Originally Posted by 96xjcountry
Whats is the difference between the 87-92 cherokee exhaust and the 93-01 cherokee exhaust systems?
1987-1990 w/242ci will have provisions for the EGR system (I've never approved - there are better ways to go about what the EGR does that are more reliable and cleaner in operation...)
1991-up will not
have provisions for the EGR.
The bend of the downpipe (between the header and the cat) may have changed with the introduction of OBD-II, I'm not sure. That would be 1995/1996.
OBD-II saw the appearance of "Downstream HEGO sensors" to monitor catalyst efficiency - this happened at the beginning of the 1996 model year.
The advent of the 0331 head (2000-2001XJ, 1999-2006 WJ/WK/TJ) saw the introduction of an exhaust manifold with "pre-cats" - catalytic converters inbuilt into the manifold. One for cylinders 1-3, another for cylinders 4-6. And this manifold is a spendy
If you need anything more specific, let me know and I'll see what I can dig up.