I noticed today that my exhaust is stronger from my driver side (A Bank) than the passenger side. I believe the driver side cats may have been cleaned or gutted since I noticed some weld marks on them. I would like to get rid of the cats all together. I'd like to get the thoughts of those on the forum. Should I gut the cats or go with a new stainless system. The biggest problem I see is that I have to do this work myself since no exhaust shop can legally perform the work. I would love to hear some experiences in this area.
Thanks...Jimmy

 

My xjrs engine pipes are cat free so l can't advise specifically on them but l have 4.6 hse range rover on which l gutted the cats. Performance and function is fine but the empty chamber left behind after gutting makes them sound terrible.
I would recommend going to non cat engine pipes. Mine were made by Bell and are a work of art.

 

I have gutted cats on my 86, not hard to do, sounds fine ( also removed the mid mufflers) big issue is the blockage at the top of the down pipes, I'n removing that I got to where I can have the down pipes down on a V-12 in 30 mins (first time not so much)

 

I'd like to know where I can get exhaust pieces that fit (with or without cats) that don't have to be custom made.

Padre

 

The A bank is RH side of the car. If yours is a LHD car the drivers side is the B bank. You need to make sure the A bank is firing on all cylinders.

DO NOT GUT THE CATS, unless they are the ones inside the down pipes. Doing so will hurt flow.

If the exhaust system is still in good condition then I would replace the Cats with high flow units, this will keep the car legal and in a road car not effect power very much.

The down pipes are very restrictive and I have heard from numerous V12 engine builders that where the pipes are joined there is more often than not intrusions of one pipe into the flow region.

 

The engine runs fine, firing on all cylinders. My state doesn't have inspections, so I am not concerned with being legal. I don't want to replace the cats because of the cost. I will probably just gut the cats since that seems the easiest and cheapest way to go.
How difficult is it to remove the down pipes, does anything else have to come off in order to get them out?
...Jimmy

 

You'll need to pull the steering rack heat shields (super easy) spray some PB Blaster liberally on the nuts and just use some extensions and deep well sockets, really not hard to do. I put all four of my tires up on ramps and jacked up the front even more to allow comfortable room. Sprayed them down and waited till the following morning. Jaguar uses a steel, long nut with a brass locking insert so corrosions not usually an issue unless someone's been there before and improperly replaced them.

 

I also pulled the exhaust from the back of the cats. Mine is easy as the mid mufflers are removed and I have an "H" pipe welded in so it comes out as a unit.

 

JTsmks....I checked the workshop manual and the 5.3 and 6.0 have very different exhaust systems. My 94's down pipe has an extra cat in it (lucky me!). I will probably wait till fall to start this project, just to hot this time of year. I plan on a complete cooling system overhaul also. I'll jack her up and get it all done at once.
Thanks to all for your inputs...Jimmy

 

Way back in the precat era, kids wanted exhaust noise. An "on the cheap" way was to "gut" the mufflers. And that was done on the cheap by some. Remove them and use a stout bar to knock out the cambers.


A bit more sophisticated way was to cut them open, remove the baffles and reweld the case.


I had a couple of 36 HP VW's back in the day. first a 56 small window sedan and then a 60 Red cabro.


I wanted a little exhaust tone. Each had two chrome tips from transverse muffler. In turn the tips had a bit of lining. MNaking them a bit of a silencer. I used a big sharp screw driver. Inserted into each tip. A few whacks with the BFH. Chamber punctured. Much better...


Carl

 

But, cats do work. Modern ones are much less restrictive. I like clean air as much as anybody. So, my cars have them.


The V8 has a true dual exhaust. Two cats, then an "H" pipe, two
Jaguar mufflers, and then two small glass packs. Curved Jag tips in place. It pours very contentedly and reveals it is indeed a V8, not a six!!!


Carl

 

He doesn't want to pay for new cats and doesn't seem to care about the environmental impact.

Do you have an IR thermometer? Measure the temps before and after the cats and you will know if they are working, and in this case whether one is gutted.

 

Thanks for the tip My Jeep is coming up for SMOG inspection.
The usual fail is because of worn out cars. It is on it's second one.




I do have an IFR. so, after it's hard run before the visit, I'll check on the temps.I


Carl

 

Thanks again...


I've no issues with most emsion control devices, except the stupid air pumps!!I


Carl

 

Thanks...don't know why I didn't think about checking the cat temps. It'll be interesting to see the results. I'll try to get to it tomorrow.

JagCad...agree about the "stupid air pump", it's going to disappear from mine soon!

Jimmy

 

I'm curious, why do you think cats are a good idea but air injection is stupid?

The less your use your IR the more you forget about it, but it is a great tool to have in the box.

 

Correction...

 

Efficiency has gone up a lot from things like variable valve timing and most cars now, including your new acura, use EGR instead of secondary air injection.

I had to check my cars emissions once, and they were incredibly low. Do you have some info that convinced you that secondary air injection actually doesn't burn excess fuel in the exhaust like it is meant to or that the catalytic converters in the XJS don't decrease harmful emissions?

 

Thanks...Jimmy

 

No, they work. Or worked, past tense. As the decades go by some of the systems on old cars are no longer working properly, no doubt.

But as the years went by automobile emissions really DID go down in the grand scheme of things... even if some of the early attempts were not all that great compared to what we have now.

Talk to someone who lives in a big city (like Los Angeles) in 1965 and ask them to compare air quality to 1995. The difference over 30 years is remarkable.

Cheers
DD