jeepforlife

the exhaust manifolds on a 92 xj? And... does removing the catalytic converter improve performance on the 4.0

Firestorm500

There is only one exhaust manifold. The intake and exhaust come off together, the engine itself stays in.

Removing catalytic converter(s) is a violation of federal law and could be a $10,000 fine. Don't do it.

jeepforlife

oh perfect... its my wifes jeep and she wont let me touch it hahaha.
I had no idea it was a federal law... holy smokes thats alot of money i can use for my jeep

Firestorm500

If you are not pretty sure and experienced around the engine, I would take it to the dealership or a reputable mechanic shop.

Pay the money to have it done right (the exhaust manifold). Inexperience can break something bad real quick. Learn on something easier to do.

If the dealership breaks something, they have to fix it.

I just saved you 10 grand--you have plenty left over to let someone else do the work!

98 JeepJeep

IMO removing the header is cake. if you have some wobble sockets and plunty of 3/8's extensions your golden. throw a 99+ intake manifold on there while its apart.

JeepingDan

heres what you got after the intake is off

jeepforlife

Thanks guys. I am pretty confident in myself to remove and replace. For some reason the wife thinks I want to soup it up. hahaha.... so the 99 cherokee will fit it? what makes it better then the 92?

RedBaron

About 30 H.P.

5-90

The 1999 manifold is a better design than the 1992, and yes it will fit.

Removing the catalytic converter is a violation of USEPA regulations, and you can get seriously clobbered for it (as mentioned.) If you want to open up your exhaust a bit, you can use a "larger" catalytic converter (one made for a higher-displacement engine) instead, which allows you to maintain catalyst function while supporting more airflow. I typically use cats for big block Chevvy engines under my rigs, right in front of a very mildly restrictive (and fairly inexpensive) muffler. It opens things up a bit, seems to improve throttle response, and gives me a nice growl without sounding like a tractor with a thyroid problem.

Face it - the dynamics of the engine won't let it sound like a good throaty V8. But, it won't sound like a weedwhacker with a kazoo rammed up its ****, either (cylinder displacement is too large. Each cylinder for us runs a touch over forty cubic inches displacement - more for a stroker - and a litre is just over sixty-one. You get the idea - two litres = ~122ci ~= three of our cylinders, and our engine has larger exhaust pulses driven out at a lower crankshaft speed.)

No, you don't have to pull the engine to replace the intake &/or header. A 9/16" 'flex' socket will help immensely (shorty socket with an inbuilt universal joint) along with a couple of longish extensions. However, if the head has to come off for whatever reason, I'll usually leave the manifolds attached, remove the head and manifolds as an assembly (takes lots of muscle or mechanical advantage. I can get away with it because I'm a size extra-extra-large myself, with arms like an ape...) and service the manifold gasket on the bench alongside the truck. Way much easier!

ol"blue

^X2. Great advice 5-90, and an excellent post.

leethedeuce

Hi,
I was just wondering if you when you upgraded to the 99 manifold. Is that any 99-05 manifold? Are any other special parts required? different injectors or throttle body anything? Can anything of that newer stuff be used and be beneficial and just a bolt on installation? Just put on new alternator and did a bunch of other stuff. manifold is cracked above a weld...typical...167k...So doing a few things at once and would like to get it all right. passenger side u joint and inner axle shaft was done last year and now doing driver side as well. along with some motor/tranny mounts. I believe the tranny one is bad
Thank you for your time,
Lee

whowey

And with the last two posters... this thread is now on the clock.....

Too bad they had to screw it up. 5-90 put some really good info in here. Thanks for trying Jon.

COSXJFAN

No posting, hypothetically or otherwise, about removing emissions control equipment, PERIOD!! Anymore talk of this, and this thread will be closed!

93gc40

It's Illeagal to run without the Cat. I most cases, without other modifications, ie Computer controls, Performance will be hurt by removing the Cat from the system. Free-er flowing Cats are a vailable, and is a must if you want to improve exhaust flow. Without a free flowing cat, exhaust mods are for sound ONLY. Exhaust alone is only good for 5-10% HP gain if you are lucky.

DJKnightmare

Can you put a 99+ intake manifold on a 1990? How about the exhaust?