yup. got the camaro oil pan, flexplate, and headers on today. still struggling getting the V12 out. its a real PITA.

i can tell you that i wont be running any cats. no need for back pressure since because supercharged.

 

I don't know if removing the highflow cats will make a difference, but removing the stock cats does. I'll try to make and post a video/soundclip with my cell and see if it will record what mine sounds like.

 

Okay, you'll have to let me know if the video works or not. I've never posted one before.
https://www.youtube.com/watch?v=cg7a...e_gdata_player

 

The video is nearly there - I see a static preview image of the rear of your XJS. When you hit the play button though, ERROR.

 

Hmmm...I can see it if I sign in as a guest, but I'm using my cell to view it. I did have to go back and change the settings from private to public though. Maybe if you try again?

 

Still the same.

 

Worked for me...

 

OK tried it in Firefox browser and that worked. Lovely barrel gauge goodness. Nice sound too, just the right amount of snarl

Just for the sake of clarification: JameyXJ6, what is your current exhaust setup please?

 

I hollowed out the 2 cat converters on downpipes and removed the innards in same pipes where they attach to manifolds. I completely removed the next set of converters and replaced them with stock sized pipes. I'm using the original, factory mufflers but removed the resonators after the axle and just put on a straight pipe with chrome tips.

It really growls at about 3000 rpm!

 

Do I have to have the 4 cats that are on the car? Can I just put 2 modern cats with two thrush mufflers and no resonators and a cross pipe?

 

You wouldn't be the first :-)

If you have emissions testing in your area you might wanna check the rulebook first but, other than that, go for it






That's entirely up to you. Many different mufflers/configurations have been tried over the years with varying results.

The crossover pipe will be useful in altering the tone of the exhaust but won't do anything for power. Apparently the firing order and breathing of the Jag V12 negates any benefit of balancing left and right sides.

Cheers
DD

 

According to the Ferrari V12 dudes, x pipes are for V8s, and 12s benefit from straight pipes.

 

Two weeks ago, I took my freshly painted XJS to the mech shop who happen to have a great stock of lengths of exhaust pipe and a sweet bender. I had wanted them to gut the two carts per side and remove the mid-muffler, leaving the tail muffler/resonator and mig up my new rectangle SS exhaust tips.
The phoned me an hour later saying both cats were already empty, and they did remove the middle muffler, putting nice shaped new 2" pipe from the ex-cat flanges back to the flange at the rear-end.-and installed my new tips. I went to pick it up, they fired it up and it was truly delightful to hear. With the Growler intakes and better breathing exhaust, she definitely sounded European, with a nice deeper tone than ANY tuner pipe car could ever dream of.
On the road, she's just a tad louder at cruise, but accelerating really is sweet, clearing her throat nicely. -And I do believe she is a bit better in accelerating now.
It would have been nice if I could have heard both options, either removing the rear resonator and leaving the mid-muffler, or doing the opposite, which I had done.

 

I have to pass emissions in Georgia on my 1990 for the next two years unless I move.

I want to know if my car will pass with one 1 aftermarket Cat on each side. I will still go with just two Turbo mufflers in the center and pipe straight out the back.

Thanks in Advance.

 

- get a PO BOx in a neighboring state with relaxed emissions?
- try 2 modern cats and see if you pass emissions?

 

Mine does... I have headers, 2.5" pipes, and 1 Magnaflow High performance cat on each side, and I pass in GA.

Dave
Atlanta
1994 XJS 6.0L Coupe

 

Thanks ATL DAVE. That is what I wanted to hear. My car is going to sound GOOD!!

 

There are no true "high flow" or "performance" cats. This is strictly an advert ploy by the companies...they are mandated by the Gov to conform to the clean air act and contain the required amount of materials/flow to conform. My exhaust guy gets every time someone comes in asking for one.

Clearing Up the Myth About High Flow Catalytic Converters