When first got the car tried various brands and grades of fuel. After many "experiments" settled on Sonoco 93/94 octane. At the next visit to the dealer for servicing shared this information with the service personel who looked at me in surprise because they had just got a notice from Jaguar (aka Ford) stating that this was the brand to use and the the correct octane level to use too. Wow, a consumer could actually figure out some thing that the company should have told me. In the ensuing six years, have used only this brand and level of octane for the car without any problems.

So what gasoline/petrol do others use and at what octane or am I "wasting" my money buying this relatively "expensive" fuel. Hard to challenge though the results.....thanks for any in put from the new guy "Bernie from Tenafly NJ."

 

I don't have any brand loyalty, just go for the lowest price I can conveniently find. I did, however, experiment with premium (93) vs. mid-grade, and although the 2005 XJ8L seemed to run fine on the cheaper mid-grade, I found the premium gave me 7% better mileage, at a 4% higher cost per gallon. So, the more expensive gas is cheaper!

Ray

 

Any chance of seeing this bulletin?

Here's what your owner's manual says:

"The preferred fuel should have an octane
rating of at least 95 RON (Research
Octane Number) and a minimum
anti-knock index (AKI) of 91.
Super Green Plus 98 RON unleaded fuel
(where available) may be used as an
alternative to the standard 95 RON
unleaded fuel."

Which is standard verbage for pretty much all Jaguars of the era. Preferred octane is 91 AKI, but 98 RON (93 AKI) can be used as an alternate. As discussed many many times before, there's no point in using higher octane than optimum/preferred as it's just wasted money with no return. Brand preference is not mentioned nor can I think of any reason that it would be. All known gas brands contain enough additives to get the job done.

 

Thanks for the reply...the bottom line here in the states is that 93/94 octane is the only realistic choice we have. As to the different brand's ingredients....Sonoco, according to the company notice had the (British term) "correct" elements versus the other four national brands tested. Also Sonoco did not change their formula based on the season as much as the other brands.

The dealer involved closed their place a few months ago, so getting a copy of the notice would be hard to do. Jaguar North American headquarters are located in Mawah NJ,only a few miles from my home....if you are ever in the area it is a great place to visit.Thanks again for response Bernie fromTenafly NJ.

 

91 octane is not available where you are???? That's strange. I can find no trace of any document issued by Jaguar that endorses Sunoco fuels.

 

I use 91 from Wawa and get 22 around town and 28 on the highway which from what I read, right on the mark.