I've heard that the tune for the XKR-S with raised speed limit and increase from 510hp to 550hp lives on the XKR ECU, and just needs to be turned on.

Is this true, and has anyone successfully done it?

Is there a set of instructions available for those of us who want to attempt it on our own?

There's not much available on the forum regarding this, so I thought a dedicated thread could be useful.

I'm pretty sure there is already a thread about this. The gist of it is yes, but you need an X-Pipe.

Easy enough , with the right tuner you'll be able to get just over 600hp with nothing but a tune and X pipe.

The x-pipe was done years ago... But I like the idea of using a safe factory tune that won't risk shortening the life of the supercharger or other drivetrain components.

510hp is already more than enough, but if there's a "setting switch" on the ECU to change over to the XKR-S tune by anyone with SDD or a similar tool, that sounds like a really appealing way to get an easy extra 40hp.

call a real tuner

Sigh... great input there, as always.

Love the old 'Why do forums even exist' response, when the answer to nearly every thread can be 'go to a mechanic'.

Tuners are a thing. We know that, and it's not what this thread is about. Plenty of other threads already cover shop tuning and the companies that do it.

There are plenty of posts that have already covered these questions. I would suggest using the forum search function.

One of the most informative posts about this is this one:
https://www.jaguarforums.com/forum/x...esults-147772/

That's not what I'm asking either... Not sure why you'd assume I don't know how to search, then post a link to a thread that covers a different topic. I read through that in it's entirety before posting my question. It mentions flashing the ECM with an XKR-S tune by getting it from an XKR-S vehicle, not switching to a tune that may already exist in the ECM.

That thread is basically why I added the x-pipe immediately after buying the car... To prepare for what I'm asking now.

I read that it was possible to switch tunes from XKR to XKR-S by simply manipulating settings on the ECU via SDD, but I wasn't able to find any sources that explained how it was done.
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If what I'm asking is not a thing, then that's fine. It's why I asked the question.

The XKR-S tune is NOT in the ECM, it is in SDD.

Great info. Do you need access to engineering mode to flash it?

Are there any screenshots or in-depth descriptions of the process available?

I'm asking because if I take this to my independent tech to see if he can/will do it, we can walk through it together and see how it's been done before. He's hesitant to use SDD for things like this because he knows how powerful of a tool it is and the damage it can cause if used improperly.

This is me being proactive and trying to do my homework, and hopefully help others who might want to do the same thing in the future.

Generally SDD will do its best to prevent the wrong software being flashed. Your desire fits that situation.

If it has been done, there must be a process. I'm trying to figure out what that is, so I can share it with my independent tech.

@TraxtarXKR

Firstly, get off your high horse for a second. All I've done is try to help you and you seem to only want to give back attitude. How am I supposed to know what you have or haven't read before.

I haven't assumed anything. What I did was suggest that you use the search function as when I went to use the search function, I managed to find a few threads about this subject. On the first page of my search results is a relevant thread about an individual who had the map applied to his car and some of the details of how he managed to do it.

Even after all of this, I will still attempt to help you and share information:


I've heard that the tune for the XKR-S with raised speed limit and increase from 510hp to 550hp lives on the XKR ECU, and just needs to be turned on. Is this true, and has anyone successfully done it?

Yes and no. Yes, it is a configuration change BUT it does require a firmware change first. The configuration change lies within the BCM/GWM. The firmware change needs to be applied to PCM.

Is there a set of instructions available for those of us who want to attempt it on our own?

Generally people don't tend to share this type of information. There are mentions of it scattered across relevant threads but people have tried this before only to message me (or perhaps others) and ask help with fixing a bricked module or saying that the car won't start or now how an engine management light or various new DTCs.


The best piece of advice if you want to get this done is either get someone who is really capable with SDD (there are a few on this forum) to remote onto your system and do it for you or seek a local Jaguar specialist. In reality, he's got to be a little more than a specialist as most specialist don't know how to do this.

The one thing I would say if you are going to go down the "remote" option is this, you can cut corners on a some things i.e run jump leads off of a running car instead of purchasing an expensive Battery Support Unit. Just try not to skimp on the VCI. Try to use a genuine product and you'll have less issues down the road.

It's super-easy and doesn't require anything special besides SDD and Windows File Explorer and some typing and mouse work. This does NOT raise the Vehicle Speed Limit!!! This DOES require the resonator delete.
I sent you a PM two days ago, but you never replied to it so I don't know if you read it or not.

Although this can be done additionally through SDD to raise it to the R-S's 186mph.

..........which I have ALSO done, but it requires different files and a specific version of SDD.

Can be done with any version of SDD. No specific files needed. It's just one parameter (byte) that changes from 0xA8 to 0xAC.

MoJo88, we've all been of forums long enough to understand what "do a search" implies. In Texas, women love to say "bless her heart", but we all know what she really means. I've gone through multiple foums and subgroups, and couldn't find what I'm looking for... If the XKR-S tune is on the XKR ECM, and if there are exact instructions on how to enable it.
Your response to tell me to search wasn't helpful. That's all there was to it. Sorry if I offended you. Thank you for still being willing to help.

I understand why folks wouldn't want to be accused of being responsible for someone else's car having issues because of something they wrote in a thread.

I'll look further into the connection methods for a remote session... It already sounds like this is well beyond the skillset of my local independent, and I doubt he's willing to spend time learning something for what's likely the only customer he'll ever have that makes such a request.

I just saw your message and replied. Thanks for taking the time to help privately.

@TraxtarXKR

It's all good. Hopefully your correspondence with Cee Jay gets you to where you want to be

Again the map is NOT already on your PCM, it's located in SDD and it's NOT an option to do, it's a "hack" so to speak and it's best left to a specialist familiar with how it's done. As has been said my Mojo, a lot can go wrong or it may not work at all.