Again I'm finally tinkering some more with our 75 LS1 powered XJ6C, a project I should have been done with long ago, but other projects seem to sneak ahead of it. Although it's been driveable for years, I probably have put a grand total of maybe 100 miles on it in the last 4-5 years and not before that (the car has actually been in the shop here since 2007- yikes). Not to say it was a waste of time- we learned a lot from that build that went into many other projects that actually did get finished, and enjoyed. Well, it's been sitting up on the lift for a long while and one the other things I constantly stare at is the exhaust system. Long ago I got frustrated with exhaust shops that would listen to what I wanted, say yes, shoo me away, and go to work on my car. Nearly every time the end result was not what we talked about or poorly done, or both. Once I had an XJS brought back here after an exhaust build and the steering wouldn't turn- the steering shaft was hitting the headpipe they just put in.. So I resolved to try may hand on it myself, and see what happened. This car was the first candidate (victim?) but it didn't come out badly. I fabbed custom 2 1/2" headpipes from the LS exhaust manifolds down to floor pan level and then ran a 2 1/2" mandrel bent dual system all the way back, under the center of the diff, and then out to the stock locations. I was able to squeeze common size turbo mufflers ahead of the rear axle (did you know that on XJS and XJ6 models Jaguar used an non-standard size turbo style muffler there, a size you can't get in a 2 1/4" or 2 1/2" size???). Anyway it all went together and for a first try not bad. Not too noisy, good fit, no rattles, so overall not bad.

However, in the years since, we have done all of the prototype systems here in house and they have got better and better. Also, Flowmaster offers a 2 1/2" mandrel bent exhaust kit- a selection of different smooth bent sections to be put together for a full system- and it works great for these applications. And on the later cars I was using a stamped X-pipe crossover that not only is great for power also did plenty for canceling out noise. Now, 8 years after doing that first system I was looking up at it on the lift and it looked a little scruffy- not up to spec any more. Since the exhaust recently came out for the outboard disc rear suspension upgrade, this seemed like a good time to get in and do a proper system. We also now have an exhaust pipe expanding tool in house that makes putting the sections together and adjusting them exactly the way you want easy. Below are some pics of the original system and then the new system in and out of the car. The original headpipes were retained but everything else is new. The new system is 2 1/2" pipe, all mandrel bent, using a center X-pipe crossover, and going to 2 full size turbo mufflers ahead of the suspension. From there the pipes go tightly under the diff and then left or right to the stock exits. On this one I included 2 small glass packed resonators in the rear muffler locations in case it was too loud (they can easily be removed if it's too quiet). The muffler tips are maybe a little too Batman for this car but I had them sitting on a shelf looking for a home.

Have a look at the pics and should you have any questions, let me know

Andrew
Jaguar Specialties




This is the original 2 1/2" custom exhaust before it came back out of the car . The loose clamps there in front of the view were used to attach the tail pipes-not shown- to the main section


Main section of the new system- very simple and all bends very smooth





New system up in the car looking from front to rear


Again looking front to rear but here you can see how it passes under the diff. It is rubber mounted to the front of the diff cage lower front rail



Another view looking rearward. You can see the mufflers just fit the space- there is less than 3/4" clearance between the fronts of the muffler cases and the silver jaguar heat shield there



And the tips, coming from the stock exits. Not sure if these will stay, but for now they're ok....

 

Looks great to me! Nice job.

Agreed that the tips are bit too "Batman"

Are you concerned about lack of ground clearance beneath the tailpipes?

Cheers
DD

 

Actually, the picture is a little deceiving-there's more clearance than it appears. Initially when I first started doing it this way I was a little concerned too for speed bumps and all that, but this is the lowest point and it's right between the rear wheels so as they go up and over, so does the exhaust. I suppose a perfectly placed tall narrow obstacle could be a problem, but these cars are so low anyway that another point would likely hit first. So it's a trade off. I try more to protect the engine/oil pan, etc.,. and now worry less about the exhaust. And in all these years since it hasn't been a problem....

See the attached pics- these are a few other of Jags that used this format as well- seems to have worked well...



99 Vanden Plas with 2002 LS1

98 XK8 with 2002 LS1

88 XJS-C with LS1; you can see here that the center pipes under the diff are only fractionally lower than the bottom of the the suspension hubs outboard there. So we're not really losing much. Note- that center structure is part of the undercar support added on these T-top models. I had to go around that.... (tail pipes were still to come at the time of this pic)

 

Andrew, the last picture... Tell me about that brace under the IRS???

Can you get more pics of these?

 

So the bracing you see there is something that was added by the factory when regular coupe XJS cars were converted to XJS-C's. It bolts into the bottom of the trunk floor forward, under, but not touching the rear suspension, and bolts into the trans tunnel a foot or so ahead of the diff. It's called the "cruciform" and is made of the some 1"x1/2" steel tubing. The part number is CAC 7196. If you decide you want one, let me know as one of my suppliers has several of these cars in house...

Pic below- the section with the diagonal brace goes forward

Andrew