Apologies in advance if the topic was already directly discussed, but I found no search results.

What is different about the 2014-2015 V8 R 550HP motor compared to the V8 S 495HP motor to account for the +55HP? Anything mechanical or internal? Boost? The ECU tune?

Thanks

 

100% ECU tune.
There are some views that the 495 PS quoted for the S was understated and it was quite possibly really 510 PS as per the XFR/XKR/XJR of the same vintage.

 

Thanks. I was curious when I saw Jaguar's 2014 and 2015 catalog that really didn't mention anything substantial an their "dyno" graph looks a little too suspiciously flat for the the S vs R:

 

according to the specs there is more boost in the R (1.7 bar) vs S (1.5 bar) models.

 

Thanks for that info Harris.

In the meantime, I reached out to Velocity AP, as I noticed their ECU tuner is advertised as boosting the 495/510/550/575hp 5L V8s to 605hp. They claim the engines are mechanically the same, and it is the ECU tune accounts for the various hp ratings.

 

VAP is correct. The only difference between those variants is the tune.

 

You know what that means for me . . .