I wonder if any of the Members with a lot more mechanical knowledge of our cars than I have can help me with this question?

My car is a 2008 MY 4.2 litre supercharged XKR. I replaced the rear silencer / exhaust some time ago for a more 'growly' system and the original OEM part has been cluttering up my garage ever since. I have posted the unit on eBay in the UK at a BIN price of £350 GBP. The RRP for the part new is £1,500 GBP. The exhaust looks a bit cruddy but works perfectly and the valves are both free-moving.

I have a buddy with a 4.2 naturally aspirated XK (2007 MY) and he might like to swap his rear system with my old unit just to get the quad tail pipes.

My question is, will it fit? Does he need to modify the rear diffusor (or buy a new one) so that the quad pipes fit? Anyone got any experience of this?

Thanks in advance, guys.

This is the main eBay photo:



And this is the Jaguar part number stamped into it:

 

Yes he will have to buy a rear diffuser , use a measuring tape to measure the gap on yours then his to confirm

 

Supplementary question. If it will fit my buddy's car, his XK does not have the vacuum-operated valves AFAIK, so he will (presumably) want them permanently open (similar to a fuse 19 delete). Are the valves open in the 'resting' state or closed? If they are open, then I guess he won't need to do anything. If the resting state is closed, am I right in thinking it will be OK to wire them fully open?

 

Thanks George. That won't be a problem. So other than that, my old system will be a straightforward swap? My buddy is a lot more savvy wrt to mechanics than I am BTW. (Not difficult).

 

Valves are open with no power. Should be good to go.

 

Thanks Cee Jay!

 

That's what happens when you pull Fuse 19. The Active Exhaust circuit remains open and no electricity can get to the valve to close it.

 

Funny, I've seen a couple of threads where the XKR backbox is installed on the XK but I think the NA 4.2 sounds perfect. Purrs at idle and roars when you jump on it.

 

I think the main attraction for my pal is the quad tips

 

New diffusers are not too expensive in the States. Adamesh probably has them. It will probably have to be painted.

 

If your pal is attracted to tips, he will absolutely love this Mercedes with an //OMG exhaust!

 

Reminds me of a Bugatti type 57.....not.

 

Thanks. He's pretty handy so he will probably be able to pain the diffuser himself (he has the compressor and spray gear already - he restores motorcycles as a hobby).

I will tell him that my old exhaust will fit his 4.2 N/A but he will need a new diffuser and leave him to decide. Thanks to everyone who has replied.

 

That’s exactly what I did to my 4.2. Got a XKR back box from another forum member. Covered the vacuum inlet tubes to keep them clean. Got an OEM XKR diffuser to replace mine (the 4.2 diffusers are surprisingly cheaper than the 5.0 ones), didn’t even have to paint it, as it was the same color as my original (black plastic).
Yes, I got it for the quad tip look, but the sound is more ‘open’, as the flaps are open at all RPMs. I’ve read on this forum that the XK sound is actually better in this configuration than the standard XKR, due to having just a single mid-pipe silencer, and a different compression ratio.