I get to drive in Germany a couple of times a year and would like to get to the true top speed of my convertible.

The new PZero's I have are rated 'W', 181MPH, so no worries there, traffic permitting that part is not as easy as it sounds.

But what is involved in 'delimiting' a 2003 XKR?

Just change the ECU?

I seem to recall reading somewhere that there are multiple layers of embedded code that reassert themselves even if you 're-write' the first layer of code with an ECU swap.

Other mechanical or software issues to address, ie transmission software codes?

Is there anyplace to get an ECU unit that is de-limited?

What about front end lift issues at high speed, even with the cooling and vents of the XKR?

How difficult is it and how expensive is it to get it done at a dealer or a shop in the UK or France?

Does anyone have experience with any of these issues or suggestions where to find a shop to do the work or get the parts?

thanks,

jamjax

 

You don't need to replace PCM , just it needs to be tuned or reflashed by professional mechanics . My dad's ride upgraded by PCM tuning but since this is Jaguar it may require different skills
As I recall, Arden can do it for you but cost a few grand . I don't know other sources may be dealers can guide you

 

You can have the 155 limiter removed by someone who can do a remap..... If you are over the UK at all have a word with Viezu, costs around £600ish, for that you obviously get the remap and delimited
Tell them Tony from Paragon put you on to them and they will look after you.

 

Thanks XKRacer/Paragon;

I was hoping you would check in on this question.

I appreciate it....thank you for the referral to Viezu.

You guys at Paragon don't do this modification?

Any idea what a delimited XKR convertible should do as a top speed?

cheers,

jamjax

 

I could've sworn I read somewhere that the speed limiter can be deactivated by simply removing a fuse for something else which disables the speedometer, leaving the ECU with no knowledege of the actual speed. If you have a GPS which can report your speed, that might be a fair bit less costly than having a remap done.

 

If that works it would probably be good enough for an occasional blast up the Autobahn.

 

Hey Ohio;

Thanks any idea where I could find that info on the fuse?

It is an intriguing idea....does the Sat Nav in the XKR work in conjunction with the Speedo?

I have a top of the line TomTom that is pretty good I could use....

Where in Ohio are you....my old stomping grounds were Cleveland Heights and Chagrin Falls.

Cheers and thanks,

jamjax

 

I had a 80 hp economy program flashed on my F250 Supercab, and I went from 18 MPG to 20 MPG on the highway. I originally could just chirp a tire from a dead start, but I can now seriously burn rubber. 60 MPH to 80 MPH is an incredible 4 seconds flat. I have no desire to test the top end speed of any 7000 lb. vehicle. My point: Quality ECU mapping can improve your driving experience on some cars/trucks dramatically.

My first question is how many RPM's does the XKR turn @ 155 MPH? If you're only going to get a couple of MPH more, the ECU flash would be a waste. Now, if you're going to get 15 MPH, it'd be good for the autobahn.

Second question is what would a quality ECU program do to driveability of the XKR?

Would a remap bring a ear to ear smile on your face?

 

jamjax,
I thought I read about it on this forum, but I don't have any links available. I think it might be a fuse that controls the DSC, I'm really not sure. I believe there is a sensor somewhere on or near the rotor which sends a signal to the ECU indicating the vehicle speed, that is what needs disabled.

I'm not too far away from your old stomping grounds, I'm in a small township near Oberlin. Just put my XK8 away for winter storage this week (I'm sure you remember Ohio winters and salted roads). Enjoying Switzerland?

 

Bama;

Interesting point about mapping but the key here is the delimiting the top speed that goes with it.

The top speed is rumored to be about 171-175 without the limiter...some folks have seen higher than that but take that with a large grain of salt given the vagaries of Speedo accuracy and tire sizes.

So yes there is your plus 15MPH before you even fiddle with the efficiency of the engine with remapping.

When I get some answers from Viezu that XKRacer/Paragon Designs mentioned I will post them re: performance gains.

Right now they claim on their website that every facet is improved from MPG's to speed and acceleration.

Will be looking closely at this but have to think it is worth it on the strength of XKRacer/Paragon's reputation alone.

If he says it is good then it most likely is.

cheers and fly low in that Semi "Light" monster of yours.

jamjax

 

Ok I will tell you a little story..... a true story as I was the co driver in this case

I went on a Jaguar Milbrook day, this was back in 2004/5 just before the release of the final facelift of the X100, one of the things they showed us was how good the ABS was, my driver removed some fuses from the lefthand side engine bay fuse box, this switched off the ABS the traction control and the speedo, we drove through the skid pan and the car was all over the place, replaced the fuses and bingo, a perfect easy drive, he then removed them again and asked me if I fancied a fast drive around the Bowl, of course I agreed, he then tells me the removal of the fuses also delimits the car, we was in a coupe and not a convertible but the fastest we could get before things started getting 'squirrelly' was 179mph read by his GPS monitor. And no he would not reveal what fuses or whatever he did in that box.


Getting back to jamjax's question, remapping a car takes a lot more than a lap top, anybody can load a map but to make it work right you need a rolling road, a VERY expensive bit of kit. Viezu is the only company I know that actually writes a map as apposed to uploading a few and seeing which one works best, sure I would love to be able to do it, but it would mean I would have to diversify what I do and I rather stick with what I like

 

Racer,

Great Story and info.

I have already written to Veizu and asked for an appointment at their Slough Branch.

Thanks again,

Jamjax

 

Thanks Ohio,

You can see that Racer is on top of it and as always gives great advice and info.

The only real difference between Ohio and Swiss winters is the salt....they use sand here.

But even with 30 years in Sunny California and New Mexico I remember how to drive in snow and more importantly how not to drive in it.

Got to Oberlin a couple of times in my mis-spent youth.

Outside of Cleveland was where I drove on the freeway, age 15, for the first time by myself in, a "Borrowed" from my father's service shop at Jaguar Cleveland, a BRG 1965 XKE Coupe and I distinctly remember my dissapointment that it would only do 120MPH on a speedo that went to 160MPH, due to US gearing.

Hence my desire to repair that 'defect' in my history that my college red 1959 XK150, bought with my college loans while at UC Berkeley, did not quite scratch at about the same top speed as the E-Type.

My mother lives just outside of Chagrin Falls and still has a barn full of classic MG's, including my Red 1960 MGA that has been in the family since '62. She has been president of the local MG club for the past 11 years following my father's ten years as Pres. before that.

Legend has it that I came home from the hospital on a winter's day in a topless MG TD....so you could say that Winters and Speed are in my DNA.

But I write this from holiday in nicely warm Siracusa, Sicily at my favorite B&B literally over hanging the Med, so I don't forget the sun either by driving a circa 1960's white Fiat Cinquecento-500 with a folding sun roof.

Plenty of grins with three adults in it including my brother in law at 6'4" nice and comfy as shot gun, and my Genius-Italian Super Model wife draped on the back seat, OK, OK I exaggerate .... she is squeezed in there rather than draped.

cheers, jamjax

 

"The only real difference between Ohio and Swiss winters is the salt..."

With U.S. gasoline @ $3.50 per gallon, I thought the difference between the two was about $4 to $6 per gallon.

With O'Bama's proposed 56.2 MPG CAFE standards by 2025, we should look for EU type road taxes. He probably thinks windmills will produce enough electricity to power personal transportation--not.

Enjoy your present incredible road cars, as the future of motoring is unknown.

 

For the 2003 XK you would remove F4 (5 amp) fuse in the engine compartment fusebox to disable the ABS/DSC. The INST PK and ECM need the speed input on the CAN bus for info.

I don't know if this will limit the car to 155MPH but it sounds about right.

bob gauff

 

Hey Motor;

Thanks for the tip.

Does this disable the speedo too?

Or is that another fuse?

Racer implies that was necessary to make the top speed run he did on the track with the Jaguar Factory Driver.

cheers,

jj

 

"my driver removed some fuses from the lefthand side engine bay fuse box, this switched off the ABS the traction control and the speedo"

"And no he would not reveal what fuses or whatever he did in that box"


The fuse disables the ABS/DSC module so the output to the INSTPK is also disabled. No output from the ABS module = no input to the INSTPK.

I have not tried it but that is probably the fuse that was removed to disable the input to the speedo and ECM.

 

Thanks MCM!

I will give it a try and let you know when I do.

cheers,

jj

 

Bummer!

Just heard back from Gerald Morten at Viezu and they don't do remapping for the '03 XKR.

Any other ideas out there for removing the 155 MPH speed limiter?

I had the impression that dealers could do it if you could find a sympathetic one?

Which would beg the question if any one knows of such a Dealer in the UK or France, Switzerland, etc.

cheers,

james

 

I might know