See here: https://www.racechip-usa.com/chiptun...essor-R-375kw/

Has anyone fitted or tested one of these?

If so, does it work?

It seems a much cheaper alternative to getting an ECU tune done, and where I am in Adelaide South Australia I don't know anyone who is willing and able to tune the XFR ECU anyway.

When I had an XFS I bought and fitted the diesel version of the RaceChip tuning chip, a RaceChip Pro2.

It worked quite well and gave significant and noticeable increases in power, torque and throttle response.

It simply plugged into the fuel rail control electrical plug, so all it really adjusted was the fuelling.

I assume the 5.0 S/C version plugs in and works in much the same way, but so far I have been unable to find any info about how it works and what is involved in fitting it.

Seems too cheap to me... It's a piggyback ECU?

Just a flash-tune (the one's that are known to deliver their claims) will set you back around double the price these guys quote on their website.

So I have my doubts...

Cambo,

Yep, it appears to be a type of piggyback ECU.
And that price from their US site is 2/3 the price of the same thing from their Euro site, go figure!

I dont recommend RaceChip. Those chips are made only by rewriting the maps, moving sliders there and back hoping for the best result and this for each car. If you want extra power and torque for your XFR I recommend to load XFR-S ECU, I have it loaded up for some time and it works great. Only thing is you need original diagnostics SDD (downloadable) and Mongoose Pro cable and we can do it online thru teamviewer. This original software is made and tested by Jaguar, gives 570 hp (EURO 5) and near 600 without cats and xpipe installed. All tested, works great. More info - PM

I had a racechip pro2 fitted on my previous lexus is220d and it made an instant difference all round. i eventually got the mpg to 44.4 almost unheard of in the 220d so it worked for me. anecdotal evidence is really no evidence at all but i and my pocket, felt that it worked.
I contacted the company in germany when i got my current 2.7 xf diesel as they state that when you change your car they will recalibrate the box for your new model. unfortunately they didn't have the software to convert from lexus to jag, so i bought a different box, a bluespark something or other for about £140.00 and fitted it. A real scunner of a job getting the original plug from the fuel rail, but several scraped knuckles later it was on and im now doing over 35 per gallon with this increasing. the diesel xf feels sharper and more torque so no longer do i have my heart in my mouth at roundabouts and junctions.
Anyway, what i'm trying to say is that for me, the box works and works very well.

Tuning a diesel is very different to tuning a petrol engine. No doubt they work fine on the diesels, it's far less complicated.

Do you still have this available