I have a V12 XJS. Removed the cats, and have straight pipes that go to the rear resonators. Did mid res delete. Feel like exhaust sounds a lil.... lawnmower-ish. Wanted to see if folks have any advice on tuning that sound.

 

The lawn mover sound is because the pipe diameter is so small and has so many sharp bends over the axle. You would need 2.5 to 3 inch pipes that are somewhat straighter to get a deeper richer sound. Think pipe organ. The inboard brakes and limited clearance under the IRS precludes the use of larger diameter pipes. Hey...there's always side pipes.

 

Many, many before you.....myself included.... have tried getting the "v12-ish" sound (if that's what you're after) with little success. More sound is easy. The right sound, as you are finding out, is not. People who know a lot more than I do insist that the firing order and inherent breathing/exhaust dynamics make the task very difficult.

The best (and very pleasant) tone came on the V12 E-types. I would suggest researching and trying to duplicate that system as closely as possible...including the crossover pipe....which Jaguar used solely for the purpose of getting the right sound. Not a rumble, not loud...but a mild snarl that sorta turns into a howl.

Cheers
DD

 

I thought sidepipes would look great on my 89 xjs conv. Have you see or heard these.

 

Thanks guys... Always a bit of experimentation.
Think this plays back into my other thread. Manual trans. When I play around and run this in first or second gear on automatic, the sound is so pleasing at higher revs, and I get that nice crackle when I back off the gas at higher revs. When you're running in "D", IE 3rd gear, you get the low rev hum, and not the "V12 sound". My jag guy said that even tips tune sound. Have heard conflicting accounts on this (and kinda like the stock stainless s tips)

 

After experimenting with different set ups I eventually ended up with these:

Turbo Tube 2 25" x 20" Chambered Muffler | eBay

I had them in the rear most position, nothing in the forward position. I was pretty happy....pleasant growl, no drone, not overly loud. But not 'that V12 sound' either.

Never did get around to adding the crossover pipe.

Cheers
DD

 

The Jaguar V-12 is really a Double 6 and therefore will never get that V-12 sound so many seek. Just isn't going to happen.

 

My car being an Australian 83 was never installed with cats, so that was one thing I didn't have to worry about.
The first thing we tried is deleting the rear resonators with the exhaust shop bloke just using straight pipes, it sounded woeful! we ended up putting in two 12" HOTDOGS just a different form of resonator, but actually gave a nice deep rumble. When I do the motor change I am looking into headers and larger pipes, Ill have a play with the middle mufflers and see what I get, but for now it doesn't sound to bad at all. I also removed the two air intake trumpets, so when you put your down you can definitely hear her coming but all the noise is from the front end.
Side pipes would be awesome but my wife would hate them, and due to the laws they can only be on the right hand side.

 

I've had 2 V12s with the centre boxes removed and they sounded pretty good, especially going through tunnels.
Also an excellent way of setting off car alarms!

 

I changed to intake and agree this greatly enhances the wound at high revs. Is the engine architecture that different from other v12s? I thought this engine was built from e type Base.

 

This is the sound I got from gutted cats going into 2-1/4 pipes. Flowmaster Delta 40s in front of the rear axle, pipes running under the diff, then out through dual-tipped Monza resonators.

Idle & Rev.wmv

3000rpm Drive-by.wmv

 

I love it

 

Sounds great !


Cheers
DD

 

Any drone at highway speed? That'll take the fun out of things in a hurry! Do you have a model number or pics of the Monza tips?


Cheers
DD

 

bump doug's question

 

Yes, same as the E-type v12 which itself did not have quite the "V12" sound that many expected.

I've never really studied the science of it but the firing order and degrees of rotation between combustion strokes ....or something like that...is why the Jag V12 doesn't have that howl that we've grown accustomed to hearing from Ferraris and the like.

Someone mentioned that the Jag V12 is really a 'Double Six"....like two individual inline six cylinder engines with a common crankshaft. That's sorta what I'm driving at.

Hopefully someone will come along and explain it properly.

(Sorta like when you're making introductions and you forget a person's name....and you pray, pray, pray that some astute observer will recognize your dilemma and gracefully bail you out!)

Cheers
DD

 

The ferrari sounds is due the shape of the exhaust and the rpm at which its held at. Ferrari 12s sound pretty exceptional at WOT but not at idle or half throttle.

The Lamborghini countach (pics to prove this) I was in the other day didn't sound much better than the xjs without downpipes.

Also lets remember lambo and ferrari motors have so much more cam than these jaguar v12s do. 300bph from 4.4 liters. And 500hp from 5.2 in the countach 5000 qv.

 

As far as adding a H pipe, I wouldn,t I actually like to listen two the two banks individually, lets me know if there is something going wrong.
I sort have a different sound that I prefer the car make, personally I do not really like the Ferrari type note, as said it may sound fine wide open but we never seem to drive our cars like that. I realise its being discussed before but to me the best sounding XJS I have heard has to be this one If I could get mine to sound like that just toned down a little, now that would make me happy.

 

I run an "H" pipe just aft of the trans and fwd of where my mid mufflers used to be, horrid drone at freeway speeds after emptying cats and removing mid-mufflers...drone gone once "H" pipe installed.

 

Sorry for the delayed reply. I knew that I had some old sound clips of the interior sound at various speeds, but, I had to convert them to WMV files in order to attach them with my reply. There is a little bit of drone between maybe 1600 and 2000, but, it's not overbearing (it's been a little over 5 years since I've driven the car, so my memory is a bit fuzzy). I'm not sure if the sound will be different with the new motor. Hopefully I'll find out sometime in the next couple weeks. These sound bytes aren't the best, but, hopefully they'll give you some idea.

40mph.WMV
3000rpm 80mph.WMV
6000rpm 105mph.WMV

Here is the link to the Pacesetter Monza Resonators:
http://www.summitracing.com/parts/psm-95-9905/overview/