Sound difference adding second crossover pipe to exhaust?

Has anyone ever installed 2 crossover pipes to their exhaust? Just curious how it altered sound?
I recently added a curved shaped crossover and it really did help even out sound but thought it would be fun to try adding another further aft.

I’m not really sure why you’d want to add a second x-over pipe. As I’m sure you’re aware, the purpose is to even out the exhaust pulses between the banks; and in theory creating a vortex to better extract the exhaust from the cylinder chambers thus creating more power, as well as smoothing out the exhaust pulses. In a perfect world, (sans a catalytic converter) the cross over does just that - even out the pulses, and at lower and higher RPM ranges. However power gain is minimal.

I’ve, never fitted a cross over to a Jaguar, but I’ve done many to American domestics; there is a distinct sound difference between no cross over, cross over, and X-pipe. personally I always went with an X - pipe configuration over a generic cross over or some variant of an H pipe…

I’ve included a link of a video from motor trend TV. The video puts numbers and science behind my experiences with domestics. In short. Nope never done it, Not sure why’d you want to put yourself through the extra work; I don’t think you’re going to see any benefit.

It would appear there’s been some modifications to this car. The exhaust seems to be going in a different direction, as well as some boxed steel reinforcement(s); also some extra fittings on the transmission cooler lines.

I agree Mark in theory it does not make much sense however what if it might and if it might then I am willing to go through the trouble. If I put another smaller diameter pipe in between I’m wondering if maybe it may disrupt the airflow enough to give it a unique sound.
Yes you’re right good eye it has had modifications it does have leg pipes and a 700R4 and the rear end has a dually axle.

I think you will get a unique sound. Depending on where and the inlet angle you’re going to install the cross over will make a difference. Based on what I can tell from the picture, it looks like (from the picture) the cross over is going to be the lease that of resistance in regards to flow (about a 60 degree angle as opposed the exit at 90 degrees). then when the RPM’s get up a bit, then the exhaust will compress in the cross over… This will be interesting. I’d love to read the report after your done.

How far away are the tail pipes from the cross over?

Wow, Serious mods. Why the Dually?

I will report when I do this. Hmm. I would say the exhaust tips are about 4 feet from cross over. I do love the sound now, and it sounds even better when brought above 4K rpm, but if I made another small crossover as well, it may help the sound note at lower rpm. Guess I will find out.
Dually for towing.

OMG: that thing is so DAFTLY over the top…

I love it!!


In a normal V8, the two banks don’t fire at the same time, so a crossover pipe has a benefit in terms of power - you are in effect reducing the resistance to a pulse by doubling up the exhaust.

In a V12, the two banks DO fire at the same time, so there is no power benefit to a crossover pipe.

1 Like

slightly off topic, i agree with wiggles. now i am curious about what you tow behind, guessing it is not average either. ?

1 Like

Wow, those are some serious mods, nicely done. What did you do to the engine? ‎To warrant the hood scoop?

1 Like

I will post a separate subject. A lot of people have asked. And no it’s not anything typical.

I didn’t know that, good to know. Of course now that I think about it; it does make sense that there’s gotta be something firing on the other side. I haven’t delved into my V12’s yet. I’m up to my A$$ in XK6 issues. mainly the Clapped out Series II (many a posts in the XJ forum).

1 Like

Excellent, tag me in the post so I will know when you do it. I’m intrigued.

Check the subject “Why did that crazy guy make his Jag XJ-S a dually?”

can you explain how the two banks fire at the same time please

The v12 is basically two 6-bangers at 60° with a common crankshaft.
For every cylinder on bank A at TDC, there will be another on bank B at the same position

It is always A-B-A-B.

v8 for comparison is NOT two 4-bangers at 90°, common order for firing in this case would be:

Hope this helps

1 Like

yes, but the cylinders are still firing 60deg apart

Just have a look at the distributor cap.
All ignition leads are spaced evenly and 30° apart, i.e. 60° of crank rotation.


1 Like