So, my understanding is that the difference between an XJ8 and an XJR is just the supercharger, and all the bits and pieces to go with it.

That, and I am sure some electronics may require changing to accommodate the new aspiration.

So, I am curious, has there been anyone who succesfully added the XJR supercharger to an XJ8 engine? What would I need to do if I were so crazy as to want to do the same thing?

 

That's a lot to convert, simply from the bypass button install to the intercooler. There are others with far more expertise about this on here. But it may probably be cheaper to trade yours for a SC'd one. That way you can drive it immediately and save the hassle.
Most older SC'd ones are about the same cost as nonSC'd ones.

 

Lower compression pistons, different valve timing, different transmission, etc.

It is much much easier to simply buy an xjr. That is what I did...well sort of. I "gave" my xj8 to my wife and bought myself an xjr

I just bought my pristine garage queen 2000 XJR with 55K pampered miles for $8,300 in the San Francisco Bay Area. It only has one door ding that will be easily removed. So the deals are out there.

 

You have to change a LOT. The XJR's supercharger/intercooler system is very complex, involving it's own complex coolant system. Many parts of the engine are different, including several cooling system components and a few other things. The XJ8 has variable cam timing, while the XJR does not. Also, the XJR has a MUCH stronger transmission, the 8's trans is probably not up to the task of the extra power. And then you get to the nightmare of the electronics. And then there's all the chassis differences, the R having a better suspension, bigger and better brakes, and a better final drive gear ratio. It would take an immense amount of effort to get to the same level that you'd start at with an R. You'd be much better off to sell your XJ8 and buy a nice XJR, because it will cost a hell of a lot more than the difference in cost to make the upgrades to your XJ8. The only reason I could see is if you wanted a Vanden Plas with the XJR underpinnings, but then you'd better served finding one of the Super VDP's, which is effectively that. Trying to supercharge the XJ8 is simply not worth the effort when XJR's are such a small amount more expensive.

 

Two fuel pumps in the tank and probably all new wiring harnesses, at least for the engine, transmission,fuse panels, different throttle body, ECU's...

 

I had no idea that the transmission also had to be changed.

So it seems the conversion is a No-Go, as I worried. Thanks guys!

 

I'll give you a finder's fee if you come across another deal like this!!!

 

What exactly are you looking for? year/color, etc?

 

I just bought a 2000 XJR with 84k miles, very good condition, for $7.3k. As Waterdragon said, deals are out there.

Dan

 

Well done!

Mine was advertised for $11,500, but had been listed for a while.

After some negotiating he ended up being happy with the $8,300 as he realized it wasn't going to fly off the shelf with multiple bidders.

 

I had the same question on my 2006 but noticed that you've already asked the question and now it's basically squashed....Were there any performance mods that you eventually did pursue to increase your power?