Sorry for the delay in answering you,been doing year end planning.I used 2.5 inch pipe because thta was the size of the Magnaflow x pipe and reducers to match up with the factory pipes.I went with Magnaflow tips(35158) which were for 2.25 inch but had a reducer welded to where the factory tip was.Hope that helps.

 

I removed all the boxes in front of the axel and just have the x pipe.I ran the pipe into the factory pipe just before it goes over the axel,we did that to maintain back pressure and not have fault codes.This will give your cat plenty of roar,plus if you don't like it you can put the factory system back.Give it a try! Take a look at my photos and you can see where we removed the mufflers and replaced them with the x pipe.

 

Here I go bumping an old thread again. I want to get rid of my center muffler and add an H-pipe or an X-pipe. I went to my local muffler shop today and they told me that they couldn't make me an H-pipe, but if I provided them with one they could weld it in for me for $40 or $50.

My first question is this: Should I find another muffler shop? It seems to me that it would be pretty straightforward to weld up an H-pipe. Heck... I've never ever welded in my life, but this could be an excuse to buy an arc welder and give it a try. (I'm not totally serious, but the thought has crossed my mind. It might be kinda fun.) If a shop doesn't have the expertise to weld an H-pipe, should I trust them with my Jag?

Second, there's THIS X-pipe on Amazon that EagleXKR mentioned a few posts back. How do I know it will fit my car? It seems like there are lots of measurements that have to be just right (diameter, spacing... OK, two measurements). Would this one or this one work just as well? Both of them are a lot cheaper than the Magnaflow.

What's the diameter of the exhaust on a 4.2 liter XK8? Does the X/H-pipe have to be the same diameter, or does it need to be slightly larger to slip over the existing pipe?

I'm a complete newbie to this exhaust stuff, so someone hold my hand and tell me exactly what I need to do. My goal is to get a nicer sound on hard acceleration, while keeping the car relatively quite for normal driving. A boost in HP would be nice, too, but I know not to expect much with either an H or an X.

 

I am doing this from memory, so bare with me........ The diameter of the pipe needs to have a 54mm I/D to fit over your existing system (unless you have one of Jaguars big bore systems, add 2mm), you could use one of the X pipes you have shown but I would want to know what the sizes were first, I am sure it would not be too hard for you to climb under your XK and measure the centres of your pipes?
Making a H pipe is the easiest way, and I would not advice welding the lot together, that will give you grief in the future if you ever wanted to remove it. Go for slip joints.
A 'H' pipe will give you a different sound over an 'X' but both are good (I prefer the H).
Your local exhaust shop, do they have bending facilities? If they don't, I would look for another shop! They will struggle otherwise but you can get away with cut joints, but it is not ideal.

 

When I had my custom system done, the guy who did it couldn't remember if I wanted an H so he left both sides separate (full dual the whole way) When I told him I wanted an H, it took him less than 15 minutes to fab one up. Granted my exhaust guy is awesome, but an H isn't that hard to make. My guy was even willing to custom build an X-pipe if I wanted.

If an H is too tough for them to fab, I wouldn't want them doing any work on my car.

 

Why would you get fault codes? I drove around for a few weeks with just a 2.5" X-pipe exhaust with no mufflers that ended somewhere in the middle of the car before I completed the rest of it. No fault codes. When changing the exhaust, I ran the car with nothing attached after the cats just to hear what it sounded like, and no problems.

 

I just read this post..... Just goes to show I need to look up more before I post

Kindof answers things a bit, but you will still need to match up the CATs to it, and I am with K on this one, if they seem to struggle with the idea of a H pipe, steer clear!

 

Guys,

I have been corresponding with Jason down at Namless Performance a bit. When I told him I didn't particularly like the sorta buzzing sound I was getting after installing an x-pipe (2.25" Magnaflow, by the way), he said that I'd probably be happier by putting the center resonater back in and going with a back-half system like Mina's or the one Nameless just began marketing.

I've also been talking to a local shop that built the headers for my 'Vette (they do mandrel bending) and he said he'd like to look at that center can before reinstalling it. Said he may have something with more flow that will do the job. He wants to use that with single Magnaflows back by the tail. Since he does mandrel bending, I think I'll at least ask him about going up and over the axle with a decent pipe. Might be a slight loss there versus the under-axle configuration, but I doubt that it would be much. I'm also thinking about having him (or Jason) install the aft portion prior to removing the X-pipe, just to hear how that sounds. I've got a hunch it will be too loud for me, but we will see.

So, Sam - Sometime in the next few months I may have a 2.25" Magnaflow X-pipe you can have cheap. Guaranteed to fit.

 

I did a 2.5-inch X pipe, the shop used reducers to stock pipes...no buzzing or resonance.

 

Matt - Thanks for the info. I wonder if that could explain the difference?

EagleXKR - Do you know what size your X-pipe is?

Thanks,

 

I checked the Magnaflo web site and the X pipes are listed at $149. Any other places where they are cheeper? I thought last year I saw a thread about them being $75.
Alfred

 

Alfred -
You can find a Magnaflow on e-bay for under $90 and other brands for under $50. Less if you don't want stainless.

Cheers.

 

One of the ones further up this thread was $34 from Amazon for stainless. The fact that it is a stamped design with a small box at the intersection might actually be an advantage. The performance brand was $70 in stainless welded mandrel bends.

Amazon exercises significantly more control over their vendors than Ebay does in the event of problems with purchases.

 

Right on. In fact, I believe I got mine from Amazon and, as I recall, it was between $80 and $90 including shipping.

Cheers,

 

I had the Magna Flow X pipe (crossover) installed. I'm very pleased with its results. Very reasonable cost too.

 

EROC - Do you know what size (2", 2.25", 2.5") your X-pipe is?

Thanks.

 

This is (or should be) old news, but my local muffler shop cut out the center muffler on my XKR, and fabricated an "H" crossover for $115 - and I'm in a pretty high rent area!

The sound is heaven! My original description was that the car now sounds like it always should have sounded - from the way it looks and the way it performs! Best. DaleD

 

Guys,
I went with the 2.5" x pipe because that was what Matt went with.But according to the shop people,I could have used a 2.25". Like Matts install,they just welded on reducers.
I am still very happy with the result and can't wait till it the end of April when I can get the car out of storage.
Dale,
If I had not added the tips,my cost would have been close to yours,but I went with a nice set of Magnaflow weld on tips.

 

sorry eagle, I know the 2.5 was a bit more expensive, but being the first to try it, and document it, I didn't want to get one that was too small. Heck, maybe the 2.25 is too small, and does vibrate or resonate as Larry is experiencing, and we just were lucky??? I don't know anyone else on here that used a 2.25" other than him, so I cannot confirm that previous statement.

 

This has really kindled my curiosity. I'm toying with the idea of removing the 2.25" X-pipe and changing to an H-pipe. If I do, it will probably be in the next couple of weeks. I'll keep y'all posted.

Cheers,