i'm doing the resonator delete and adding an X-pipe in tmrw am. I assume that the best place to install the X-pipe is where the 2nd resonator is (closest one to the rear axle), or is there a more affective spot in between the 2 resonators? Thanks for any input.

 

Put it where Jaguar did.





And make sure you get the right size

 

+1

 

tnx cambo. yeah, that makes the most sense, and yeah....I got a 2.25" X-pipe, which is exactly what the stock pipe came in at. I also got the X that had the least gap between the pipes (all were wider apart than the stock pipes), to make it a cleaner job.

 

Maybe it is a year or model difference, but my stock exhaust is all at exactly 60mm.

 

that's odd, because when we get the mic around it at the exhaust shop last week, it read exactly 2.25".

 

I don't know what to tell ya. Mine's never had any work done to it except the resonator delete, and I watched the whole thing. The entire system - 60mm.

 

I like putting them up close to the engine as I figure hotter gases have more energy and closer is a sharper pulse to draw the exhaust from the opposite bank. I'm pretty sure Jaguar did it where they did to sound different.

 

Old-timey hot rodders (like me) used to put a mist of white paint on the exhaust pipes, and where it turned the brownest was 'supposedly' the best place for an (at the time) H-pipe. Reasoning would suggest that using the old wisdom that an X-pipe would also be in that location.
Is any of this accurate? Hell, I dunno.

 

The ideal location is going to change based on pressure wave location and length in the exhaust system; and this is going to be variable based on exhaust velocity and pressure, which is in turn variable by engine RPM and load.

You can also run two X-pipes if you wish.

 

Well the factory XKR-S exhaust design "works" and i'd say Jaguar had a bigger R&D budget for this than we do...

 

Yep, but their R&D also decided to put brittle coolant lines underneath a supercharger.

 

OK so I just went out to measure my exhaust pipes. Now I have a 2012 XKR convert with the $1400 performance active exhaust option. Stock system. I measured the down pipe after the cats and it was 2.368 ". Note as it goes into the main pipes it necks down. The OD of the pipes from here into the X-pipe and back into the back box (muffler) is 2.175 ". Pipes look new yet and they are round so these measurement were as close as I could get it. Just an FYI

 

Thanks for the measurements!

 

I just had this done on Friday. I had them install it in the factory XKR-S location.

it sounds great! Not too loud at all. I used a 2.25” X-pipe.

2012 XKR.

Joe

 

Based on the measurements I had taken it shouldn't be a problem welding in a 2.25 OD pipe. My bet is the pipe on the cat's are 60 mm reduced down to 55 mm. So a 2.25 pipe would be about 57 mm . The gap shouldn't be a problem welding shut.

 

yep, you nailed it.

 

 

Jaguar's design is likely influenced by the need to still be a GT as opposed to a brutal visceral sports car. All exhausts systems for a street car are a compromise of some sort.

When it comes to OEM, production and assembly methods create costs that also factor in to that compromise. On top of that there is design time, also a cost. Spending extra on each component delays release, costing in both engineering time, and lack of production/sales with the new design.

 

It's kind of funny. On my old Lincoln LS with the Jag 3.9 AJ from the factory they combined the mid pipes in the form of an X pipe under the trans by hydro forming two sheets of stainless, only they didn't connect the pipes. Further back where Cambo's pipes have the X, it had a 3/4 main diameter 'H' connector and then a pair of X100 style mufflers tucked up behind the wheel well.

When I redid that pipe I did a 2/3 port opening X pipe (like I did in my build thread) and ran the rest of the way back with 2.5" pipe and finally a pair of Pypes turbo style mufflers. That car sounds ballsy for a little 3.9 NA engine. I wanted more of an old school E type sound so I went with glass pack style mufflers at the bumper and smaller 2.25" pipe feeding them. It has a very distinct sound as well.