Thinking of adding this to my 2007 XK....thoughts ??

Jaguar XK XKR Replacement Exhaust System

 

A shop specialising in exhausts can make a similar set of pipes for much less than £495.

 

I'm sure I could save a few $$ but feel safer knowing it's a 'perfect fit'.

 

Well one was delivered to me about 30 minutes ago, so will be put on shortly and I can then give an informed opinion.


The reviews seem good.


I agree on the price but I am fairly sure this will fit with no issues and that's worth a lot. (famous last words).


BG

 

Appears to be decent quality. Sure shops could fab something cheaper (aluminized steel etc) that would perform the same, but keep in mind this is stainless too (much better appearance). I'm working on something similar for state-side purchasing.

Regards,
D. Fricke

 

What is the pipe diameter (4.2L)?

 

I don't see the X section. I thought the X was where both sides merge to balance out then go to the individual muffler sections. Just looks like to straight pipes to the mufflers. I had an actual X Pipe on my XK that replaced the resonator.

 

Looks like bent 'straight pipes', with a hole cut in the side of each, and then welded together, making a very shallow 'X'.

 

Here is the x pipe in my car. Cost about $300 Australian fitted, so maybe $150 pounds.

Sorry cant get the link to work...it is Southport Exhausts facebook page (Australia), scroll down until you see the silver jag

 

...sigh...technology issues today

 

Stuart, the O.D is about 55-56mm, 2.16-2.20" per my scan data.

Regards,
D.Fricke

 

Stainless steel or not, the price of £495 seems excessive since it also does not include shipping, any applicable duty or taxes and installation labour.

The important question is: what exactly is being accomplished by this modification? If it is supposed to increase engine output in horse power, where are the dynamometer test results for the 4.2 litre engine?

 

I am curious. I have looked but have never been able to find a true A-B comparison dyno test of conventional "H" pipe vs. "X" pipe. I see that aftermarket tuners like Magnaflow always use an "X" pipe, whereas OEM manufactures always seem to use the conventional "H". It would seem that the cost differential between the two is marginal, so why shouldn't OEMs adopt the "X" connection between left and right cylinder banks? As this connection occurs downstream from the cats it should have no effect on emissions.
My guess is that the "X" connection is based on the theory that exhaust gases from left and right banks more or less follow each other creating less back pressure. Most cars have a "cross plane" crankshaft, which causes firing between left and right banks to be a bit uneven, which just might cause a genuine blockage at an "X" connection.
Contrasted, a flat plane crankshaft has even right/left firing order; and perhaps here an "X" pipe would be beneficial. Ferrari for years, and now the new Mustang GT350 have used a flat plane crankshaft.

 

The H-pipe is typically used to even the pressure between the banks when using a cross plane crank. Additionally this does have a slightly different sound than the X (More muscle car). The X would add a small marginal cost difference.
The X design is more optimum in the higher RPMs and will benefit more than the H in this area. Once flow has reached a high enough velocity the H will lose its efficiency.
Pertaining to dynometer comparison, adding in an x-pipe will be noticed in the higher RPMs but more so with a removing a restrictive system. The jaguar system is not that restrictive in stock form. When doing performance add-ons (Supercharger increase etc.) this is where you will notice more benefit.
The sound is the main benefit to end-users, the performance with a stock engine would most likely only be a few hp in higher RPMs.

Hope this helps,
D. Fricke

 

When I put the X pipe in, the exhaust note was more of a howl than a throb, though that might be because the resonators are taken out. Given that I reckon the 4.2 engine note is perfect as it is (just needs to be louder) I wouldnt put an x pipe in. With my 4.2 XF I put in the Paramount exhaust which essentially just replaced the back mufflers with smaller ones. I think there was a more hardcore version where they were deleted entirely, and that would cost next to nothing.

 

Which, presumably, is why Jaguar never claimed a increase in HP for the Performance Active Exhaust. However, when I interviewed one of the team that developed the 75 (which has 530 PS), he said that some of the HP gain was due to the x-pipe exhaust.

 

I have the Spires X-pipe (what they call their "stage 1" exhaust upgrade) which looks, to all intents and purposes, identical to this Adamesh one.

Sound-wise, a little more bass maybe (the result of ditching the center silencers/resonators perhaps), about 15% to 20% more volume but no real, appreciable difference in performance. My car is a 2008 4.2 XKR so I doubt very much I'd feel a difference of much less than about 10% either way and I'd be even more surprised if simply changing this part yielded a bigger gain than that.

IMHO the biggest net gain is more smiles, due to the extra noise, and if anything the car feels a touch more exciting for it. That being said, I personally feel I'd like a bit more so I'm now considering changing the stock back box too

 

As mentioned above... Smiles

 

Tasty, tasty, very very tasty...

Tunnels & empty parking buildings, the best echo chambers.

 

My favorite thus far is cruising through the city with tall buildings. You can hear the crackles/pops blocks away. Every person turns in awe; husbands drool, wifes smile, kids are amazed. I do not think it is possible to meet a person that does not like these cars.

If anyone has the Adamesh section, or MBK follows through with purchase certainly add some sound clips.

I'm trying to wrap up fixtures to build a similar setup, but I've been tied up with the headers design.