Thinking about changing the exhaust on my xk8 for more power and esp. more sound at a reasonable cost. Any videos on sounds other than You Tube? Anyone remove the rears ; replace with straight pipe?
Would like to have a European sound versus the Nascar flowmaster sound......

 

Use the forum search function...there are lots of threads, pics and videos featuring many different exhaust configurations.

Good luck...I'll be working on exhaust within a few months.

 

I've heard there are harmonic problems, especially at highway speeds, with running straight pipes only in the rear. I wanted oem quad tips, which are long assemblies, so I opted for 10in glass packs reversed for relative quiet. This allowed for a straight exhaust line and made room for the tip assembly

I also replaced the air filter box for a conical air filter, which makes a great sound when the throttle opens up.

So far I've left everything else in between alone, and really enjoy the sounds the car makes. My approach probably isn't for everyone, but it worked for me.

 

I started small, as I just wanted to hear the car. Cutting out the center muffler and replacing it with an x-pipe is just what I wanted. Very mellow, but you can hear it. An h-pipe will be a bit louder, but there are others that want more, and end up removing the rear mulffer or the resonator, or both and adding something else. It gets loud then.

 

I have some concerns on adding the cone because the engine is actually picking up much more hot air.

The elimination of the center muffler sounds like a first try. Do any of these exhaust mods cause check engine light or change in fuel requirements? Where is best place to get "X" pipe and pricing? Anyone have the size needed?

 

I did exactly what you said you didn't want: https://www.jaguarforums.com/forum/x...ter-40s-37811/

You could do something similar and just switch up the mufflers for a different sound. You are never going to get a truly Euro sound out of these V8s as they are, like most American V8s a Cross Plane Crank design rather than the Flat Plane style that Ferrari, Lotus, TVR, and many race V8s utilize. There will always be a bit of a burble rather than the sort of twin I4 style concert.

Rather than fight this tendency, I enhanced it with a chambered Flowmaster muffler. It's got a nice burble. I'm not sure what sort of muffler would be needed to fight this.

Also, to get a dramatically different sound would require different manifolds and that certainly isn't cheap or easy with our space constraints. You could switch out the catalysts for nameless performance high flow units, which would help performance more than a simple exhaust system and would also make the exhaust note louder, but they might be more than you want to spend.

 

Another idea is to cut out he middle mufflers, and replace them with an X pipe (obtainable online) from the big muffler manufacturers direct.

Then, get rid of the elbows over the rear axle--the most restrictive "pinched" tubing you've ever seen. Keep the rear mufflers.

Too bad the strangely shaped catalytic converters are so expensive--to replace with more streamlined, less restrictive converters. They're down the wish list as long as they meet emissions standards.

 

I just listened to your videos and liked them! The sound may be a little loud on hard acceleration, but seems to bring a smile to my face.

I think the chambered muffler is the route to go;remove center, replace w / x or h and a smaller chambered muffler on both sides/ twin tip. Only a guess from looking at my Maseratis exhaust system (Tubi ) . My old cars always had an ANSA twin tip or Tubi type system and always had the right sound and never too loud. Maybe someone at Borla or ? could answer the sound question. These guys test every configuration possible prior to releasing their sets.

 

I cut out the center and added an H pipe to both of mine. My XK8 doesn't sound so bad, but on my XKR it sounded horrible.

I would avoid cutting out the center muffler unless all you want is more sound and don't drive aggressively. It adds much more cabin noise and exhaust volume is not consistent over the RPM range so it gets louder and quieter depending on what RPM you're at and if you hard accelerate through a couple of gears it sounds pretty bad, IMO.

So I decided to replace my whole exhaust. I added NP cats, a Borla center muffler and the Mina exhaust and now it sounds absolutely amazing.

BTW, the factory cats suck up more of the exhaust note than the actual stock mufflers themselves. After replacing the factory cats with the NP, it was about twice as loud.

 

I also installed the Nameless Performance cats on my 2005 XKR Coupe and they have been excllent. The quality and price of the NP cats make them a real value purchase. I will likely add the Mina exhaust in the next month or so.

 

These posts bring up the question of cat replacement. It seems that power loss occurs w/older cats from blockages and tone loss. Might not be bad idea to start w/cat ( high flow) replacement BEFORE any exhaust changes are made. See what power /tone changes are made.

I assume that from reading posts that cat replacement w/high flow system does not activate any codes. Is this correct?

Be great to see some before /after runs on a dynometer just toying with the cats.

 

Yes, I would suggest replacing the cats before doing any other exhaust mods, except for maybe replacing the restricted over-axle tubing.

The cats do not cause any issues. It does not throw out any codes.

 

I did not see what year you had but check out Nameless Performance.
jaguarforums.com/forum/showthread.php?t=42641

 

I have had the lower-restriction cats on my wish list for a while. My hesitations are (in order of importance): (1) the exhaust sound will increase more than I want (2) a bit pricey by the time you buy the pieces and do the install (3) never really seen any definitive measurements to show what you will achieve by doing this (i.e., bang-for-the-buck factor).

Doug

 

What's the solution to the restrictive elbow over the rear axles? Run the pipe underneath? Is the remaining clearance adequate?

 

I have had the over axle pipes replaced with straight pipe,and was initially concerned that the pipe under the axle was too low (mine is actually lower than photos I have seen).
one year on, and there is yet to be any sort of scrape or contact with any surface below the car, so it seems that my reservations were unfounded.
I have the Nameless Cats, and have removed the intermediate mufflers, between the large central muffler, and the 2 rear ones. Not too loud, but nice growly tone. May remove central muffler and replace with X or H someday.

 

Adamesh do over axel pipes (LOOK HERE), I have fitted them a couple of times with no issues


Must admit I am a bit tempted by the Nameless cats, they do look a nice well made item

 

2002 XJ8

It is not any louder in the cabin, and now you can hear a little lower tone from the rear while standing behind it. Very subtle, but noticeably improved, and the butt-dyno likes it too.

Probably less than a 5 hp gain, but I would do it again.

everything else is stock for now. I may change the mufflers in a few weeks if I want to take another step in this direction...

 

Hey newby, welcome to the center-box-delete crowd! I had an urge awhile back, thinking I wanted it louder, but after a year, I am really glad I didn't do anything else to mine. I'd recommend driving it for a bit, let family and friends give their opinion if they like how it sounds (only mention it in passing w/o making a big deal about it) and then you'll be able to answer your own doubts about more mods down the road.

 

Does the XJ8 have more soundproofing than an XK? I would think by the nature of the vehicle it might. If you're a lead foot, you probably would notice more cabin noise. I did notice quite a gain on both of mine.