Hello Community,

Thanxs to some members on this forum, I have managed to get some very useful information in order to do exhaust modification I am looking for.

Basically, I am looking in doing this mod : https://www.jaguarforums.com/forum/x...-149357/page3/

However, I didnt manage to get the technical information that I need...

Does anybody (who has done this) know or have kept the info in their records in order to do it properly (pipe size, pipe length, x pipe used (custom or pre-made), angle on bended pipes, etc....

Thanxs in advance

 

Are you going to do the work or have some workshop do it?

 

Hi Daim, not sure yet If I can find a workshop close to where I live...If I have all the info, I might try with some friends

 

I'm the only person to have done this so I needed to gather all the measurements myself.

1st off: my 3.2l V8 has smaller pipes. So you need to get onnyour hands and knees and measure the pipes around the cats, arount the center bis and before and after the rear mufflers.

2nd: you won't need any more than about 1.5m of straight piping. The rest is used fromt the exhaust itself.

3rd: the X pipe needs to be the width as the two pipes entering and exiting the middle muffler.

So, even if you had my measurements,they wiuldn't help you. Also, the connectors between cats and muffler cannvary. Fixed, flexible, dished.

I'd really recommend you to get it on a lift first and then measure up to determin what you need. And you will want the X as far as possible to the front of the car. Problem is, the tranny is in the way, so it has to sit as far forwards as the center muffler.

My X pipe was custom made, as you can't buy any in the size you need...

 

Ok, so for instance these wouldnt do the job ?

MAGNAFLOW 10790 EXHAUST 2.25" UNIVERSAL X-PIPE CROSSOVER PIPE STAINLESS STEEL | eBay

MagnaFlow Tru-X Stainless Steel Crossover Pipe 2.5" 10791 | eBay

As a matter of interest, how come the X should be as far as possible to the front of the car ?

Additionnaly, a flexible connector is to avoid having to bend regular pipe, right ?

Cheers

 

Again, check your car first. Mine didn't have flexible connectors. They are made to allow for some motion of the exhaust vs engine (the exhaust is more stiff like the body rather than movable.

The X has to sit as close as possible to the front for the exhaust gases tomflow at a higher velocity and tomcross quicker. That also aids to prevent sound deadening (what you want) but also droning. Those universal X pipes only work on US cars, as the Jag setup is different. You need some very smooth, less angular curves to make the X. No 90° pipes. You want narrow, parallel pipes (see the pictures of my boot/trunk as in the tread you posted, as there is how my X pipe looked like), with a very large radius bend used to form the X as such.

 

Ok very interesting thanxs. Now let me ask you another quetion please. Imagine I want to take it in two steps...before doing the whole X thing. What would happen if I only removed the mufflers before the axle and replaced them by straight pipes, would that add growl to the car (considering I already have the mina after axle setup) ?

 

That will add a good bit of growl. Might be enough for you.

 

ahahha....it's never enough, but on another hand I am looking for something simple and easy to remove for inspections. Anyways, you have been tremendously helpful and I really appreciate it...thanxs

I think I am going to start with that first mod and see / hear what happens. Your advice regarding the X kind of got me thinking...

 

I just did this on my xj8 and can tell you, unless you have a pipe bending machine, it's next to impossible to do this.

After the car was on the lift, I told him to remove the resonator and center mufflers and
join to the pipe just before it goes over the rear axle.

From the cats to the center muffler is a straight shot. Since your removing the center mufflers, the pipes must be bent custom to compensate for the removal of the mufflers. The center mufflers are not parallel to the ground. They go UP into a cavity just before the rear axle. That is how they hide them so they don't hang too low under the rest seat floor pan. There is no stock pipe for this unless you want to start messing with 3 or 4 elbows.

The pipes go from just behind the cats straight into the stock mufflers and it is considerably louder.

I have magna flow cherry bomb tube mufflers coming in next week to finish off the job.

One big thing I ve noticed: my gas Mileage is going UP despite the fact I'm really putting my foot into it to hear my car roar. I've had this modification for a week now and my average mpg has gone up 2mi per gallon.

 

Hi Rpach,

Thanxs for your input...

Just to be sure I understand, you have 2 straight lines frome the cats, but where do they join ? did you do an X or H connection between them at some point ?

Regarding the cherry bomb tube mufflers you are getting next week, where will they be placed exactly, instead of the center mufflers / resanotars before the axle ? By the way, what is the adavantage of having them fitted ? better grumble, lower mpg, anything else ?

I would rally appreciate if you could upload a few pics

Cheers

 

When the car goes in this weekend to have the mufflers installed, I'll take pictures when it's up on the lift.

 

Any chance you could get them to cut the old centre muffler/H pipe open so we can see inside?
I understand it's probably a pain for them, and they'll just want to bin it and move on

 

Sorry, that was removed last week. It's already shredded.
I removed everything from after the cats to the stock rear tailpipe mufflers.

When the new magna flow cherry bombs come in, they will be installed. They will replace the tailpipe mufflers..

 

Someone on here a while back posted an autopsy of all the x308 mufflers, don't remember who but it's worth searching around a bit for it. Had lots of detailed pictures and descriptions.

 

Good I save each and every picture which I think might be of help for me sooner or later .

 

Awesome, thanks all! I must have missed those

Kinda confirms what was suspected all along, there is very little restriction from the centre muffler as far as flow, more just for sound

 

Great thanxs...looking forward :-)

 

I did this also. I replaced the center muffler with an x-Pipe. and ran iit back. I didn't notice much difference.
I ended up taking it back off for no reason. It's still sitting at shop so I'll get pics in next day if needed.
I also cut open the exhaust and posted pics. Probably somewhere in post history but similar to above.

 

How about Magnaflow (#10790, 2.25" X pipe and replace large Center muffler? OR, install X ahead of large center muffler, remove the "over axle" L and R mufflers? (Are these considered "Resonators," or final pair before tilps?) Seeking some "rumble" and exhaust gas flow-hp improvement. Thanx !