comes back to him. Old Buzzard
12-02-2009, 07:01 PM
#6
Former Sponsor
Thread Starter
Join Date: Feb 2009
Posts: 1,575
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
Okay, went to a friends junkyard today to get an alternator and the older models wont work on a 97+. But anyhow the guy is going to just unbolt me an exhaust from a 97+ so I can just bolt it right back on my 99XJ. This way its all properly where it goes for the cat,o2, and the muffler. I miss the low end torque that my XJ use to have!
I hope this restores the power like I think it will,.
I hope this restores the power like I think it will,.
Trending Topics
12-02-2009, 07:12 PM
#8
Senior Member
Join Date: Jun 2009
Location: Guilderland NY
Posts: 842
Likes: 0
Received 2 Likes
on
1 Post
Year: 2001
Model: Cherokee
Engine: 4.0L I6 w/ K&N and bored TB
I have a thrush turbo on my Jeep with a turndown right after, and I have to say other than sounding better it made no difference in power, I dont know why yours is so much different other than I still have a cat.
12-02-2009, 07:34 PM
#9
Former Sponsor
Thread Starter
Join Date: Feb 2009
Posts: 1,575
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
When you lose a Cat you lose most of your backpressure which the 4.0 needs. I gained top end power but lost all bottom it seems. I had a ton of power before I messed with my exhaust. I love the v8 sound it has now but it lost alot of power.
12-02-2009, 07:36 PM
#10
Former Sponsor
Thread Starter
Join Date: Feb 2009
Posts: 1,575
Likes: 0
Received 0 Likes
on
0 Posts
Model: Cherokee
I need to get some more pics. I cut my front fenders and used the stock flares back on it. It turned out pretty darn good. Just need to paint some more and I will get some new pics up. Now I just need that tubing front bumper on there
12-02-2009, 08:02 PM
#13
Newbie
Join Date: Nov 2009
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1989
Model: Cherokee
Engine: 4.0
Ouch...I bit my tongue too hard 
I'd love to hear what the Jeep engineers have to say. Still might not believe them but would be interesting just the same.
I'd love to hear what the Jeep engineers have to say. Still might not believe them but would be interesting just the same.
12-03-2009, 05:58 AM
#15
Seasoned Member
Join Date: Dec 2008
Posts: 495
Likes: 0
Received 2 Likes
on
2 Posts
Year: 1995
Model: Cherokee
Engine: 4.0L High Output
I had the no cat to thrush turbo to trundown setup on my XJ for a bit and I can't say I noticed a huge difference in power.. I will say that I hated the sound though, way too hollow and loud, it made the truck feel slower cause it sounded like crap. I only ran that setup long enough to get my Magnaflow aftermarket cat from summitracing.com and my catback from 4WD.com. Sounded so much better and I actually believe it made power having a FULL exhaust on the truck 2.5" all the way. I will say that the best power upgrade I have made thus far has been the ATP header, that really gave my exhaust a throatier note with a nice low idle note as well as a nice kick in the *** at full throttle.