that's odd Larry, I did that exact thing to my car, including the magnaflow x-pipe, and I don't get any resonation. Is the x-pipe as far forward as possible? Switch it to an H-pipe, it'll be a little louder and perhaps rid the resonance.

 

I am surprised you get resonance as removing just the centre box should not cause this, you still have the resonator boxes which are at the back? Whoes job it is to stop any resonance.

This is why if you remove the rear boxes completely and have nothing at all the car will not sound that much different, putting the straight through pipe on acts like a trumpet and amplifies the sound giving a better note but you will then get some resonance and the bigger the pipe you go the louder/stronger the resonation.

When I make a system up (not that I do anymore I prefer yo use Blue Flame Exhausts) I would always have an X pipe 2 smaller boxes in front of the cage and then 2 resonator boxes at the back, this would produce a unique sound similar to Aston Martins. Something else you need to bare in mind if you make your XK too free flow you will lose power down the lower end of the rev range and it will only make power over 3000rpm.
When I was first experimenting I even tried a dual system, total disaster, the car ran like a POS, I then went with the balance pipe which produced a nice pop/crack on the over run. I also tried big bore tube up to 3" dia, this also did not work well and the best size was 2 1/2 to maintain lower down power. As I mentioned earlier X pipes produce better power H pipe produces a better sound, this is of course IMO

 

Guys:

I may be characterizing the sound incorrectly. I really don't think it is resonance, but the sound while accelerating through the 1500 to 2500 rpm range has a higher pitch than I expected and that's why I call it a buzzing or sort of humming. It sounds kind of wimpy to me.

XKRacer - thanks for the input regarding Blue Flame. Any particular model or do they only have one sound level availavle? I haven't done any research on them yet. It may be obvious when I do.

Also, it sound like eaglexkr's sytem has only the resonators. Seems like that might be a little too loud for my taste. ???

Thanks -

 

They have just one system with just varying tail tips, the large ovals look the best. They are revamping their website at the moment so it is not very informative but I can recommend the system, well made and sounds good. You will just need to find a US stockist

Wimpy is not good unless we are talking hamburgers Could you make a sound recording of it and post it up? I'm kinda curious now.

 

I really like my flowmasters (I think I posted a link earlier in the thread to my post which has videos..that don't do the sound justice) They produce a low almost echoing tone with very little drone. I used 40 series which can be a bit loud. I wonder if 50 series would be a good compromise for you guys wanting a deep tone without getting too loud?

 

Okay first I would like to say that I was happy with My XKR with the standard exhaust until H20Boy and others started modifying the exhaust systems on their cars. Then I heard an Austin Martin getting up to speed and like the more aggressive sound.So I went back to the forum to see what others had done and decided that it was time to jump on the bandwagon and make a change.
With that said,I talked to our independant Jaguar shop and he sent me to a guy that does exhaust systems for custom cars,Mustangs,Corvettes,BMWs etc.It was his idea for me to put in the x pipe and remove the center muffler and back boxes and run 2.5 pipe up til we got to the factory pipe just before it goes over the shafts,his reason was to keep back pressure to maintain preformance and balance.The car now has a nice tone at crusing,but growls when you step on it.I can still add mufflers back(I may do what XKRacer has done) but I have gotten to like sounding like a big cat instead of a cute kitten.I keep all the original mufflers and piping so that I can convert it back when and it I ever sell it.

I got a new camera and was going to try to record the sounds of the new system but time got away from me with last minutes projects before winter and two weeks ago I put the car in storage till the end of April.So when spring get here I will post the video.

My advice is do something,it will put a smile on you face and if you don't like it return it to the original mufflers.

 

Eaglexkr - thanks for the input. Really good stuff. I think the easiest (and cheapest) thing for me to do is remove the cans forward of the axle, the result being what you have. Easy enough to undo if needed.

XKRacer - I will attempt to attach a zip file containing a .wav file I made from inside the car yesterday. I was pulling up a slight incline at about 2000 RPM. During the last 5 seconds or so I accelerated and you can hear how the sound I'm talking about goes away.

Thanks -

 

I think I can hear the noise you are talking about it almost sounds like a low pitch fizzing?

I think I would check to see if you have any leaks, that is what comes to mind when I listen to it

 

Thanks. I'll try to check it out next time I get it off the floor.

 

[QUOTE=XK8+XJ8L;268146]Eaglexkr - thanks for the input. Really good stuff. I think the easiest (and cheapest) thing for me to do is remove the cans forward of the axle, the result being what you have. Easy enough to undo if needed.

Larry,
It was the least expensive route I found,$70.00 for the X pipe,$75.00 new tips and $150.00 for labor and new 2.5" pipe(everything was welded in)

 

I still don't know the answer to this question. Does the existing centre muffler share exhaust from both banks or do they remain seperate through the centre muffler? Anyone know?

 

That is correct, a dual system does not work which is why you need an X or H pipe

 

So why do they merge into one centre muffler if the gases do not combine?

 

But they do combine, hence me saying 'correct' that both exhaust share the centre box, this is why you need to connect the 2 systems back together

 

What size pipe did you use, and what about that exhaust tip, is that from magnaflow or what brand..looks good.

 

OK, then in my system, with a Mina at the rear, the OEM center box and hi-flow cats, would and H or X replacement of the OEM center box really buy me much?

 

Power increase? Probably negligable. It will be louder though.

 

I do know a guy who split his centre box, took out all the baffling/sound deadening and welded it back up, made an interesting noise.

 

Good interesting or bad interesting?

 

Good interesting......made a very nice burble and not to OTT