The book calls for 91 AKI and it seems Euro 95 can meet spec. What is the consensus though - 95 or 98?

 

Euro 95, or 95 RON, is just fine. The Anti-Knock Index (AKI) is used in the U.S. instead of the RON, and it is the average of the MON and RON.

 

JImgoose: Thanks, it makes a difference in the wallet here in Belgium. Book is a bit vague on oil. 0w-30 or 5w-30 in your opinion? Natural or synthetic?

 

That's one of those Religious War questions! Personally, I use Castrol 5W30 semi-synth.

 

That's what I use in the Hotrod (BMW 335i). Happy knowing that; don't want to cause another Crusade!

 

+1.

Seems strange that an EU owners manual specifies octane level in AKI (a rating system used pretty much only in North America) and North American owners manuals specifies octane levels only in RON (used everywhere EXCEPT North America).

As to which oil to use, follow the viscosity recommendations found in the manual. Whether you choose conventional or synthetic or a blend usually comes down to what makes YOU happiest, the car couldn't care less.

 

95 is fine. Belgium gets quite cold at times (I think - may be wrong) so maybe 0w30 but otherwise 5w30. Any oil you like, the car doesn't care

My handbook (UK) specifies 95RON. Says 98 can be used, which I think just promises nothing dire will occur (slight wallet damage).

 

My handbook (USA) says S-type fuel should be at least 95 RON, but that 98 RON may also be used.

I take that to mean that anything less than 95 RON could lead to undesirable consequences, and anything higher than 95 RON could lead to even better performance.

If performance is of no consequence, then whatever...

 

But not one bit of evidence has ever been provided that it does, so as per your recent advice to me, let it go......................

 

There's an old saying that if you throw a stone into a pen full of pigs, the one that squeals is the one that was hit. Seems true after all.

Maybe we ask Jaguar if they had any "credible" evidence before issuing a manual with unsupported information.