On a stock XK muffler is there a external flap you can mechanically keep it open or is it buried in the muffler it self?
I understand the XKs flap is pure mechanical that opens on exhaust pressure right?

Thanks!

 

It is a spring loaded valve unit that is external but, tack-welded to the sides of the large muffler. You can readily see it when you look under the car. You are correct, it is exhaust pressure operated.

Albert

 

correct me if i am wrong, but this is only on the "R", no?

 

I believe the XKR is electrically operated valves and call be left open by pulling a fuse.
Is there a way to keep the "XK"s flap open all the time?

 

No, not that I know. If you want to experiment, you could grind off the spot welds from the spring units and see if they pull out of the muffler. Then, you would have to put something in its place.

Albert

 

In the last month or so I have run across a few 07/09 XKR exhaust mufflers for sale. This seems like an easy way to get the Quad XJR look and perhaps a performance boost.

The problem is that the XJR mufflers have an electronically activated bypass while the XKs are back pressure activated. So you end up with a muffler system on your XK with no bypass capability at all. I presume the Xks do not have the necessary circuits installed

Do you guys read it the same way?

 

The XKs likely do not have the wiring and circuitry to operate the XKR muffler valves. However, you've just provided an idea for people interested in a bypass muffler; get the XKR muffler and simply install a dash operated switch to open and close the electric valves. Should actually be a very simple installation.

Albert

 

Yes great idea! What have you been seeing these used ones going for?
And where have you seen them forsale?

 

Go look for a adjustable barometric switch on ebay, tee into a vacuum source as a sensor then use the switch to control a relay to kick in a low vacuum. All in cost should be $30 or so.

If you want to go cheaper, you can do it with a pop bottle, some hose, a stick, some wire, thumbtacks, a relay and some water. But, it gets a mite messy.

 

There is at least 1 on the "for Sale BY Owner' forum. Also there were a few 07 and up XKs being parted out there too - as well as EBay.

 

Saw this on eBay ...kinda interesting and could work if it dumped out to a muffler tip next to the stock one now giving you quad tips...

http://www.ebay.com/itm/JAGUAR-XK8-2...sories&vxp=mtr

 

I put some on my XJR, WOW! https://www.jaguarforums.com/forum/x...ll-pics-72079/
Vector