Exhaust Tone
#1
Exhaust Tone
My 4.2L Coupe just doesn't have a proper voice. It's very sedate sounding; not befitting its looks. I have the stock Jaguar exhaust manifolds (which I'm not changing) and the stock twin "silencers". So there's a Y pipe off to front silencers with a rear silencers behind that. So four silencers all together. Forward of that Y pipe there is a Cat converter that a PO added for some reason (as there are no other emission controls on the car). I am eliminating the cat converter, replacing it with a straight pipe, so I know that will make some difference in sound. Maybe even in a little more HP. Has anyone experimented with any other systems that give the car more audible attitude? I'm not looking for a hot rod, or really bad *** sound. Just something a bit more raspy and tone-al... a little more growl and a little less meow. I've had the two rear silencers off when painting the rear valance but that didn't seem to do much (the Cat converter was on at the time). Thoughts?
#2
#3
In essence, you have what became to be known as a cat back dual exhaust system. Faux, when related to a true dual system.
The exhaust manifold on these cars is not bad at all. Note the two outlets !!!
Were I to consider an all out redesign, I'd start there. One from each outlet back to the silencers aka muflers. Include an X or H pipe to eliminate raspy harmonic. Eliminate the rear silencers, aka resonators. Whoah, that is pretty close to the system used by jaguar for the famed E type.
Dependant on the design of the Cat, removing it will alter the tone. Older units more restrictive and thusly quieter.
My "different" car has a true dual exhaust system with twin cats. An H pipe, stock jaguar front mufflers and small glass packs in the resonator position. It has a nice burble. Clear that it is V8 powered, but not obnoxious.
Carl
The exhaust manifold on these cars is not bad at all. Note the two outlets !!!
Were I to consider an all out redesign, I'd start there. One from each outlet back to the silencers aka muflers. Include an X or H pipe to eliminate raspy harmonic. Eliminate the rear silencers, aka resonators. Whoah, that is pretty close to the system used by jaguar for the famed E type.
Dependant on the design of the Cat, removing it will alter the tone. Older units more restrictive and thusly quieter.
My "different" car has a true dual exhaust system with twin cats. An H pipe, stock jaguar front mufflers and small glass packs in the resonator position. It has a nice burble. Clear that it is V8 powered, but not obnoxious.
Carl
The following 2 users liked this post by JagCad:
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yachtmanbuttson (07-25-2018)
#6
Cats are good for creating heat. Nothing else.
I liked the sound of my old 4.2, mostly due to the ample leaks in the pipes.
Did find that the muffler under the rear seat has a heat shield over it, then a layer of fiberglass(?) insulation. Did a fine job of rotting out the bottom of the seat pan.
No worries, had it cut out, cleaned up and patched shut in a matter of a couple short nights work.
Moral of the story, remove the mufflers under the seat (forever), the heat shields & any other insulation, and inspect for rust. The rear silencers replaced with adequate glass packs will give a nice, slightly aggressive growly sound.
It's much worse than it looks.
I liked the sound of my old 4.2, mostly due to the ample leaks in the pipes.
Did find that the muffler under the rear seat has a heat shield over it, then a layer of fiberglass(?) insulation. Did a fine job of rotting out the bottom of the seat pan.
No worries, had it cut out, cleaned up and patched shut in a matter of a couple short nights work.
Moral of the story, remove the mufflers under the seat (forever), the heat shields & any other insulation, and inspect for rust. The rear silencers replaced with adequate glass packs will give a nice, slightly aggressive growly sound.
It's much worse than it looks.
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Andy Paine (08-05-2018)
#7
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#8
When, quite recently, in colder weather, my "pipes" seemed to emit a generous amount of a white vapor, son and I suspected water in the front mufflers. The angular mount does suggest that. Son got under and with my sharpest Cobalt small drill bit put two holed in the lowest part. Odd, no water dripped out !!
A flaw that did not exist!! Seems so. 30+ year old mufflers still sound.
Carl
A flaw that did not exist!! Seems so. 30+ year old mufflers still sound.
Carl
#9
#10
in my '84, I deleted both cats but not the mufflers. The sound did not change much at all, slightly more growly but nothing to write a book about it. Horsepower-wise, not any noticeable change.
Heat wise? yes, a very noticeable decrease. The driver's side floor does not get hot anymore. Dammed cats!
I think the main issue is the engine: the 4.2 is a quiet engine.
the US Federal Y pipe has a secondary cat right at the Y intersection in the Series 3, the Euro pipe does not.
also the Euro down pipe (the one that connects to the two manifolds and to the Y pipe), does not have a cat.
you can get both Euro pipes in the US. I got mine from Motorcars Ltd. in Texas.
Now if you hear my '65 S type with a 3.8 liter engine and a stainless steel Bell Exhausts Ltd. system, then you will hear a Jaguar. It sounds like the old XK-120 Jags.
Why the difference if both exhaust systems are nearly identical? I have no clue.
Heat wise? yes, a very noticeable decrease. The driver's side floor does not get hot anymore. Dammed cats!
I think the main issue is the engine: the 4.2 is a quiet engine.
the US Federal Y pipe has a secondary cat right at the Y intersection in the Series 3, the Euro pipe does not.
also the Euro down pipe (the one that connects to the two manifolds and to the Y pipe), does not have a cat.
you can get both Euro pipes in the US. I got mine from Motorcars Ltd. in Texas.
Now if you hear my '65 S type with a 3.8 liter engine and a stainless steel Bell Exhausts Ltd. system, then you will hear a Jaguar. It sounds like the old XK-120 Jags.
Why the difference if both exhaust systems are nearly identical? I have no clue.
Last edited by Jose; 07-26-2018 at 04:07 PM.
#13
that is the one I installed in my '84 years ago. Had it shipped to Jet Hot Coatings where they coated it with their Sterling ceramic + silver coating to reduce the exhaust temperature. Works great. Also had the two over-the-cage pipes done. I had the front cat opened, striped, and rewelded so it looks like the cat is there, but mainly because of the O2 sensor, since the Euro down pipe shown in the image does not come with the O2 sensor mount.
#14
That's it. Almost causes me to want to light up my torch, cut some pipe, and weld some in.
Two outlets from the manifold go into one and then split in to two. Connect the second outlet direct and have two true dual pipes all the way astern. Caveat, it mitht rap and an X or H pipe would help.
Or, way back, I added a 6 into one header and a longish glass pack to my 69 Toyota Land cruiser. It's similar sized six sounded nice.
Jose:
Why is the XK engine quiet as to exhaust tone. I've noted in past critters, that raising compression creates a sharper bite. And, of course displacement. Big inches bark loudly...
Carl, .
Two outlets from the manifold go into one and then split in to two. Connect the second outlet direct and have two true dual pipes all the way astern. Caveat, it mitht rap and an X or H pipe would help.
Or, way back, I added a 6 into one header and a longish glass pack to my 69 Toyota Land cruiser. It's similar sized six sounded nice.
Jose:
Why is the XK engine quiet as to exhaust tone. I've noted in past critters, that raising compression creates a sharper bite. And, of course displacement. Big inches bark loudly...
Carl, .
#15
Jose - that is my other option regarding the CAT and that is to open it up, gut it and reweld it. It's rattling when I shake it anyway, so I think it's toast. I don't have an O2 sensor so that's not an issue. That would be my most inexpensive option moving forward. However you say that it won't make much difference gutting it and still leaving the other four stock silencers in place? Will it still heat up with it gutted?
My other option as I mentioned previously was to remove the CAT altogether and install a Y-pipe like the Cherry Bomb 429825 below.
My other option as I mentioned previously was to remove the CAT altogether and install a Y-pipe like the Cherry Bomb 429825 below.
#16
1. Old tech lives on. Gutting the cat is similar to what we used to do with mufflers. Cut them open remove the guts and weld them back. As for the gutted cat, it might make a smidgeon of difference as to sound. It will no longer get "cat hot". It is no longer a cat, merely an open chamber, ala gutted muffler!!!
2. If the cat rattles, it is done for. Dump it for the Y pipe or gut it. It isn't cleansing the exhaust any more.
Carl
2. If the cat rattles, it is done for. Dump it for the Y pipe or gut it. It isn't cleansing the exhaust any more.
Carl
#17
That's what I thought - I'll gut it - cheapest way out. It's no good anyway. To keep things on the cheap, the next thing I'll probably try is to eliminate the front most silencers with a straight pipe and see what that does. I'm about to spend $5,000 on a paint job so the bills are racking up.
#18
Carl I don't know why the 4.2 engine is so quiet. Compared to the 3.8 engine which likes to growl even with the 5 muffler factory-spec system that I installed.
Yes, 5 mufflers, identical to the XJ factory system but with an additional silencer at the front of the Y. Loud like an old Jaguar from 1952.
when the car reaches 82-83 mph, the engine and exhaust become almost silent. The "sweet spot" I guess.
but the XJ is always quiet if not silent.
Note that the stuff inside the front catalityc is very toxic. I had my mechanic open it up then he gave it back saying "You clean it then bring it back, I'll seal it". So I did it underwater with gloves. There is a honeycomb mesh bag inside with platinum and I don't know what else, but it is toxic. The bag is spot welded to the inside of the canister.
Since removal of the cats, the engine exhausts better and runs cooler. Less obstruction.
Yes, 5 mufflers, identical to the XJ factory system but with an additional silencer at the front of the Y. Loud like an old Jaguar from 1952.
when the car reaches 82-83 mph, the engine and exhaust become almost silent. The "sweet spot" I guess.
but the XJ is always quiet if not silent.
Note that the stuff inside the front catalityc is very toxic. I had my mechanic open it up then he gave it back saying "You clean it then bring it back, I'll seal it". So I did it underwater with gloves. There is a honeycomb mesh bag inside with platinum and I don't know what else, but it is toxic. The bag is spot welded to the inside of the canister.
Since removal of the cats, the engine exhausts better and runs cooler. Less obstruction.
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Jahmiata (08-11-2018),
yachtmanbuttson (07-27-2018)
#19
#20
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