Fuse 15 Query

[Cliffedge]

Having read a lot of details about removing fuse 15 on 2019 models onwards, can anyone confirm that doing this gives the same sound as just switching off the exhaust valve in the centre console or switching it in to dynamic mode?

I have a MY21 V8 and it’s far too quiet (coming from a TVR) even with the exhaust valve open, but haven’t tried removing fuse 15 as I think it wouldn’t be any different to flicking the switch?

I have been considering the Paramount Performance exhaust modification but at around £2.5k it’s a bit pricey.

 

[scm]

No personal experience, but from what I've read it seems that with the fuse in place the car's electronics still messes with the valves, while removing the fuse takes that interference completely away. Simple thing to do is try it and see!

 

[WShudds]

Removing fuse 15 on mine does improve the exhaust notes and volume under 2.5K RPMs compared to putting the car in dynamic mode.

 

[jagseven]

It’s definitely different from just pressing the exhaust button - removing the fuse keeps the valves open even at low revs.
The downside from my experience is it introduces a drone when cruising.
An aftermarket exhaust might be the only way to get the exhaust sound you want.

 

[YorkshireSam]

From experience, it makes a very significant difference on the new shape V8s (P450 and P575).

You'll get loads more overrun crackle lower down the revs, and a more visceral exhaust note overall.

Please don't spent 2.5k on a new exhaust without trying it. You probably won't need anything louder.

It's not the same as pressing the active exhaust button. It's a different noise entirely.

Here's a photo of the fuse to pull, taken standing by the passenger side wheel.

 

[Cliffedge]

Thanks everyone, as always very helpful. I take the fuse out and see how it goes.

 

[scz4]

As someone looking for a P450, what's the process when removing the fuse? Since the valves don't open until 3500rpm, is it just a case of putting it in dynamic mode, rev to 3500rpm in neutral and have someone remove the fuse as soon as they open?

 

[B8RS4]

Should pick a P450 up next week and this is the first thing I want to try. Having read lots on here I will be turning the engine off, having a gander to see if the flaps are open and then pulling the fuse.

 

[Billymcmred]

As someone looking for a P450, what's the process when removing the fuse? Since the valves don't open until 3500rpm, is it just a case of putting it in dynamic mode, rev to 3500rpm in neutral and have someone remove the fuse as soon as they open?

I think when car is not running valves are open removing fuse before starting leaves valves open
When I start mine (P450) it’s louder for about 30 - 60 seconds before quieting down I’m guess valves are closing to quieten it down
I’m sure someone will confirm or update with “correct” procedure to remove fuse

 

[WShudds]

Valves open when the car is off ahead of the next ignition and shut after a few or several seconds depending if the engine is warm or cold. So just switch the car off, remove the fuse and be happy

Please note that an error code (open circuit) will be stored on the ECU until you replace the fuse. It does not trigger the engine management light and there will be no other dash warnings. It may be wise to replace the fuse ahead of a service especially if you got a Jag warranty.

 

[Jedster]

Sorry for reviving tis thread, but I cant quite find a definitive answer for my query with regards to pulling Fuse 15.

As a happy owner of a one month old P450 I happily pulled Fuse 15 and instantly noticed the change in exhaust note at lower revs with more popping, crackling and all the stuff that makes us smile .

However I have recently been told keeping your exhaust valves open all the time could affect engine management or damage the valves. I'm intending to keep my P450 long term so was wondering whether I should plug Fuse 15 back in just to be safe

Can anyone give a definitive answer as to what long term affect keeping the exhaust valves open all the time could have?

Thanks in advance

 

[mickjaguar]

I can't see how having the exhaust open would damage valves or the ECU. The dynamic setting and exhaust button in the early cars just opened/closed the exhaust on demand. I used to drive around, in my 2015 car, with the exhaust open the majority of the time, as most owners probably do. The feature was changed from 2018 to meet stricter noise regulations, so that the valves just don't open as early or on demand now.

In theory the problem could be that the values might sieze in the open position, through lack of movement. Although, these the later cars have valves with improved flap bushings which aren't as prone to siezing up like the early ones. I haven't heard of anyone that's had a Fuse 15 problem over the last 3+ years since I've had one of these models (in the UK or US). What you don't want to be doing is inserting and removing it too often, as the fuse box isn't really designed for that. Rumour has it that someone forgot to put it back when their car went in for warranty work, but the technician just wanted to know what had been done to the exhaust to make it sound better .

 

[WShudds]

Just to add to the above bear in mind that an error code will be stored on the ECU when removing the fuse. Putting the fuse back and clearing the code might be wise if you ever have to sell the car.

 

[YorkshireSam]

Sorry for reviving tis thread, but I cant quite find a definitive answer for my query with regards to pulling Fuse 15.

As a happy owner of a one month old P450 I happily pulled Fuse 15 and instantly noticed the change in exhaust note at lower revs with more popping, crackling and all the stuff that makes us smile .

However I have recently been told keeping your exhaust valves open all the time could affect engine management or damage the valves. I'm intending to keep my P450 long term so was wondering whether I should plug Fuse 15 back in just to be safe

Can anyone give a definitive answer as to what long term affect keeping the exhaust valves open all the time could have?

Thanks in advance

I've run mine without 15 in the past. It does sound awsome. It's currently back in after I had to replace a faulty exhaust O2 sensor.

Yes, F-Type O2 sensors tend to be a bit fragile. However, it did get me wondering whether the extra pops, crackles and changes in exhaust flow after removing fuse 15 could lead to O2 sensors sooting up/ malfunctioning.

I believe 'pop & bang' remaps which are popular on some cars now can put extra strain on exhaust sensors and cat systems, leading to premature wear.

I'd be interested to hear any other views on this.

 

[WShudds]

One of my downstream O2 sensors failed with 29K miles and 3 months after buying the car. Not a big deal and it got covered by the RAC warranty. Shortly after I decided to remove F15 and it's been running absolutely fine. The extra noise is worth it IMO.

I wonder whether the unrestricted exhaust might have an overall positive effect on parts and performance.

 

[cj10jeeper]

I’d the question into two parts.

Whether the bypass valves are opened or closed doesn’t make any difference to the pops and bangs, other than making them more audible, so on that part I’d say. Big benefit to those who like the noise at all times and perhaps very minor benefit of being a slightly less restricted system.

However, pops and bangs are a result of fuel being fired on the exhaust stroke either by retardation, plug firing or fuelling, typically controlled by a part of the ecu map. That can be an issue. Viezu make reference to it ‘cremating the exhaust valves’. I also cannot see how you can in effect run endless explosions in the exhaust system without it having a negative effect on the components in and part of the exhaust, be it temperature, shock, etc.
How much is somewhat unknown, but we can assume JLR thought it acceptable within the standard maps of the ecu and system, but likely didn’t plan for removal of a fuse, or. Driving in a manner to induce them continually.
I therefore use the feature of pops and bangs, but not to excess.

 

[Jedster]

Great answers all! Its great to hear some differing opinions on this. The only downside being is that one moment I'm thinking of popping it back in and one moment I'm thinking I will definitely keep it out.

Pops, bangs and crackles aside, I'm loving the F-Type, its a fantastic car to drive!

 

[DOC IW]

There is a fairly easy DIY mod to make fuse 15 switchable with a remote control rather than faffing under the bonnet to physically pull and replace the fuse. It allows the car to roar when wanted, but purr quietly when preferred at the press of a button.
It was first described by a member of the US F-Type forum, but has now been described here on our UK forum too.
Search “Fuse 15 remote control” on this forum.
It has come to be known as the “claws out” mod on the US forum.
I have done this for mine and it works really well.

 

[Magnus_Nara]

I’ve got a 2020 P450. Had the fuse out (audibly louder) even in dynamic or with the valves open.

Has anyone seen the posts saying that fuse 15 is also for the EGR valve and the EGR sensor will fail as its continuously trying to close the valve so burns out?

With the fuse in, the car gets louder at 3.5k. (I do press my exhaust button/put it in dynamic) but it sounds dead compared to fuse out.

My big question is, is it actually the EGR valve being forced open all the time that makes the difference as I'm sure my back box valve is open all the time.

Thinking about going to mod stock to do the back box but not sure it will actually make the difference I'm looking (assuming the EGR is at the back of the engine) for and I think 200 cel cats might be too loud.

Trying to avoid getting £750 into modify the OEM exhaust/look for a switchable fuse just to find in going to need to go full after market

 

[WhoKnows]

I've not heard of the EGR being impacted, but have heard of the GPF regeneration potentially being impacted on the later cars if that is what you meant.

You can read about that here: https://www.ftypeforums.co.uk/viewtopic.php?t=9349

Also a long thread on the US site, where DMeister found a controller from Germany which allows you to control the valves at will whilst leaving in fuse 15 and apparently not stopping the regeneration. Not cheap but cheaper than modifying the exhaust I expect. Post 97 for that controller:

https://www.jaguarforums.com/forum/f-type-x152-72/psa-fuse-15-removal-290806/page5/

I've not gone that route as I don't often enable my "claws out" mode so hoping I'll be ok