PeterT said:You're probably referring to the XU9JAZ. My Xantia has the XU10J2 which definitely has a knock sensor. With 10.4:1 it definitely needs 95 RON minimum (as stated on the sticker under the bonnet) and pings on 91.
Even being an auto, it regularly returns 41 mpg at a steady 110 km/h when using 98 RON.
Interesting, I'm going to have a search and see if I can find a knock sender on it (my reasoning being, why are you guys getting pinging if there's a knock sensor ).
Either way, I'm going to average the next few tanks of ULP (I've never heard it ping), then run a few tanks of Optimax to see if I can find a difference.
seeya,
Shane L.