I have wanting to turbocharge my S-Type for a while now and i was wondering what all i would have to replace in my engine and ECU to have it run properly without fear of blowing a cylinder.

 

It's a high compression engine. Do you mind if you wreck it? Oh - you do. Not a good move, then.

I don't think anyone at all tunes the 4.0's PCM (old tech, plus no demand anyway).

Sell and buy another car, maybe an STR.

 

Its easier to do than you think...i've installed a turbo on a high compression engine and it worked great. Its all about cooling and not going mad with the psi. I installed a piggy bank engine management (smt6 I think it was called) a 5th and sixth injector ( was a 16v 4 cyln.engine), intercooler and methanol injection...you have to upgrade your fuel pump and i.stall an aftermarket fuel pressure regulator to boost fuel pressure on demand and stop you going lean...there's a lot of work to do, but its all doable....but like jagv8 said, sometimes its just easier to buy a ready turbo car...up to you!

 

As these cars don't have a fuel regulator or fuel return it'll be more work still.

Be sure to upgrade the chain tensioners in any case or you're on borrowed time.