I did a search and didn't find a thread on it. But are there ways to tune the N/A engine? Meaning the one which came in the XK8. I have read about exchanging pulleys and other things with the XKR supercharged engine. But I didn't see anything about increasing power with the XK8.

I know Aston used a version of the AJ-V8 engine for the V8 Vantage which went from 4.3 till 4.7 and they made 380bhp and 420bhp respectively without a supercharger or turbo. Even the 4.3 made considerably more power then the 4.2, with a mere 0,01 increase in displacement. Not sure exactly what Aston did. But are there available options to tune the AJ-V8 N/A to produce more power?

 

Short answer no. Long answer, it's possible, however, buying an XKR and upgrading that is more cost-effective. Even if you have deep pockets, it doesn't make much sense.

Adding any kind of forced induction to the XK8 would require changing or reinforcing major components like the pistons if you want any sort of reliability. On top of that, a chip and tune on the Jaguar ECU is next to imposible, and even if you did do one, without any other tuning, it would be pointless. You could, theoretically, gain a few horses with exhaust and intake upgrades, but you may just be shifting the power and torque bands if not done properly. You could try increasing the bore, among other things, but this is expensive.

The Aston engines are completely reworked, with many many components made bespoke for the Astons, and most components are not direct fit onto the Jag AJ engines. Thus, they may require extensive modifications to be made compatible.

So, if you are already contemplating you need more power, buy the XKR, then, if you still lust for more power, swap the supercharger for a Twin Screw unit if you want 600 ponies. If you do end up with an XK8 and want more power without buying a new car, you could always LS swap, which some people frown upon.

 

You do, however, have more luck when it comes to handling modifications. You can install a Quaife LSD, upgrade to polyurethane bushings, you can buy stiffer or lowered springs from Adamesh and Paragon. I think it is not too hard to find aftermarket shocks and upgraded brakes or even go custom made. You could also put the Jag on a diet (and sacrifice luxury), by stripping the interior, among other things.

This guy supercharged his XK8 and did a write up:
https://www.jaguarforums.com/forum/x...ed-xk8-127904/

Here is a discussion about swapping a manual transmission:
https://www.jaguarforums.com/forum/x...to-xk8-114140/

This guy also sought to do performance enhancements to his XK8:
https://www.jaguarforums.com/forum/x...ormance-57035/

XK8 exhaust mods:
https://www.jaguarforums.com/forum/x...estions-96122/

The Reverend also wanted to mod his XK8 a few years ago.
https://www.jaguarforums.com/forum/x...e-power-37610/

As far as I know, only Tony has done major upgrades to an XK8/R. I'm not sure which one he is running. He's a member here, but I forgot his username. If you contact him he can properly guide you. He basically makes project cars for a living and is exceedingly knowledgeable of these Jags.
http://www.paragondesignuk.com/xkproject.htm

 

Giandanielxk8, always you man. Always you. Thanks!

I was not really thinking about forcing induction but rather keeping it N/A. Otherwise I would think a XKR engine transplant would be easier?


Ok. So probably cheaper finding an used V8 Vantage engine and dropping it in a XK8 it seems. Should fit right?

Yes, including me. Wouldn't have a Jaguar with a Chevy engine.

 

Not a case of not wanting to buy a XKR. I'm just researching in case the right car that pops up is a XK8. It's looking to me I won't have my pick of the litter here. I may have to just buy the best X100 I can find, regardless if XK8 or XKR. Unless I want to wait for a long time or pay through my nose to the crazy people asking 30K + for a X100.

I would be fine with a XKR oh yes. Although I do prefer the sound of N/A engines though. But XKR would be great anyhow.

 

It's probable that the Aston engines fit. Now, would you have to fabricate custom engine mounts? There's also the question of if the electrics would play nice between the Jag stuff and the Aston stuff. You would be treading into uncharted waters. An XKR engine transplant (with transmission as well) is easier and has been done.

Have you considered buying an XKR and having it imported from across the pond? It may even be cheaper. BTW, I edited post #3 and added a few links worth reading regarding XK8 performance mods.

 

Thanks for the links. I will check them out.

 

About the Aston engine, I would think this would be prohibitively expensive. Although instead of dropping a LS1 engine in it to get a manual transmission like some do, maybe dropping the V8 Vantage whole drive train would not cost much more and be much cooler. The Vantage had a manual option. But it was a transaxle set up. So some major modifications would need to take place. Or just use another conventional gearbox. As for engine mounts, maybe they are even the same? If the outter shell is the same. But I don't think the mounts would be the sticking point. Cost of something like this is what would be the road block if I would have to guess. Aston started from the AJ-V8 and many parts are still the same. So probably could be made to work even easier than a LS1. The electrics could be solved with a good stand alone ECU maybe? Isn't this what LS1 swaps do?

Buying an U.S. X100 car is something that has crossed my mind. But this would be my last alternative, as it would mean buying a car sight unseen.

 

A search within XKRACER may return some of what you are looking for.
A good start maybe taking a look at his signature pic and his website. Click here

 

Thanks!