Exhaust systms - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > Exhaust systms

Rough Country Jeep Suspension Deals at Rockridge 4WD!Looking to re-gear?! CRAZY DEALS ON YUKON GEARS right hereJK specific skid plates from Clayton Off Road Mfg.

Closed Thread
Unread 01-31-2012, 10:33 PM   #1
lvngtheJEEPlife
Registered User
2001 WJ 
 
Join Date: Aug 2011
Location: Plainfield, Illinois
Posts: 929
Exhaust systms

I have a 94 ZJ with the 4.0, i strapped on a magna flow muffler on a eliminated the Cat, but i left the stock pipes. Will this hurt my performance? The stock pipes are really small, so is the new muffler doing nothing because of too small of pipes? thanks!

lvngtheJEEPlife is offline  
Unread 01-31-2012, 10:48 PM   #2
stormer1092
Registered User
1994 ZJ 
 
Join Date: May 2010
Location: Marquette, Michigan
Posts: 538
I'm no performance pro but a more flowing pipe is more than likely helping same with eliminating the cat and replacing it with a test pipe. I heard somewhere someone correct me if i'm wrong but a 2-3/4 pipe is the best size for the 4.0. I believe stock is 2-1/4.
__________________
Quote - I currently have this set up with some ok shocks. Mine rides stiff but its not completely unbearable. My rear end is what kills me more than anything. Signed - Okie_Rider
stormer1092 is offline  
Unread 01-31-2012, 10:59 PM   #3
zander21510
Lord of Retro Machines
 
zander21510's Avatar
1995 ZJ 
 
Join Date: Jun 2011
Location: Dallas, TX
Posts: 1,754
...btw eliminating the cat is illegal by federal law...I see closure ahead!

Anyways, from what I've read you need a little bit of backpressure on the 4.0 to have it reach its full potential...but keep in mind it just wasn't meant to go fast lol. They make hi-flow cat's and mufflers.

PM Kolak, he's the man to talk to with exhaust.
__________________
1995 Jeep Grand Cherokee;
207,000 miles (2/6/14)

206k: 1/6/14;
205k: 12/21/13; 204k: 11/22/13; 203k: 10/8/13; 202k: 8/29/13; 201k: 7/15/13; 200k: 6/8/13; 199k: 5/10/13; 198k: 3/17/13; 197k: 2/22/13;
196k: 12/20/12; 195k: 10/26/12; 194k: 8/17/12; 193k: 5/29/12; 192k: 3/16/12; 191k: 2/18/12;
190k: 12/31/11

Current mods: 703 injectors(my howto), intake modification, 99+ intake manifold (my howto), Magnaflow hi-flow cat from Kolak & Cherry Bomb glasspack.
zander21510 is offline  
Unread 01-31-2012, 11:05 PM   #4
stormer1092
Registered User
1994 ZJ 
 
Join Date: May 2010
Location: Marquette, Michigan
Posts: 538
Quote:
Originally Posted by zander21510 View Post
...btw eliminating the cat is illegal by federal law...I see closure ahead!

Anyways, from what I've read you need a little bit of backpressure on the 4.0 to have it reach its full potential...but keep in mind it just wasn't meant to go fast lol. They make hi-flow cat's and mufflers.

PM Kolak, he's the man to talk to with exhaust.
hey now he installed a test pipe.
__________________
Quote - I currently have this set up with some ok shocks. Mine rides stiff but its not completely unbearable. My rear end is what kills me more than anything. Signed - Okie_Rider
stormer1092 is offline  
Unread 02-01-2012, 02:53 AM   #5
Buzz98zj
Registered User
1998 ZJ 
 
Join Date: May 2011
Location: Lyndonville, Vt
Posts: 644
Can't believe this wasn't shut down yet. Lol we don't discuss emissions here.
__________________
98 5.9
Buzz98zj is offline  
Unread 02-01-2012, 05:30 AM   #6
ratmonkey
R.I.P.
 
ratmonkey's Avatar
1997 ZJ 
 
Join Date: Dec 2006
Location: , Pennsylvania
Posts: 19,805
put a cat back on it. no performance gain from it being gone, it's illegal, it's bad for the planet.
__________________
'97 zj 5.2, some stuff, some other suff, and some things that even work sometimes.

ratmonkey is offline  
Closed Thread

Tags
exhaust , exhaust system , muffler replacement , performance improvements
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.