I think what philhef has done is probably the way to go, after reading alot obout exhausts over the last few days im inclined to think the "H pipe" is the best option maybe with some new rear mufflers.

would like to hear it and see a picture from underneath philhef

 

Ok if you want my personal opinion and I know very little about performance and such, just what I like to hear, here it is.
If she wants a little more sound but not aggressive like the F Type, I'd say my very first and cheapest thing I did is it. I had the center muffler removed and straight pipes put in. That's it! It was a bit louder, and deeper but most of my friends expecting a roar were disappointed but personally, I liked it the best. No droan at all, no spitting sound on high rpm like F type, but just loud enough to make me happy. It's a cheap job, and cheap to put back on if unhappy.
Truth be told, I'm keeping my small mufflers just in case I find I tire of the new sound. Although I'm getting used to it now. At least I'm not getting any droan like It had at its worst configuration.

 

Honestly that's probably more accurate than the F type. All I can say is the droan I had at its worst was with the small mufflers still there. So I'm not sire about them keeping it down.
Like I said, I have a new H pipe in middle and rear factory mufflers re installed and I'm pretty happy. Regular driving sounds rich and noticeable in a good way, flooring it I get the spit and snarling I wanted as well. I'm working on getting a good video as soon as I get time. Heading for a trade show for a couple weeks then off to the JCnA Little Switzerland Concours show to see if my XK8 has the stuff!!

 

Before I get to the exhaust, Ill explain where most of us are missing stock power.
1. Premium octane fuel is not being used,the knock sensors will detect this and retard timing.
2.Old oxygen sensors are metering air, but very slowly.The computer compensates and this robs a ton of power and creates bad gas mileage.
3.You have a fuel filter under the car, no one has ever bothered to change,this takes away power in the mid and upper where you need it most.
4.You have spark plug galleries full of oil,the oil will heat up and create vapors of oily liquid, that will cause misfires.
5.MIS-ADJUSTMENT OF THE THROTTLE CABLE. Most are adjusting to remove slack WRONG,adjust until you can barely tap the gas pedal and the engine revs up immediately.
6.Tire pressures are set to the factory 26psi. This creates a drag! Try riding your bike with low tire pressure and see how hard you have to work to get going and stay going. 35-40psi is where its at,also consider rolling resistance tires.

7.You have a worn engine that needs to be replaced or you buying a new car.If your engine is ticking knocking any noise thats internal beside the timing tensioners, its time for another car,unless you are full pledged in keeping the one you have.


Now the exhaust

The factory exhaust was tuned to make immediate power from idle to the mid range, in conjunction with transmission shift points. The 4.0 is a small displacement high revving engine with DOHC heads.

The drone comes from the exhaust turbulence.

To combat the drone, the exhaust must be equally balanced,meaning if you cut something off, something of similar restriction must be applied to maintain the proper power to noise balance to a point where you gain performance without too much noise.

2. Since the engine is exhaling better, it needs to inhale better. Simply remove the air silencer off the factory airbox and install a K & N air filter.

3. The pipes almost crush flat over the rear axle is the most restrictive point of the exhaust.


4.It's a gain worth every penny you spend. With me personally seeing a XK8 pull 309 HP and 318 Ft lbs of torque without the tune at the engine in proper running shape.

 

Continuing to make notes, letting you guys be the guinea pigs. Has Phil now or Westra long ago nailed it? I'm planning to put the best practice in place closer to year-end.

I'm still interested in going the under-axle route to clear the factory restriction, but I'm not sure anyone's done this yet.

 

Like I said, if I were to know how each piece would sound as removed, I would have probably stuck with my first try. Just remove the large center resonator. It sounded a bit louder but didn't sound out of place.
Right now I'm still getting used to the sound with the center H pipe, second small mufflers removed and factory rear mufflers replaced. Regular driving and even sport mode sound great and I've yet to notice any droan. The only time I question is if I really hit the gas, pedal to the floor. It gets the raspy spitting back note. Now I know that's the sound some are going for and it does sound like youtube videos of the XKR S so maybe I've got it right for not buying $$ boxes. And it does turn heads. So what am I wondering about!! Lol (oh and I've noticed a touch better gas mileage! Now that I've stopped flooring it to hear the sound!!)

My only advice is keep all the factory parts that are removed. It's easy to go back as long as you have the parts!!

 

Im with you sentinelist haha. Am almost certain to go for the h pipe as close to the front as possible and if thats not loud enough maybe change the rear mufflers. Got mine booked into a custom exhaust specialist to get it in the air and have a look at what they can do.

 

I'm ordering a K & N filter as we speak!!

 

If you want a burble on idle and acceleration but no drone This is what I have done and am please with the results. Granted way more expensive than just pipes.

I have Nameless low flowcats, jag factory center pipe, mini under axle mufflers.

1997-2000 Jaguar XK8/European XKR Downpipes - Nameless Performance

Performance Exhaust Mina Gallery for Jaguar XKR

If I can figure out my tablet to post a sound clip I will. But this clip is pretty close to what I have. Maybe not as deep.

I believe this car is a forum member just can't remember their name.

nameless performance jaguar you tube - Bing Videos

 

My 2 cents worth after reading all the posts and if I were starting again is that I would leave the center muffler alone. It works exactly as an H-pipe allowing both sides of the engines exhaust pressure and sound to crossover and adds no resistance as it is straight through design and muffles the sound slightly. Remove the mini before axle mufflers(which is what "Philhef" ended up with, and is so pleased) and at the same time replace the restrictive part of the over axle pipe(first half of the over axle pipe) and leave the back mufflers. my muffler shop would charge $105. Has someone tried this exact config. Let all of us know, Please.

 

Well i was going to get a h pipe BUT the exhaust place wants £300. i think ill keep my £300 thanks

 

I can tell you for sure that even though they may act the same they definately do not sound the same. I had both and the H pipe definately has a different sound.
And my muffler shop made my H pipe for about 30.00.

 

I'm going to try the mid muffler delete soon, I'll get a quote for that in the next couple of weeks, seems like UK exhaust shops are 10x the cost of US ones though.

 

My shop is a local independent. He charged me 80.00 to remove the center and first put in straight pipes, then another 50 to make and install the H pipe. That's how I know the H and the factory resonator sound different. Resonator is quieter, straight is louder but uneven, simple H keeps loudness but smooths out. Loosing the two small mufflers will boost sound, give an F type spitting at fast take off, and quiet down at cruising speeds. I noticed no droan on the long drive to the Concours show last weekend.
Almost every XK8 owner asked what I did to my exhaust and most were booking theirs for same change!! Lol. I did add Mina large oval tips to factory rear mufflers.

 

I like what philhef has done except, i would not touch the center muffler, I installed an x-pipe and it is just slightly louder. The center muffler is an H pipe that muffles the sound a little, It will be a little quieter than an H pipe( it does have muffler like characteristics). It is a straight through design though(referencing photos in my original post). Save your money, leave the center muffler (it is well built and weighs less than 20 pounds) and eliminate the before axle mufflers. It should sound like philhefs but a little quieter which is what I initially wanted. You can either go straight from the center muffler(factory H pipe) under the the axle to factory rears or my muffler guy would have went from center muffler to factory rears and customize proper over axle pipes for not much more than the x-pipe install. There has been a lot of great input on this thread. and everything I have said is only my opinion.

 

Question for Philhef. I am seriously considering trashing my before axle mufflers. My center muffler when it was removed had the flanges cut off almost flat so it is not going back on (So I can not compare sound with just before axle mufflers only being removed). I was wondering in your opinion of course, if you think the sound will be similar to yours but with an X-pipe to factory rear mufflers instead. The center muffler delete to an x-pipe (although sounds good) is just a little bit louder than stock. Your opinion is valuable because you seem to have figured out the exhaust combination question with out spending alot of money.

 

"Simply remove the air silencer off the factory airbox" Anyone have a picture of this. I'm not sure if I fully understand what the air silencer is? And anyone have the K&N filter model number?

 

When I bought my 2001 xkr I was mortified when I looked at the factory exhaust. Moreso than on my 2004 xjr which is light years better IMO yet still pretty awfull. The center muffler had been removed prior to my purchase and it had just a slight burble which didnt get much louder upon heavy pedal mashing. Well I saw the Mina muffler delete pipes on sale and said WTH. WELL...The jag is now obnoxiously loud. I do kind of like it however. Ill take a clip this weekend. People say it sounds great but a bit to loud for my taste

In teh future I do plan on getting an x resonator from dynomax and removing the before diff mufflers and keeping it at that. Should reduce volume a bit and smooth out the tone. Ive had great success on other cars with the dynomax ultraX resonator I suggest you give it a try if removing some of those other mufflers:O). If I ever want to spend some good money on the exhaust however Ill just go full 2.5 inch with high flow cats. But for now I have bigger fish to fry with this car. I have the part number I purchased for my xjr. Ill post it here when I get home. Its huge.

 

This is my K&N on mine



It was like this when I bought it yesterday. I still have the stock airbox as well.

 

Well I'm taking the plunge for an exhaust mod. Going in Thursday to have something done, to be honest I'm not sure what. Have read everything I can and listened to so may sound clips I'm sick of them. Very confusing as I'm on a budget and experimenting can get expensive. Shop labor is very expensive on Maui.

I DO NOT want a loud system, just enough growl at idle to hear it and enough noise when manually shifting thru the twisties to hear the exhaust. Also want a nice but refined "get out of my way noise" when I hit the gas hard.

So here's my plan of action:

Option 1
First remove the center muffler and replace with an H, straight pipes into stock before axle boxes. See how it sounds and go from there with possible removal of the before axle boxes.

Or

Option 2
Remove the before axle boxes, see how I like it and possibly remove the center muffler and replace with an H.

Can't decide with to remove first the center or before axle mufflers.