I spent over two hours going through all of the threads on modifying/changing out the exhaust system on XK8's and XKR's. Listened to all of the YouTube videos also, and came to the conclusion that it is so subjective that there will never ever be a clear consensus. Even videos showing the same muffler delete were very different depending on how they were recorded.

I'm looking for a moderate increase in sound that lets me know there's a V8 under the hood, but not something that sounds like a big block with open pipes. Have gotten down to two scenarios; rear muffler delete or replacing the rear resonators with Flowmaster 40's or 50's. Haven't found any audio tracks for the latter, and was wondering if anyone out there went that route and what the results were.

This will the last time I bring up this topic, I promise!

Max

 

I have Flowmasters and subtle, they are not. I love the sound of my 40s, but in hindsight, probably would have gone with 50s.

Here is my writeup (surprised your search didn't uncover it, or maybe it did, but you mention not hearing any examples)
https://www.jaguarforums.com/forum/x...ter-40s-37811/

 

Yes, very subjective...lots of opinions as you found. It is so difficult to know where to start. First I had the center muffler replaced with an X pipe, barely noticable difference, but some, just not what I hoped for. In my opinion, not worth the effort or money as a first step, but maybe a later option to eek out just a little more sound after other things are done and you want just a bit more. Then, Rear mufflers removed and straight pipes with factory tips installed, but this was too loud for me, sounded great at idle, but just overall too loud and way too much drone. I added magnaflow glasspacks, which cut overall noise, and reduced drone, but there still was a more drone than what I could live with. So I had J-pipes made up for each side, and this turned out fantastic. The J-pipes completely eliminated the drone, and left the beautiful sound to hear. Very subtle really yet sweet v8 mellow sound.

 

I found all of your videos, including the one you mention above, but I wasn't sure how much of what I heard was due to your removal of the center muffler, and how much was the Flowmasters. I'm trying to get a little bit more of a low burble at idle, and additional volume when I get on it, but not an absolute roar. Interestingly enough, the sound on the videos with the rear muffler delete varied a good deal more than you might think, which is what has me on the fence.

 

You bring up a good point, which is, people seem to have different results when seemingly doing the same thing. I have wondered something for a while now. Even though the ehaust system appear the same through all the years, I wonder if Jaguar modified the muffler boxes for different years. For example, the center muffler probably is the same, but the 2 before the axle maybe had a lot of noise suppression in early years and the rear most boxes maybe minimal noise suppression, but later years maybe Jaguar revered that? Idk.

One thing that you may not have come across: apparently changing out just the catalytic converters to 400 or 200 cell makes a huge difference. If I ever had to do it agai, I probably would do that first. I spent at least as much $ doing all I did as it would have been if I just did the cats.

 

I removed the two before axle boxes and added a K&N air intake. while I often wish for a tad more sound I think it is just right. Very soft rumble at idle and barely noticeable at speed but between the intake roar and the exhaust when I punch it the sound is great.

 

According to a Motor Trend survey, the median age was in the mid-50's. The average new selling price was $72,000. Perhaps those new owners didn't want a loud, noisy car and those that did, purchased a XKR. As the cost of a used XK8 is now in the high four figures, a younger age group can now afford one and want a little more exhaust note. I know what kind of sound I wanted in my 20's in a car and what I want now is completely different.

 

So no change in tuning? Performance remains set properly without remapping?

 

Thanks for the tip Steve; hadn't considered changing out the cats. Already have the Mina air intake; nice sound when you get on it. Now if I can just find the magic combination/holy grail for the exhaust system, I can drive with a smile on my face without incurring the disapproval of my other half, or the wrath of my neighbors.

 

Any chance you can post video or sound clip?


SteveJacks, I'd also like to hear yours with the J-Pipes, if possible.

 

"So I had J-pipes made up for each side, and this turned out fantastic. The J-pipes completely eliminated the drone, and left the beautiful sound to hear."


What are J-pipes?


Thanks!

 

I've heard the term "J" pipes before, and I believe I even saw a picture somewhere, but in what way are they different from the other exhaust configurations discussed in this thread?

 

As I understand it, J pipes are additional pipes welded onto each exhaust, but do not exhaust anything. In fact they are capped off.

They are out of the exhaust stream and only meant to reduce the "drone". Sound goes in, is bounced off the cap and routed back into the exhaust. As it is now "opposite" of the regular sound waves, it eliminates the drone. no effect on performance plus or minus.

Many engineers on this forum. Someone will explain it better I suspect, but this is the lay person version. Check out some of the rice racer sites and you'll see lots of comments on this.

 

Found the answer (thank you Google). A "J" pipe is essentially a Helmhotz resonator used to eliminate drone in your exhaust system. It's of a specific length for the car/system, and provides sound at a frequency that cancels out drone. They're welded on to the existing exhaust pipe near the rear resonator, and the open end plugged. They don't impact exhaust flow, but are there to mitigate unwanted sound frequencies in the system. There are formulas to decide diameter, length, etc., but at that point my eyes glazed over.....

 

Hi Max, all I can say is, I am happy with the rear muffler delete by Mina, Boarla exhaust tips and the K& N cold air induction filter for my '99 XK8.
Exhaust note is present, more so when you step into it. Not loud at all. Pleasent with heavy go-go pedal.

In addition, I can also say I did have changes to the tones after the computer adjusted itself to all the fresh in/ out air. Did take a couple hundred miles though.

Lots of luck with your decison
Rich

 

Correct, thank you, you beat me to it...I think some of the early XK8/R's have a similar version of this on the plastic intake pipe; if I recall correctly based on some photos I have seen. I knew of the concept of the Helmhotz resonator but had not considered it for such an application. My exhaust guy said he does it a lot, but few exhaust customizers know how to do it, or even know of it. Also correct that there is a way to calculate the length of the j-pipe and I think it is based in part on the frequency of the drone, however, my exhaust guy is no mathematician...I think it comes down to trial and error and experience, maybe a bit of luck. Not putting him down at all, but is there really a need to determine the resonance frequency, then do the math? I think it would it be less time consuming just to build it, and adjust as needed. It's easy to adjust the length to tune it if needed. I will pull a rear wheel in a few days when I have time and take a photo and do some measurements. Frankly I was surprised at how effective this was, and how clear the "nice sound" is now. The exhaust guy told me that in his experience, the j-pipe does also tend to reduce overall volume a little as well, and he thought that if I thought the straight pipes out the back was too loud before the j-pipes, I may really like it with them, as the sound won't drone of course, but the volume will be less, and it will be more mellow than it was.

 

Here is a photo of one side of the exhaust J -pipe.

 

That is interesting...and yes, similar to the intake silencers. You should post a video of the sound!

 

I will give it a try, but typically the video clips I have seen and heard don't really provide the real experience as it would be heard while actually being there in person, particularly when made on the phone as phones just don't have good fidelity, and can often enhance other sounds like wind noise etc. I will git it a try though.

 

I find the videos never to be a good indication of actual sound. I can tell you removing either the center resonator or rear mufflers will give you a sound increase that isn't awfully loud. I had my resonator removed first.....Wasn't quite loud enough. Then did the rear muffler removal and now its loud. But people like it. Worst case you add some high flow mufflers to quiet it down after that and you'd be good to go. My next move is removing that two mini resonators and the crunched piped and adding two rear mufflers to quiet it down. I can only assume no mufflers would be WAY TO LOUD!