Hi,
Could anybody tell me if there is a similar difference in exhaust sound between a supercharged and a normally aspirated XK as there is between the older S/C and N/A X100 models ? Having drove a new XK, I know it's significantly louder (some will say better) than the previous XK8/XKRs. I'm also aware that although both new models feature exhaust valves, the hardware is significantly different between an XK and an XKR.

The quiet X100 XKR exhaust tone is fine with me. The normally aspirated XK is still OK, as even if it's much more expressive (and pleasant for sure) when accelerating, it remains quiet at stabilised speeds with closed windows, but I wouldn't like anything beyond that...

Thanks for the info !

 

Its not a comparison but this is what an '11 XK-R with 17kms on clock sounds like.

http://youtu.be/6buU8RvugUU

 

Apparently we can't access the video. I guess the 5.0L is yet another story...

 

Well, in the FWIW department, my MY10 XKR Convertible is not nearly loud enough -- even with the top down. Shy of being at heavy throttle, it's hard to hear the engine at all in most situations. My wife always comments when in it how quiet it is inside.

 

Video public now; d'oh!

 

Hi,
At last got the opportunity to check by myself. New XKRs are not that common in my area, but I had the opportunity to test one example this WE. In case anybody care, the funny answer to my question is no ! The new XKR didn't feel any louder than a new XK, actually it's probably the other way round. So, it seems that you either get the bigger growl or the bigger kick when you firewall the throttle...

 

The XK has semi-active muffler which has flaps which open with exhaust pressure and bypass part of the muffler. The XKR has flaps which open under control of the ECU depending on throttle and RPM - these are simple butterfly valves in the outside 2 pipes and bypass the rear muffler box.

If you want more noise from an XKR have a look at the "fuse 19" thread. puling fuse 19 stops the flaps from closing and you'll get a decent growl at low RPMs.

 

To my best knonwledge the XKR has two dual resonators between the catalytic converters and the rear muffler, while the XK has only one. That is likely the reason that the XK appears louder. To my ears my XK is too loud on takeoffs and rather loud on full throttle acceleration. A Jag, for me, should be silky quiet at anything but heavy acceleration. It also drones, probably because of the lack of second resonator.

I just removed the exhaust braces that the dealer installed to eliminate the exhaust drone at 1100 RPM. For me, those braces moved the drone right into my cruising RPMs. I just talked to a muffler shop today about installing a second set of resonators to civilize the sound of my XK. Hopefully will get it done in a few weeks.

Albert

 

Hi,

Jallit : no, in my case it's the other way round : I didn't want to loud a car, which the new XKs are on the verge of being for my damaged ears (to bad for an ex-engine engineer like me !)...

Thanks for the inputs !

 

I have had friends comment (positively) on the exhaust "growl" of my 2008 XK, however, I do not fully understand the "semi-active" feature. Years ago I had a C6 Corvette that had a stock exhaust system that on wide open throttle there were flaps that would open for straight through exhaust. Does the XK have this or a similar design?

 

Will this work the same way on an XK?

 

I have a 2009 XK but like the 4 pipe look. What about swapping out a stock XKR exhaust for the stock XK ? Doable ? Recommended ?

Thanks.

 

No, our exhausts are not electronically controlled like the XKR.

Ours is a passive (strictly exhaust pressure regulated) system.

Vince