Has anyone done a rwd to awd conversion on a 2014 xjr? Or if it’s even possible

 

manny69, possible, anything is possible with enough money. Worth it cost wise, probably not. You would be better off just trading in the one car to get the features you want in the AWD car.

Now, if you are looking to make a 5.0L supercharged engined car AWD, that is going to cost even more. In my discussions with Jaguar engineers and high ups with Jaguar, they had contemplated doing a 5.0L supercharged AWD car, but the transfer case was not capable of handling the power even the lowest powered motor made (can only handle 458 hp supposedly). So, if you have a 5.0L engine and am contemplating this, now you are adding to the cost a one off transfer case setup.

 

@manny69 , Welcome to the Forum. You'll find many knowledgeable and helpful members here. I noted from your Public Profile that you joined on January 4, 2024 and this is your first post.

We need you to help us help you by creating a signature that includes details as explained in this thread:
* New Members - a MUST read if you have just signed up *

That autmatic signature will help since we won't have to keep asking about details of your XJ and where it's located, as climate and other members near you matter. I understand your need for privacy and anonymity; your state and general location will suffice.

Thanks for understanding.

 

I take it that the v8 f-type awd transfer cases are not compatible with the XJ?

Regardless, do you have a general idea of what the cost might be? Is this like 5k, 10k, 50k, 100k+? (I'm very new to car things so I really don't know what reasonable values are for these kinds of mods)

 

Bismark, to keep things easy, yes, the F-Type and the XJ use common components (note an asterisk with this!!!!!!). So, in theory, you can take the drivetrain from out of an AWD F-TYpe P575 and put it under the XJ. The XJ is going to have the mounts for everything. How much adaptation that may be needed is hard to say as I am not sure of the exact model transfer case the F-TYpe used. But, a little bit of metal working should overcome that. The bolting should be the same as both cars are using common components. The big unknown I would say is the ECU and its programming. NOt sure how much the ECU/tranny computer would look at the transfer case to affect how the motor is controlled. I know the V6 and the V8 have different oil pans to account for the front differential. So, there is that aspect to deal with. But, I am sure this has already been overcome with the F-TYpe P575 motor. I Think the easiest way to do this would be to take a 3.0L XJ, pull the motor/tranny/transfer case and then slide the F-TYpe motor/tranny/transfer case into place. Then you have the aspect of transferring over the wiring harness with it. From there, you would need to use SDD to somehow make the two become one. SHould be able to do that as the two systems will be using common language.

Please keep in mind that I am looking at this from a fairly high level view. You are going to have to get additional power sources for some things out of the fuse boxes. A wiring harness for the transfer case (if there is one). Then you have converting the brake system over to the larger calipers and rotors (this is the easiest of the mods). Then you can even start tossing in the idea of the exhaust cutouts and whatnot that the F-TYpe has.

I would say you would be most likely looking at a $25-30K job with most of that being in obtaining a useable F-TYpe P575 drivetrain. The slightly cheaper method would be trying to find the front differential and the oil pan setup from out of an AWD F-Type and then getting your hands on a transfer case. Going this way, you may be able to get the cost down some, but not sure how much we are talking here.

Granted, how much power are you shooting for? It seems to me that members here have modified their 3.0L engines up to around 515 hp with the AWD system (this is pushing the limits of the transfer case, but haven't heard of any issues). This could be all done for a few thousand. Is the extra 60 hp that much of a deal breaker?

 

@Tuning@VelocityAP Would you happen to know how the ECU/TCU interacts with the AWD system, or is this just uncharted territory?

That depends on how much power the VAP Stage 4 for the v8 will make >
That does make me wonder though if the f-type transfer cases wouldn't be able to handle more power themselves. Perhaps there is a way to limit the AWD system so it can't give the front wheels too much power?

 

Bismark, what you are talking about with limiting front end torque is going to require a different style transfer case. To the best of my knowledge, the XJ's transfer case is a locked design. By that, there is always a certain amount of power going to the front and a certain amount to the rear (percentage wise). This does not change. The dynamic traction control simply limits the overall power and applies the brakes to certain wheels to prevent them from spinning. What you are talking about would require an electronic clutch built into it that would allow power to be shifted around. For example, in my 97 Expedition, I have 4x4 and AWD. I found this interesting and investigated why the truck had both. With the truck, 4x4 means it shares power 50/50 front and rear. In AWD mode, the truck puts 10% power to the front and the rest to the rear. As the rear tires start to slip, the clutch in the transfer case engages more, transferring power from the rear to the front, until the 50/50 power split is achieved or the wheel slippage is stopped. So, the power to the front is always in flux. Jaguar calls their system "AWD" because it is not a 50/50 split front to rear, it is more 40/60, with a bias to the rear. This gives the car more of a "rear wheel drive feel".

As for what the transfer case can take, that is where you have to look at each of the shafts (input, front, and rear shafts) and see which one sees its limit first. It may not be the front shaft that is limiting. For that matter, it may not even be the shafts, it could be what the chain/gears can handle. This is where some engineer somewhere knows where the weak link is and what that value is. Can we find that tidbit of info?

 

The v8 f-type awd has the dynamic system from what it seems. I also found this link (that I don't really trust lol) from another post on the forums that would seem to indicate that the dynamic AWD system was fitted to XJs? I also was able to find an XJ presskit from 2013 that says the XJ AWD is predictive, although its only in Spanish for some reason.


Ill go look around in the f-type forum and see if any of the tuned ones happen to be AWD and what mods they did.

 

Bismark, this is what I was talking about with the car applying the brakes to individual wheels and limiting throttle response. That is the IDD system, or what most of us call the "Dynamic Stability System". You have a button for this system on your center console (looks like the car skidding out of control). This si similar to what other vehicles have except Jaguar is stating that theirs is predictive. This can really only be done by sensing as the wheel starts to speed up in relation to the other wheels. So, it is catching it a fraction of a second earlier than the wheel is truely loosing all traction. Through the application of the brakes, you are effectively transferring power front and rear, but in reality, you are sending the same amount of power to the wheels, just the brakes are sucking up part of it and making them hot.

 

That seems to be what I'm getting from the f-type fourms as well
Its a bummer that we will likely never see the kind of system I'm looking for with jag going electric.

Thank you for the replies though!

 

Bismark, do not be breaking hope quite yet. If you follow press releases and have a little bit of hope, you may get what you are after. There has been talk about making a new XJ, but it was going to be electric. But, as most know, that talk was ended. But, with the slowing of the market and people realizing we can't all drive SUV's there is word again about bringing back a saloon (not necessarily the XJ atleast in name). Whether electric or gas/petrol, who knows. So, not all hope is lost. Even if electric, that makes for an AWD setup that much easier. Tesla has a system in their Model S that is a 3 motor setup (one for each rear wheel, 1 for the front wheels). If anythign, electric cars make it a bit easier atleast from a mechanical setup. The electronics side, not so much. But, with the electronics, you would have more adaptability and more ability to tailor it to specifically what you want.

I would love to see Jaguar re-engage in talks with the new saloon. I love the looks of it. It would be one of a few bodies that I would contemplate geting electric.