Please let me know if the following is correct. The XFR is rated from the factory at 510hp. The XFRS, 550. The only differences between the two with regards to power, is the exhaust, and ECU tune. It's been said that the XFRS tune will not work properly on a stock XFR due to the exhaust differences. So, it seems to me, if you add an X-pipe exhaust alone, you should be able to reliably flash the stock XFRS ECU tune to an XFR and expect the same 550hp rating. Further, aftermarket tuners tune the XFRS as well, and from what I've seen, these are different tunes from the XFR tunes. If one has an XFR with the updated X-pipe exhaust, wouldn't it be reasonable to expect the same end result as an XFRS going with an aftermarket tune? Should one simply request the XFRS tune for the XFR with exhaust at that point?

 

1. It's 510 PS vs 550 PS, or 503 bhp vs 542 bhp.
2. Yes, the only differences are the tune & the X pipe in the exhaust.
3. The XFR-S tune cannot be put on a pre-2013 XFR because they use different ECUs, Denso vs Bosch. The workaround for a pre-2013 XFR is to put the XKR-S tune (identical to the XFR-S tune) on instead, as both use the Denso ECU.
4. You can't get the factory XFR-S tune or XKR-S tune from just anyone, only someone with "special" access will have it, and even then it can only be installed using the proper SDD equipment. No JLR dealer can or will do it.
5. These days you are better off going with an after-market tuner, plenty out there, and apparently it is no longer necessary to fit an X (or H) pipe for the tune to "stick", although in theory it will release a few more horses.

 

Hey sorry for a late reply to this but is there any chance you think that having a flex fuel option could be a reason why some vehicles can’t accept other tunes? I’ve learned that 2014+ have options from the factory to utilize E85/ Flex Fuel which essentially could increase power output as well as answer the question as to why the XFR-S tune won’t work on an earlier model. I am aware of the difference of the Bosch and the Denso. Unfortunately I have a Denso (2011) which is very limiting apparently. Anyways. Just some food for thought.