dragonrider477 Posted March 11, 2008 Share Posted March 11, 2008 my mj came with a new exhaust system from the po.according to what i found out at the parts store,it's too small.the parts guy said it should be 2.25"from the back of the cat to the end of the tailpipe.mine is 2.25 at the muffler inlet.2.0 at the outlet and the tailpipe is 1.875.will this hurt performance? the truck seems a little weak when i step on it and wind it out to higher rpms(2500-3500).truck is 2wd,4.0,5 speed,3.07's removed and replaced with 3.55's. Link to comment Share on other sites More sharing options...
Oizarod115 Posted March 11, 2008 Share Posted March 11, 2008 pretty sure mine is 2.25 all the way back (stock or replacement stock stuff) and yes smaller pipes will constrict some but i can't tell you for sure how much. if you're looking for optimum everything from what i can tell 2.5" is the best size for some backpressure but freeflowing Link to comment Share on other sites More sharing options...
FxRacing282 Posted March 11, 2008 Share Posted March 11, 2008 its on the small side. but you get some great torque and better fuel economoy. Link to comment Share on other sites More sharing options...
dragonrider477 Posted March 11, 2008 Author Share Posted March 11, 2008 its on the small side. but you get some great torque and better fuel economoy.well,it does do 22-23 mpg on road trips.maybe i'll wait till it rots out before i mess with it,thanks. Link to comment Share on other sites More sharing options...
FxRacing282 Posted March 11, 2008 Share Posted March 11, 2008 yeah thats great. good thinking Link to comment Share on other sites More sharing options...
Eagle Posted March 11, 2008 Share Posted March 11, 2008 Sounds like someone put a 4-cylinder exhaust on your 6-cylinder truck. As commented above, unless you spend a lot of time at wide-open throttle, it won't hurt and it might help. Link to comment Share on other sites More sharing options...
dragonrider477 Posted March 11, 2008 Author Share Posted March 11, 2008 Sounds like someone put a 4-cylinder exhaust on your 6-cylinder truck. As commented above, unless you spend a lot of time at wide-open throttle, it won't hurt and it might help.i checked at napa and the catalog shows the same size 2.25" exhaust for the 4 cyl system. i think the po went to a muffler shop that made the system on a bender and the guy used the wrong size stuff.probably on purpose as the cards that come with the pipe bender tell you what size pipe to use.maybe he was out of the right size pipe that day. Link to comment Share on other sites More sharing options...
mvusse Posted March 12, 2008 Share Posted March 12, 2008 Muffler shops will use smaller pipe to save $$$. Ex wife had a geo prizm. Had Pied Piper redo the exhaust a while ago. I end up with the car, go to replace the muffler and have a heckuvatime trying to fit a stock replacement 2" muffler onto a 1 5/8" pipe! But she got a GREAT deal on the exhaust work... My Suburban had the same problem. Supposed to have a 2 1/5" exhaust. Had 2" from cat back when I got it. And my MJ? Well, it currently has swiss cheese for an exhaust system. At least that is what it resembles. Link to comment Share on other sites More sharing options...
Eagle Posted March 12, 2008 Share Posted March 12, 2008 i checked at napa and the catalog shows the same size 2.25" exhaust for the 4 cyl system. What year did you have them check? The '86 used a smaller exhaust on the 4-cylinder. In '87 or '88 they standardized on the 2-1/4" for both engines. Link to comment Share on other sites More sharing options...
dragonrider477 Posted March 12, 2008 Author Share Posted March 12, 2008 i had them check for an 88 which showed the same size for either motor Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now