Or does it ?

When the revs are taken over 1100rpm on my '07 the and the valve closes there is nothing coming out of the outside exhausts at all. Given that Jagtoes is still feeling some pressure could imply that the valves are actually open. When the valve is open the pressure out of the inside exhausts still feels stronger on mine.

Anyway here is my homework. It is more scientific because it uses SDD to monitor the valve status (0=open, 1 = closed), revs and throttle angle so for an '07 we can conclude that the valve is definitely open at idle.

As the video shows, the valve opens and closes at around 1100 revs which matches the workshop manual table. Unfortunately I didn't take it over 4,000 revs for a sustained period so can't confirm whether it opens at higher revs in neutral.

I will shut up now but if someone can be bothered, it would be cool to see the same for the 5 litre cars.

 

When I mentioned some pressure on the outside tips I assumed it was some leakage. This was shortly after the valves closed. Being my car is on a lift I can watch the valves open and close during start up so I know they are functioning. I can also move the linkage rod to open a valve manually and tell the difference in pressure on the outside pipe. Another indicator is the exhaust tips themselves. Being a little **** I wipe the tips after every ride. If I drive the car in a normal fashion with no DM or WOT when I get home there is no residue in either of the outside tips while both inside tips have gray residue and condensation. Just my observations.

 

What about on a 2014 XKR?

 

Ok, so I have a 2014 xk and I realize it does not have active exhaust however I do have a fuse 19 behind the rear seat panel. What does it control and what effect will it have if I remove it?

 

Your Owner's Handbook should have a description of each fuse.

 

Noticeable difference on my 2010 XKR. Had a great time today cruising around after I pulled the fuse this morning!

 

I'm doing this today

 

As I picked up my 2010 XKR today and had my laptop out scanning it with SDD I thought I would test out a few myths. In this case, the exhaust valve on the 5.0L cars. Using the monitor function in SDD you can check the status of the exhaust valve so can tell if it is open or closed.

My car performs as per the workshop manual i.e. the exhaust valve opens at idle in both park, neutral and drive and stays open until the revs rise sufficiently for it to close. As with the 4.2L, if the engine is cold then the revs will rise above the close point but once it warms up and the revs drop the valve opens again.

As the car comes to a halt the valves open again and also open if you floor the accelerator, as per the workshop manual table.

Dynamic mode does open the valve permanently but Sports mode on its own does not. The paddles also have no affect on the valve in either D or S unless the revs rise sufficiently to pass the usual opening point.

This video shows the valve opening and closing in Park. The top line is the exhaust valve. 0 is open, 1 is closed.

This video shows the valve opening and closing in Neutral.

This video shows the valve opening and closing in while driving in D. Also note the gearbox dropping back to 1st gear when stationary.

 

Interesting but don't quite understand what I'm looking at. It this the vacuum pump going on ? The way I hear my PAE system working on my 2012 is if I go out to the car now sitting in the garage the valves are open. When I start the car the vacuum motors turn on and build vacuum and the valves close. So for maybe 10-20 seconds all 4 pipes are open. After that they stay closed until you hit the go peddle and hold it and around 3500 rpm it gets super loud. Now I can cruise around 1500 rpm and hit the dynamic button (flags) and you can hear the exhaust note change where the valves open. They stay open all of the time. I assume the failure mode is that they stay open. Also if you remove the fuse for the vacuum motor the valves stay open but the other changes in dynamic mode do not happen. So are we talking the same thing here.

 

Yup, that is what I am talking about. Maybe the PAE system is different but my late 2010 model works as per the workshop manual.

 

I have the PAE, and (based on what my ears tell me), mine works like u102678's. Open at low RPM, close at 1100, open again at high revs - unless I put Dynamic Mode on or switch to manual shifting.

 

HI my name is Martin
I Just removed fuse 19 from behind rear seats. Works awsome at low range revs(1100-3500)then V8 sounds like it should in first place
On manual gear shift if you go down from 3th to 2nd gear sound amazing even after proper drive you may hear little bang from pipes, Sooo why spend soo much money for custom
exhaust if XKR has sporty one fitted

Just take fuse out and enjoy

 

Martin,

Welcome to the Forum. I suggest that you create a signature that includes the model year of your XKR and any other information you may wish to provide to make it easier for others to reply to your posts An example is my signature, below. Also, you should update your Personal Profile to include the model year of your XKR.

Early X150 models have 4.2L engines and later models have 5.0L engines. Although the 5.0L engine is more powerful, many Forum members prefer the exhaust note of the 4.2L, particularly when fuse 19 is removed.

So, what do you have?

Stuart

 

Anyone experience a check engine light due to removing fuse 19? I've read several posts that many have removed for extended period of time with no issues. I am new to my '07 XKR (X150) and removed the fuse yesterday. Today my check engine light came on and the vehicle is driving as normal. The vehicle has 78k miles and the previous owner was an older gentleman that I'm guessing did "jump" on it very much by the condition of the vehicle. Any knowledge would be much appreciated. I will have to scan it later this evening to recover any codes.

 

I would pull the code and see what it is. Could be completely unrelated. I have had my fuse 19 pulled for about 5 years, no issues.

 

I will do that this evening and see what I find out. Probably not related and just curious if anyone experienced an issue. Sounds like 5 years and no issues should be a long enough test.

 

As far as I know, the only thing that could happen if you leave fuse 19 out permanently is that the vacuum system or the pneumatic valves might get stuck. I don't know how likely that may be; could be worth sticking the fuse back in every time you go for a service or something like that, just to 'exercise' the system. For the same reason, though I don't have my mirrors set to autofold, I fold & unfold them manually from time to time, just to give them a workout.

 

My car is a 2014 and has no back box at all, so not only am I saving 80lbs in weight, I've got that sound the whole time, plus the burble/crackle on overrun

But at least I know where there's a spare fuse in the car?