OK!!!


But, summer vs winter blend in Ca is used as an excuse for higher prices. Ca refinery production goes down. Oil co's alledge they can nt import fuel as it isn't CA approved.


Around here, temp spread is not enough to need different fuels. Low 30's to 100.


But, true in other areas. Death Valley and other places at 120. High Sierras down to the teens.


Off to other stuff.


Carl

 

I don't think I'm confused at all. You misunderstood my reply unfortunately.
Instead, I'll try asking the Jag engineer. Among all the conflicting information I'm sure they can shine more light on this subject.

 

Not quite sure what 'Jaguar engineer' you're going to talk to. If it's mechanic at a dealership or an independent, they may be as misinformed as anybody else. If they don't understand and can't explain the huge difference between detonation and pre-ignition or use the terms interchangeably, you'll probably come away with the wrong and confusing answer again.

Your points of "it loses power and gets weak gas consumption", "thus the engine feels sluggish, loses power and spends more fuel than necessary to keep up" and " The engine stays cooler with less excessive combustion" (direct quotes so there's no misunderstanding) are all characteristics of pre-ignition, not detonation and are therefore unrelated to octane levels. "Oil pressure stays higher in 80 degree sun" has no relation to either.

As others have said simply have a look at what's written in your owner's manual.