Hello,

I am the original owner of a 2001 Jaguar Vanden Plas and would like to see what I can do to beef it up. I am def. inspired by this video: but I would prefer to keep the same engine block or (if I really really have to swap engines) use a Ford crate motor.

Things that I want to do include improving the exhaust note (more of a V8 growl), modifying the suspension so that the car is stiffer and does not roll as much, custom wheels and tires, adding sound deadening (there is a fair amount of road noise), potential swapping the engine for a ford crate motor (and transmission), or keeping the same engine but adding a supercharger and other performance upgrades.

I have heard that it is "not worth it" to try to modify the VDP and that purchasing a XJR as a base is a more economical idea. However, I just want to know what is possible esp. everything that is possible while keeping the same engine block (the soul of the car IMO).

For instance, would anything stop me from adding a supercharger to the existing 4.0 v8, replacing the transmission, and getting a new ECU / re-tuning the ECU? Are there any resources on this type of thing?

Thanks in advance!

 

At the risk of sounding like a stuck record - to add power is a non starter unless you have the kind of disposable income that car owner has on a project (50k) - you cannot add a supercharger as your engine has a higher compression ratio and it will melt pistons.

You want more noise but add sound deadening? Plenty of threads on how to add an X pipe by removing the centre box.

What you're talking about doing will be expensive if done correctly - and for a lot less you could find and buy a VDP supercharged, as Jaguar made them, effectively a long wheelbase R with focus on comfort.

I'll break it down
Engine and trans transplant - 20K+ plus electronic development...
Suspension and brakes - 5-10K and compromised.

It's easy to see how an R or VDP S/C is the fiscal choice.

 

Hey Sean,

Money isn't the issue here. As I mentioned in the OP, I have read about what is more expensive, I want to know what is possible.

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I want to add sound deadening (as mentioned in the OP) because there is a lot of road noise in the car.

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Does anyone know how much tolerance the x308 engine block has. If adding a supercharged to the engine is a problem because of the pistons then I can replace the pistons -- no problem.

Just curious: How much power are people able to get out of the VDP supercharged engine?

Please future replies: I am not concerned with what is the best bang for the buck.

 

If you want a stiffer suspension, you could swap in some XJR shocks, a few of the bushings on the XJR are stiffer (rear subframe A-frame bushings come to mind), it gets a rear sway bar which can bolt-in to the other x308 subframes, I don't remember if the springs themselves are stiffer.

If looking for more power while keeping in Jag engines, then an xjr engine/transmission swap is the place to start, since the transmissions in the N/A cars aren't really rated to handle much more power, while the R transmissions can take around 700hp. The next thing is to get a twin screw kit, which will increase power significantly. I haven't read too much on it, but I'd read into threads like this one https://www.jaguarforums.com/forum/p...xtra-hp-42059/ It looks like avos no longer makes the kits, so it may be a bit more DIY. You could also consider swapping in a 4.2 block and using some 4.0 XJR externals and electronics to gain a bit more power as well.

This is a good read for engine details (once i find the Engine Repair Course 168 pdf)

 

Only since you mentioned money being no object.

You'll never get the power out of the stock Jag blocks that you can get out of a traditional SBC or the like, dollar-for-dollar. However, you'll spend a good chunk doing the retrofit, and even more so if you want to do it and have it look good. I think I've seen somewhere about 650hp or so being the highest Jag-powered output, and I'm sure it was more than just a few dollars.

That said though, you're also going to have a completely different sound if you swap it out. There's a big difference in the sound qualities of the 4.0/4.2 than you get in an American V-8.

I think it might be helpful if you have an approximate goal in mind? Are you looking for a simple bump in output? say, 400-450? Do you want to throw 50k at a car simply to say you built the highest output XJ8 you could?

And I don't know why you seem so intent on keeping the same block that's in your car right now. Even going against advice that the XJR/Super V are preferable for power starting points, you could easily look into just swapping in the power train from one into yours, or the 4.2 that Nilanium mentioned. There's no justifiable reason to keep the same block that's in your car right now and trying to make it handle more, when it's going to be easier and cheaper to swap it over. And then you at least have a package that was designed properly to be the starting point for it.

 

You can probably get 1000HP or 100000HP but it's gonna cost plenty. Say what you will genuinely spend.

 

Thanks for the replies so far.

I agree - keeping the stock block would be stubborn. I just wanted to make sure it was not possible before dismissing it as an option.

It sounds like the way to go would be to source parts from an XJR as needed.

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CharlzO that is exactly the goal

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JagV8 I am not sure how much I will spend yet. I don't plan on starting the project this year and depending on what I will need to do, I could easily spend 50k over two or three years. This will def. be an ongoing project for me. Perhaps using the first year for the engine swap, the next for suspension, etc. The realities of the project and what parts I can source will dictate the build schedule. My entire thought process here is the following:
instead of buying a new car for 80K or whatever that will be worthless in 5 years, why don't I make my beloved Vanden Plas into something super unique and quick. Perhaps if I do the right things, the car will also retain some of the added value.


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Another question for the forum:

Is there any data on mating the supercharged x308 4.0L v8 with another transmission perhaps a 6G or 7G transmission such as this one: https://en.wikipedia.org/wiki/Merced...c_transmission

One more question:

Brake wise: what is the best people are able to do? I am sure we all have experienced the softening of the brakes after a few quick stops. Besides just upgrading the pads to EBC reds (link below, other suggestions are welcome) what other braking system improvements have been successfully underwent?

https://ebcbrakes.com/product/redstuff-brake-pads/

 

To clarify:

I don't expect a new transmission mating to be at all possible. I am just asking on the off chance that it has been done before.

 

If you're worried about road noise, don't forget to look into your tyres and replace any worn or misaligned door seals.

As for power, as everyone has said, an XJR is easier in every way, as it already has more power and better handling, as well as the better gearbox which can handle that power.. What is it about your VDP that you love so much? If it's the interior, you could always swap your interior into an XJR, rather than trying to swap the XJR running gear into your VDP.
The other option is to do an LS swap. It's been covered on here a couple of times, and would be a lot easier and more cost effective as it has been done before, rather than starting from scratch trying to get a Ford motor to talk to the dash and ECUs.

here's the link:
Jaguar Specialties

 

Hey Grandell,

I have an irrational hatred of Chevy, just one of those things haha. I'd prefer to break group on introducing the X308s to Ford DOHC Motors rather than doing an LS swap.

To answer your question about the VDP, one thing I like is the long wheel base. I guess there are supercharged VDPs though.

 

There are indeed. They are rare, and tend to be priced accordingly when they come up for sale, but they are out there.
I suggest you look very carefully into something like this, before you start down the path of retrofitting an engine that is in no way compatible with the cars electronics.

This reminds me of a piece of advice I was given long ago... If you want to make your car faster, buy a faster car.

 

How about buying a complete running XJR and swap engine/trans along with both ECU's and the instrument pack over to your VP. You'd still have your car along with more power.

 

The problem with going Ford vs GM, is that GM has been done, it's been researched, and the kit out there has already been built to adapt the LSx into the Jag while maintaining computer compatibility. That hasn't been done with the Ford. So while yes, you can physically do anything you want in regards to whatever motor, wallet-depending, there's a lot more to it than just making it fit. If you're in a location that will depend upon a computer to pass an inspection, you're setting yourself up for a LOT more money, time, and finding someone to research to make that connection work.