Does anyone know of a way to simplify the xjs exhaust system? I need to replace most of it and it doesn't make sense that there are two catalytics to replace and also two mufflers on each side to replace. Has anyone gotten it down to one on each side?

 

I haven't yet, but I will!

 

You can get single cat converters to replace the dual converters...just make sure they're legal if you have emissions testing in your area.

You can remove the front mufflers if you was a slightly sportier exhaust tone. Or you can use any combination of aftermarket muffler you want...providing they'll fit under the car.

Any good exhaust shop should be able to build a custom system for you...at a price :-)

Cheers
DD

 

The cats are there I believe because of size restrictions in the front. Now you can get smaller cats that will do the same job.

the two sets of mufflers are because this is supposed to be a gt luxury car that minds it manners.
I plan on getting straight pipe replacements for the middle mufflers. And depending on how that sounds I will decide to keep or replace the rear silencers.

Don't think of it as complicated just what the system needs. I mean, these cars are dead quiet. Be sure to get a good cat because you have a 95 and will be doing emissions for a while.

There are some places like Thedrivenman and AJ6 that offer exhaust parts and packages, but If I were you I would take off your middle pipes and either get a shop to chop the mufflers out and weld in a little straight pipe. Or do like I am planning and take them out and get a shop to make a new replacement pipe with no muffler ( I want to be able to return my car to stock).



also keep in mind when doin stuff with the XJS that the V12 does no overlap and will have no scavenging effects from a X pipe. All an Xpipe will do is blend the two banks for sound ( which is the only reason series 3 XKE have a Xpipe)

 

I had a 74 v12 E type and removed the resonators (in the rear) and got a great exhaust tone. I'm going do do the same on my XJS 4.0

 

I'm going with 48" Cobra style side pipes on my 91 XJS. I did the same thing on my 87 XJS race car (***** Whipped)but no baffles in that one. A 5.3 V-12 through 3.5" side pipes is one intimidating sound on the track. A complete removal of the extraneous systems off of the engine and two custom fit K&A air filters gave me quite a boost of HP rather inexpensively. It's a race car so the intakes are hood/throughs under two scoops. Really keeps the heat down too. Two radiators and two transmission coolers helps too.

 

I have always wondered if gutting on deleting the cats would set of a code on the 95 4.0 cars.

 

I suspect it would depend on the year of the vehicle. I did it on my land Rover with no issues at all. Runs great and sounds much better too.

 

Here in CA the smog test is "not fun"

I've just got my car back after a full 4 cat replacement to get past the test. I used 4 high flow cats. My exhaust man was convinced the car would pass with only 1 cat per side, however, we agreed to stick with 4 as you can fail here for not having the right number (regardless of your actual emissions readings)

PS they also wouldn't smog the car with aftermarket aircleaners (growlers) even though we actually ran it both ways and the emissions were LESS With the aftermarket set up