I think we might be on to something...I bet your 2/16 build has the K309 software, and not the JTB update? However, I find it hard to believe my 11/16 build would not have the JTB update. Both ek993 and zmoothg had the JTB update and the new exhausts, and their valves were working properly after the replaced exhaust.

 

on my '15R with only 4000 miles on the odometer, drivers side valve is fully open while passengers side is missing maybe something like 25% but it is still open.. seriously ?? I don't see myself getting the exhaust changed under warranty because of that ? is it worth it ?

 

Appreciate you sharing, another data point. Just trying to make sense of why some have both fully open while others do not.

 

I'm not having them change any exhaust.

 

I did talk to service again and he said K309 is listed to be done. We'll see what happens. I also asked him to look into the JTB update.

 

That's a very surprising response you got. TBH I never looked all that closely at the valve control setup, but I don't recall a single vehicle where I have ever seen separate right & left side valve controls. The valves are actuated by vacuum. The vacuum is generated by a pump, and the flow is controlled by a simple electric solenoid/valve. So the command from the ECU opens & closes the valve to allow it to flow. Most of them actually work counter to the way most people expect - the default position of the valves is open, and he vacuum pulls them closed.

So in order for the car to have one valve set to open more than the other, it would require at the very least multiple electronic flow controls, even if they ran off the same vacuum pump. Every other car I've seen has one vacuum source, one flow control and then the lines are split to run to 2 valves.

The other challenge I see is, that the valves are set to actuate at a particular pressure threshold, think it is 1 bar. If the pump is designed to produce 1 bar of pressure, and switches on when the pressure drops below this, then you would need a pressure regulation ability. The flow controls are usually on/off. Meaning that to control the valve operation it's either open or shut. They don't have the ability to pressure regulate, just to open to allow vacuum, and close (and bleed vacuum) but it's pretty much binary on/off.

 

Surprised Stuart, or is it a load of crap?!?

 

Sorry I have been gone for Monterey car week. No I spoke with my dealer there is NO such software that makes one valve open more and less than the other. The vacuum applied to both are the same. I mean literally the same. Here are the schematics (attached). It is impossible to control them separately. The exhaust is faulty & they are being too lazy to replace it.

 

I test drove the MY 2017 R and it did not it cut out like mine has been. We took my car back out and I was able to demonstrate the problem again so they are taking the car back in to look again.

I can confirm the valves are both fully open when the car is shut off on my MY 2016 R.

Fyi I've been working with Mike at JNA customer care. He's the only Mike there.

 

Thanks Ritzy. It sounds like your issue is probably related more to the K309/JTB software update.

 

And this is the latest from my dealer...
There is no confusion regarding the K309 software update and the software update that partially closes the exhaust valve. In 2017MY, the PCM already has the latest software to partially close off the exhaust to lower the noise level as well as extend the 02 function as per the engineer. Unfortunately there is no way to revert the software backwards. Once they make a change we must move forward with it, I am sorry if it is not what you want but my hands are tied with that one.

Keep me posted with what you find out from your dealer

 

Try moving the butterfly by hand. Maybe something is stopping it from moving. I just did this on mine, it moves fairly easily. It opens just by spring pressure. The vacuum pulls it closed. There's a little lever/arm/pivot on the top of the outer pipe, on each side.

 

On my 2016 R the passenger side opened 3/4 while the driver's would fully open... I messed with the valve closing the solenoid with my hand. Didn't really feel like it was binding BUT it did have a rough spot on the bottom side of the solenoid arm. Took some 600 grit sand paper and gave it good rub then sprayed a little wd40 on a rag to clean it up. Closed it manually a few times and now it works perfect! Opens fully for me 100% of time. Not sure how long the fix will last but it only took 10mins of my time.

 

is there really a difference in noise between 75% open and 100% open? Once people are aware of the percentage, does self fulfilling prophecy come into play? My 17R is loud as ****. I'll take a look at my valves and if they are partially closed, I honestly dont care.

 

There is a considerable difference with the noise and that is how I first noticed that something was off about my exhaust and to my surprise the passenger valve was not opening completely. They replaced the exhaust and all was well, but I eventually bought a VAP exhaust because it sounds even more amazing.

So short and sweet, yes it makes a difference. It also results in a fluttering sounds at high exhaust flow when partially opened.

 

More like paranoia!
For me personally, it's likely a combination of things:
Going from a '15 M4 (loved it, but embarrassingly sounded like a lawnmower) to a '16 Coupe R, there was such a dramatic/huge change in sound exhaust/V8, that I likely imagine my '16 being significantly louder than my '17 Coupe R.

Adding to my possible perceptual confusion was then me changing from my '16 Coupe R to a '17 M3 ZCP which was such an improvement on so many levels, one of which being the sound/exhaust. And now I'm back with a '17 Coupe R, which perhaps for me may not have been as such a dramatic change coming from the '17 M3 ZCP as compared to the '15 M4. Keep in mind all these car changes happened in a matter of months, not years, as I suffer from a severe case of Vehicular-ADHD! I wonder how long this '17 R will last?

Furthermore, I imagine the exhaust still needs more time to break in, with me only having 800 miles on the clock.

Added confusion occurs when dealers then give me some BS explanation (i.e., "customers complained it was too loud, so '17MY had a software change"--seriously!), while folks here experienced similar symptoms with their exhaust valves and ended up having their exhausts replaced which then resulted in both their valves opening fully--despite this reported software update to "quiet the exhaust." But then I see other folks with earlier model years experiencing the same issue with their valves. Jaguar's inconsistency/QC feeds my paranoia!

BTW, I'm curious what you find when you check out your valves.

 

Is there a way to keep the valves open at all times ? By pulling a wire or whatever ? That would be the easy solution.

 

The WD40 will burn off. I personally would try using some never-seize (thread lubricant). A full synthetic engine oil might survive the heat as well.

 

Unplug the vaccum lines where it connects to the exhaust.

 

Pull the fuse for the vacuum pump, if you have it.