Hello,

I am new here and I have a 2009 Jaguar XF 4.2 NA. I really want to get rid of the speed limiter! I don't go over a hundred a lot but when I do it is in my 68 Cougar. But driving the Jag doing 70 mph just cruising. When the coast is clear I have gotten on it. When I do, it seems like in a blink of an eye I am only going 125 mph. I know the car can go faster than that! It seems like there is nothing out there unless I have the Super Charged Jag. Which I don't have the money for and I like all my toys Naturally Aspirated.

Some of my Japanese tuner friends tell me that if I swapped a supercharged ECU for my Stock Ecu it would fix it. I dont know if anyone has do something like that but it doesn't make sense to me.


thank you,

Chris

 

Coincidentally i just posted a similar question i have a NA V8 and that is limited to 120mph yet at 110mph it has plenty left in the engine.

 

You would need to get a tune that takes that part of the code out. When I got my custom tune they put the limiter at something ridiculous like 250 mph so I'd never have to think about it. If you switch modules the car won't work at all.

 

Yep what Kyanite said, an aftermarket tune should fix that.

 

Perhaps I am missing something but on this forum people have said there is nothing that can be done to TUNE a NA 5 liter engine, its perfect. So removing the limiter does not require a tune it requires something to set the value. Paying someone a lot of money for setting a value may prove to be annoying.

So where are the 'clever' lads that know the tool or trick to do it. I'm an electronics-software dude so I know it is simple to do but need input on what they are programming - also what is the preferred tool to look at the codes.

Better still if anyone has the ECU manuals in great detail I can come up with a product to do just that. Just need the ECU details etc.

Thanks

 

You can get detailed info by joining the central firm with it - costs $5K or so p.a.

Otherwise get IDS/SDD etc and figure what it's doing during a flash. Costs about $70 and your time.

 

Please help and explain

1) Who is Central Firm ? Need links please
2) IDS/SDD etc what is that ? Need links please

If I can do this I will share with the forum.

BTW my first apprentice job was to program EPROMs :-)

Thanks

 

Go reading on OBD II.

Also look for Mongoose JLR & Mangoose JLR.

Lots in General Tech on this very site.

 

What if I found a 2009 jaguar XK ECU that also had a 4.2 NA and used that with my 2009 jaguar XF??

 

What is the XK limited to?
.
.
.

 

No, you can't just swap in an ecu from a completely different car. Even though they share the same engine the sensors and a lot of other electronics are different. If you really want to do it, find a local tuner and offer them $100 to just go in and increase the speed limiter.

 

Hey guys where can i find the TCU on the 09 xf

 

Probably inside the trans. It's in there if you have the ZF box as I suspect you do.

 

If your goal is only to remove the speed limiter, then turn the dial to S mode and make sure you are in 4th or 5th, should bypass the limiter.

I think with an XF it's also possible to select the speed limiter via the SDD software in Engineering Mode

 

I have a fairly impressive collection of fast driving awards from the speed cops in my day, but I cannot understand a desire to turn off the speed limiter. If you want to go fast, you owe it to yourself, society and especially your loved ones to get the equipment recommended for the speed you want to drive.

 

Mmm I will try that 5th gear ...but dont you stress it out with revs and redline ?

Also what is SDD in Engineering Mode ? How do you do that ?

 

Jaguar XF speed limiter is set because of the stock tires and their rating, not because of the cars performance ability to go faster. The XF NA is spec for 155mph but the speed limiter is set at 120mph !

I could say anyone driving a car over the posted speed limit is putting themselves at risk, society and potentially hurting your family, it is also illegal, regardless of the cars performance - ROFL !

 

PERFECT it works !!!!!!!!!!!!!!!!!!!:icon _banana::icon_smallest :

 

Where can one find a local tuner in his area who can raise the frickin' speed limiter parameter of the 2005 Jaguar XJ8L? Does he have to take it to some dragstrip, and perhaps find someone over there that can do it? No one has yet posted a workable resolution to this thing. Whoops! Wrong forum!

 

The speed limiter on the X350 can be bypassed the same way, put the shifter in 4th with sport mode.