XJS ( X27 ) 1975 - 1996 3.6 4.0 5.3 6.0

USA exhaust muffler/cat removal?

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Old 05-30-2018, 12:01 AM
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Default USA exhaust muffler/cat removal?

I'd like to give the jag a little more sound... I know it goes cat, cat, resonator, muffler. Is removing the resonator the best option? I'd like more power but I assume that would only come with cat removal. Would removing the 2nd cat increase purr and power? I'm not looking for loud just a little more freeing tone. Thanks
 
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Old 05-30-2018, 12:23 AM
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The resonantors are the best choice to drop. Though even a straight pipe from cat on isn't too loud one these engines.
 
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Old 05-30-2018, 07:54 AM
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Originally Posted by Daim
The resonantors are the best choice to drop. Though even a straight pipe from cat on isn't too loud one these engines.
Ok thanks...Does removing 2nd cat and resonator keep it pretty quiet at idle, still?
 
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Old 05-30-2018, 09:54 AM
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Just leave the cats in. Waste of time removing them as they basically don't change sound, apart from droning...
 
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Old 05-30-2018, 12:01 PM
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Originally Posted by Daim
Just leave the cats in. Waste of time removing them as they basically don't change sound, apart from droning...
oh ok... you meant take out the resonators and mufflers still is fairly quiet? Yeah I don't want any droning. Been there and it is annoying
 
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Old 05-30-2018, 12:12 PM
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No, ONLY the resonators. Without mufflers (behind the rear axle) it will be too loud. JUST and ONLY remove the resonators (in front of rear axle).
 
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Old 05-30-2018, 12:52 PM
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Originally Posted by Daim
No, ONLY the resonators. Without mufflers (behind the rear axle) it will be too loud. JUST and ONLY remove the resonators (in front of rear axle).
oh ok, thank you. 👍🏼
 
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Old 05-30-2018, 04:39 PM
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I'm confused, is this based on jag service manuals or something? After the axle on the XJS is basically straight through glass packs. Typical of a straight through design that cuts down certain tones, these are resonators.

The center sections force a change in flow and cut down significantly more sound, they are mufflers.

Am I incorrect in thinking the rear components are resonators and that somehow, specific to Jaguar, the roles are reverse?

BTW with the cats in don't worry about the loudness. I have had both intermediate pipes disconnected. The transmission causes an annoying drone on the highway but i isn't remotely what I would call "loud", the 2 cats just create too much resistance.
 
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Old 05-30-2018, 08:18 PM
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I just call 'em all "muffler" and call it good . If forced to take a stand I'd call the front ones mufflers and the rear ones resonators....although it seems the rear ones do most of the work.

Typically resonators are at the rear....but not always.

On my XJS I removed the front mufflers and there was only a very slight change in tone. When I replaced the rear ones with glass packs, though, the difference was significant.

On my present V12 I have 4 glass packs and an X-pipe. I'm happy with the sound. The x-pipe helps give a pleasant tone, IMO. Without the tone is a bit....odd.

Cheers
DD
 
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Old 05-30-2018, 09:50 PM
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Originally Posted by Doug

On my present V12 I have 4 glass packs and an X-pipe. I'm happy with the sound. The x-pipe helps give a pleasant tone, IMO. Without the tone is a bit....odd.

Agreed. I don't have the X pipe and I think the sound is not at all Jaguar like or pleasant. Actually makes it sound like a worn out econobox, not a sporting car at all.
 
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Old 05-31-2018, 12:33 AM
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Originally Posted by sidescrollin
I'm confused, is this based on jag service manuals or something? After the axle on the XJS is basically straight through glass packs. Typical of a straight through design that cuts down certain tones, these are resonators.

The center sections force a change in flow and cut down significantly more sound, they are mufflers.

Am I incorrect in thinking the rear components are resonators and that somehow, specific to Jaguar, the roles are reverse?

BTW with the cats in don't worry about the loudness. I have had both intermediate pipes disconnected. The transmission causes an annoying drone on the highway but i isn't remotely what I would call "loud", the 2 cats just create too much resistance.
this is what I'm going off

 
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Old 05-31-2018, 12:47 AM
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Originally Posted by 944xjs


this is what I'm going off

And that is how Jaguar calls them. The resonantors can be replaced with the resonator replacement pipes from Simply Performance...
 
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Old 05-31-2018, 01:40 AM
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Originally Posted by sidescrollin
I'm confused, is this based on jag service manuals or something? After the axle on the XJS is basically straight through glass packs. Typical of a straight through design that cuts down certain tones, these are resonators.
The center sections force a change in flow and cut down significantly more sound, they are mufflers.
Am I incorrect in thinking the rear components are resonators and that somehow, specific to Jaguar, the roles are reverse?
You are quite correct. The rearmost silencers in the tunnels behind the axle are straight through. The main silencers with a flow change etc under the body just ahead of the axle are just as you said above.
The only car I have heard with these pre-axle main silencers removed, leaving just the tunnel straight through ones, was deafeningly noisy.
 
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Old 05-31-2018, 04:13 AM
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I might have missed something but are you talking V12 or 6 pot?
This is mine (V12) with the centre boxes removed; it's wet so the noise is a bit washed out but you should get the drift.
 
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Old 05-31-2018, 12:59 PM
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So now there's conflicting reports... removing the center preaxle "resonators".... too loud or just a bit more noise? The video above sounded nice. Is there a difference between euro and USA? There must be as the euro makes more power? I thought they were missing a cat or 2? I'm confused now
 
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Old 05-31-2018, 01:07 PM
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Originally Posted by Steve M
I might have missed something but are you talking V12 or 6 pot?
This is mine (V12) with the centre boxes removed; it's wet so the noise is a bit washed out but you should get the drift.
I am talking about a V12, and yours sound very loud to me Steve compared with an OEM car.
 
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Old 05-31-2018, 04:28 PM
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It is quite loud but not anti-social; sounds awesome in tunnels!
It can get a bit sonorous on the motorway if a lot of miles are involved but I just turn the stereo up or pull off and find a fast A road.
 
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Old 05-31-2018, 09:52 PM
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Originally Posted by Steve M
It is quite loud but not anti-social; sounds awesome in tunnels!
It can get a bit sonorous on the motorway if a lot of miles are involved but I just turn the stereo up or pull off and find a fast A road.
any interior sound vids?
 
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Old 05-31-2018, 11:28 PM
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Originally Posted by 944xjs
So now there's conflicting reports... removing the center preaxle "resonators".... too loud or just a bit more noise? The video above sounded nice. Is there a difference between euro and USA? There must be as the euro makes more power? I thought they were missing a cat or 2? I'm confused now
Most British cats until around 1990/1991 had no cats on their V12. Mine doesn't. But the cats won't change the tone, as I have yet to hear a car where with a proper cat removal, the sound changes positively. Mostly just a drone or nasty resonance at the front. No matter if 3, 4, 5, 6, 8 or what not cylinder car.
 
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Old 06-01-2018, 12:01 AM
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Originally Posted by Daim
Most British cats until around 1990/1991 had no cats on their V12. Mine doesn't. But the cats won't change the tone, as I have yet to hear a car where with a proper cat removal, the sound changes positively. Mostly just a drone or nasty resonance at the front. No matter if 3, 4, 5, 6, 8 or what not cylinder car.
well I think I'm going to give the muffler removal a try.. if it's too loud or annoying it have then put back on. Ive got a damn V12 and I just want to hear it a little more!
 


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