all muffler and exhaust questions go here!!!!!!
Junior Member
Joined: Feb 2012
Posts: 91
Likes: 0
From: perrysburg oh
Year: 1996
Model: Cherokee
Engine: 4.0L HO
my manifold is cracked and its just been annoyingly loud till now. did tune up a month or two ago. runs better but now i have a horrible hot start problem. have to floor it till it starts then she runs like
for a couple min then shes fine. if i dont shut her off no problems. not sure if it's fuel related or build up or wth it is. any help appreciated.
for a couple min then shes fine. if i dont shut her off no problems. not sure if it's fuel related or build up or wth it is. any help appreciated.
Senior Member
Joined: Apr 2010
Posts: 649
Likes: 4
From: Houston, Tx
Year: 1999
Model: Cherokee
Engine: 4.0L
Didn't feel like reading through the 101 pages of questions, so this may have been asked already before, but, how hot is too hot for the exhaust? I'm running round between 400-500F at the header / block interface, the runnin in the low 400's down the headers, 400-500F at the expansion bulb when it runs across the tranny, high 200's on the cat (as i just replaced it because it was hittin the low 400's), muffler is around mid 300's, and the tail pipe is on the higher end of the 300 range.
one thing i noticed, all the rusted pipe was where the higher tempereatures were, do i just need to replace everything, or is 500F normal? (it's not glowing yet, lol)
one thing i noticed, all the rusted pipe was where the higher tempereatures were, do i just need to replace everything, or is 500F normal? (it's not glowing yet, lol)
Senior Member
Joined: Apr 2010
Posts: 649
Likes: 4
From: Houston, Tx
Year: 1999
Model: Cherokee
Engine: 4.0L
Senior Member
Joined: Sep 2010
Posts: 905
Likes: 1
From: Llewellyn, PA
Year: 1998
Model: Cherokee
Engine: 4.0L I6
My Cat converter is rattling, something is obviously loose on the inside. Because this is my first vehicle and I have never had to get any exhaust component replaced, I need to know if I can replace the cat myself (which I THINK is actually illegal to do) or if I need to get it replaced at a shop? Do I need to go to a certain shop, or will any shop that does mufflers/exhaust be able to replace it?
Senior Member
Joined: Apr 2010
Posts: 649
Likes: 4
From: Houston, Tx
Year: 1999
Model: Cherokee
Engine: 4.0L
My Cat converter is rattling, something is obviously loose on the inside. Because this is my first vehicle and I have never had to get any exhaust component replaced, I need to know if I can replace the cat myself (which I THINK is actually illegal to do) or if I need to get it replaced at a shop? Do I need to go to a certain shop, or will any shop that does mufflers/exhaust be able to replace it?
Senior Member
Joined: Apr 2010
Posts: 649
Likes: 4
From: Houston, Tx
Year: 1999
Model: Cherokee
Engine: 4.0L
ok so i have a flowmaster 40, real nice sounding, i have some friends who have comepletely did away with there cats. just straight pipe into the muffler and it sounds great. so i wanted to do this mod, but not have to search for a shop to inspect my jeep and look over the removed cat. so i chose to just cut the cat off, and gut it. gutted it, welded it back in, sounds amazing for a 6cyl. the I6 sounds way better then most V6's. but my question is, i was told with gutting my cat, id get more back pressure, which could eventually burn up my valves. how true is this
CF Veteran
Joined: Nov 2011
Posts: 2,433
Likes: 6
From: Northern MN
Year: 1990
Model: Cherokee (XJ)
Engine: Renix 4.0
ok so i have a flowmaster 40, real nice sounding, i have some friends who have comepletely did away with there cats. just straight pipe into the muffler and it sounds great. so i wanted to do this mod, but not have to search for a shop to inspect my jeep and look over the removed cat. so i chose to just cut the cat off, and gut it. gutted it, welded it back in, sounds amazing for a 6cyl. the I6 sounds way better then most V6's. but my question is, i was told with gutting my cat, id get more back pressure, which could eventually burn up my valves. how true is this
I like it for the few years I drove around like that with a GP.
haha ooopppps. my fault. wasnt aware that you couldnt talk about frowned upon modifications. haha but preciate the reply. im just a young and dumb kid. soo ill just keep rocking the guttless system. sounds good and got a nice increase in power
CF Veteran
Joined: Nov 2011
Posts: 2,433
Likes: 6
From: Northern MN
Year: 1990
Model: Cherokee (XJ)
Engine: Renix 4.0
Last edited by austinjoe13; May 13, 2012 at 09:41 PM.


