My car is a XK 2007, 4.2 lt N/A.

I am very happy with it!

I am also happy with the sound, but one is always looking for improvement ;-)

What I do not get is:

the typical V8 sound is generated by a double exhaust, and because of a cross plane crankshafts ignition order:

"The cross-plane crank has an irregular firing order, sometimes producing two exhaust pulses on the same side, as opposed to alternating. This irregular firing sequence is what causes the deep rumble of an American V8 (cross-plane) as opposed to the rhythmic, even pulse rate of a Ferrari or Lamborghini V8 (flat-plane)"

Now, what does an x pipe? If the two sides of the exhaust are combined, the typically V8 rumble is gone. Maybe it generates MORE noise, because it´s a custom job deigned to be more noisy, but IMO the x pipe kills the beloved V8 sound? Maybe an x pipe sounds like more cylinders, but I prefer the V8 rumble.

Please tell me more about this.

Also interested in the best exhaust system, I am not looking for racing rookie sound, but the best V8 purr, rumble and growl.

And please a flap exhaust, as in the future the regulations are for sure getting tighter ;-(

Thanks in advance, Hermann

 

Maybe just add a h-pipe near the front of the mid pipes, retain your original resonator and you'll still retain that V8 rumble you like

Photos below are a reference as to how it would look with h-pipe

 

I’m happy with the sound I get from my 2007 XK n/a after replacing the back box with one from a 4.2L XKR.
The ‘flaps’ are open by default, so a nice tone is always generated. If worried about the authorities, it’s a genuine Jaguar OEM part, not aftermarket.
Somewhere on my ‘todo’ list is to add control over the flaps, either by obtaining an XKR vacuum pump, or experimenting with servos or stepper motors to electrically control them.

 

The uneven firing sound from a cross-plane V8 is a feature of the cylinder firing order rather than the exhaust configuration. Even if all the 8 cylinders fed into one pipe, you would still hear the uneven firing. However, the exhaust system does obviously affect the overall sound of the engine so you can select a system which sounds best for you but the presence, or lack of, a cross-pipe will not be the main determinant.

Richard

 

the x pipe design helps scavenging especially at higher rpm increasing hp,,the higher the rpm and horsepower the engine has originally the higher the improvement with an x pipe ... Comes down to what more important to the cars owner,, sound or power.

 

Exhasut Performance System : Exhasut X-Pipe & X-Pipe Exhaust
""It has been proven time and again that the X-pipe design is more efficient than the H-pipe. Various tests have shown that for multiple cylinder engines the X-pipe outperforms H-pipe exhaust systems, especially as rpm increases, providing both better torque and power""

 

Please keep me informed, Sir!

I for sure want to be able to control the level of motor sound ... e.g. starting Sunday morning in a nice, quiet neighborhood, or if there is a traffic control ...

;-)

Hermann

 

I think my X-piped XKR sounds pretty sweet.

 

Several member have fitted the XKR quad back box with good results to their XKs. There are some aftermarket exhaust valve controllers available.

 

It depends what you want, personally I went with a custom exhaust
job that looks identical as the quicksilver exhaust system, but instead
of a resonator, I have an X-pipe. After doing this you definitely need
a ECU remap/tune to get your car to run properly and sound good as well.
nothing is worse than a improperly tuned loud exhaust.

An X-pipe will sound more like an aston(IMO), smoother refined sound.
Personally I don't like the mustang-ish v8 rumble that an H pipe or
other options have.

 

Nope, well not a V12 one anyway

There was a slight increase in volume when I added an x-pipe to my '10 XKR but it mainly changed the pitch (higher).

 

The only astons ive heard in person are v8 vantages which
share a similar engine to the XK.

 

Astons are one of the most common cars in my car and coffee club so I hear the V8 Vantages a lot and you would need more than just an x-pipe to mimic their sound, certainly in volume anyway.

Coincidentally this was posted on one of the Aston forums a few days ago and is quite an interesting read on how they arrived at the exhaust note on the Vantage.

 

Correct, an x-pipe alone will not do much for sound. and ECU tune and new muffler or muffler delete.

that PDF is pretty insane, thanks for posting!

 

One of the largest Sound Modifiers is to go to 200 cell Cats. That'll hurt your earballs.

 

Sounds like you got a video to share?

 

Not me, man. Others have done this though.

 

Try 100cells ! Now that's loud I have my back box set up to have the outer exhaust valves in the closed position to reduce sound.

400s would be the sweet spot for these cars

 

My 200 cell cats crumbled to dust so now the cat's catless! It's louder but then it was loud to begin with since the back box delete.

 

Definitely not for the faint hearted^^^