Picking up my new 04 Crossfire limited on Saturday. Have heard from many that the middle grade of gas is okay to use from a quality station ie..Chevron, Shell, etc. instead of the recommended premium. Any advice???

 

Heck you can use regular unleaded from Sinclair (big green dinosaur!) but the ECU will readjust and you'll end up with reduced performance and probably lower gas mileage too.

Moral is spend the extra $.25 / gallon and enjoy trouble free performance for years to come...

I can only get 91 but if I could get 93 I'd gladly pay more for it!


PS there's a reason inside the gas door it says premium fuel only.... (at least I think it says that inside the gas door).

 

Yeah if the warrenty people find out why your valves are shot save 15 cents ,...

 

I would have said yes until yesterday when one of my cat convertors have gone. I'm just wondering if lower grade fuel has caused this??

 

Saldous I'm guessing you are using the 95ron, not 98 super unleaded in the states i think middle grade is 95? it goes lower i think to 91??

 

Lower grade fuel can cause that. I know someone with a Mercedes SUV and his wife used 87 Octane and after a while (maybe a year?) they had to replace the catalytic converters.
So, DO NOT use anything other than 91 or higher octane fuel, unless you enjoy engine damage from preignition. This isn't a 4 cylinder Honda Civic.

 

I will have to agree and yes, the gas door does says "premium fuel only". Yeah, I had to go look too.

 

Yes I use 95 and on rare occasions 98.

 

don't even know where you could get 91 in the uk?

 

Nor me. I didn't realise 91 existed!

 

UK octane rating <> US octane rating

Snip-it
Jaguar V12
Fuel Requirements
Just determining what fuel is recommended for use in the Jaguar V12 engine is a bit of a challenge. For example, in the XJ-S H.E. Handbook for the US-spec 1983 model year, on page 111 it merely lists a "Recommended minimum octane rating" of 91 (RON) Lead Free. Many people have read this and concluded that the car calls for Premium, since the typical octane ratings in the U.S. are 87/89/91+ -- but that's because they fail to notice the reference to RON. US gasolines are not rated in RON; they are rated in the average of RON and MON, commonly marked on the pump as (R+M)/2. Unless you know how to convert RON to (R+M)/2, the spec in that handbook is meaningless.

Apparently, Jaguar improved their handbooks later. Douglas Dahl says, "It states for my '89 H.E. with Lucas ignition 'In the United States, Federal Law requires that gasoline octane ratings be posted on the pumps. The octane rating shown is an average of Research Octane Number (RON) and Motor Octane Number (MON). This number is also referred to as the anti-knock index (AKI) or Average Octane Number (AON).

"'Unleaded gasoline is available in two grades; 'Regular' labelled at the pumps as 87 AKI (91 RON) and 'Premium' labelled at the pumps as 91 AKI (95 RON). Use unleaded gasoline with an octane rating of 91 RON, i.e. Regular fuel.'" Apparently Jaguar was unaware of the availability of mid-grade 89 octane fuels.
End Snip-it

Here's the web link

Here's the summary:
US 87 = UK 91 RON
US 89 = UK 93 RON
US 91 = UK 95 RON
I would guess that US 93 = 97 or 98 RON

 

Hmm, in Maryland, the highest I see is 93...where is this 95/98 octane baloney that people are sprouting? Or is Maryland simply not good enough for quality gasoline?

 

ummm look at post #11 it's right above your post...

 

could baloney in your tank possibly be the cause of the "Acrid smell at high speed/RPM" you were experiencing?

sorry, couldn't resist.

 

Not if its first name is O S C A R and its last name is M A Y E R

LOL!

 

lordpercy and saldous,

I believe that the methods for determining octane rating is the US is different from the UK, and I don't think they are comparable.

(whoops ... pardon me ... I should have read the entire thread before I responded)

 

I just buy Premium 91 here I've never seen 93 in Calif. I always put in 91.
Gas is the cheapest thing you can buy for your car.besides water.

 

Actually gas is cheaper than (bottled) water, in a very general sense and according to John Stossel, adjusted for inflation gas has never been cheaper!



Edit: BTW, its 2005, where are the flying cars?

 

I guess I'll start drinking 91 proof .

 

We get 98 octane down under