Alright, So I've been trying to find the answer to this question but cant seem to get one. I'm looking to swap out my blown 2010 XF 4.2 Engine with a Running 2010 Supercharged 4.2 Engine. I know this isn't the easiest job, however I feel like its more then capable of being done. I also understand ill need maybe an additional water pump and some electrical mods, but my main question is regarding the Engine Bay Wiring Harness. I know ill need to replace mine with the SC ones. However; I need to know A) are they compatible? I don't see why they wouldn't fit but of course need to be sure. B) would it have to be the specific year? ie 2010 or will 09-12 SC wiring work too since the model is the same. and C) if my Base 2010 can be wired up with the SC Harness, What else will I need to replace? ECU? please remember the only thing I'm really changing is the Supercharged option. Still 4.2

 

Not sure if it's technically possible to do, e.g. just swap to 4.2SC ECU etc, but 1) consider all the other parts that are different on the SC model (on the 5.0, it comes with a different transmission, for example), not to mention brakes, suspension, etc 2) even all that aside, make sure you do the sums properly. These cars are getting older and cheaper by the year, so see how much it would be to sell or (if you have the time/space) part out your blown 4.2 and just buy a 4.2SC or even a 5.0SC, compared to the time, money, and effort the swap would take, with no guarantees of success.

Every marque of car I've owned, the forum always, always has regular questions around swapping a powerful model's engine into a less powerful model, and the answer has been and is that it's always, always quicker, cheaper, and easier to just buy the car with the engine you want. I know it's not what people want to hear but in nearly all cases it's the truth.

 

Also note there isn't a 2010 4.2 SC. In 2010 the supercharged models got the new 5.0 V8 and the base had the old 4.2. So you'd need to find a 2009 XFR for the 4.2 SC. If it's running at that point you'd be better off just buying a 2009 XFR and sticking with that.

 

Older and cheaper - yeh right - the 4.2 supercharged is not a common engine and comes at a price - so buying a complete car ironically may be the cheaper option but the challenge then is that they have been in the hands of those that really couldn't afford to maintain them appropriately.

I'm afraid I concur having spent a lifetime messing with cars - over 40 years - and I too had all those dreams of power - but if you want a car with a supercharger - buy a car with a supercharger - can't afford a car with a supercharger you certainly can't afford to build one.