I've just bought my Jag and this is the first of, I'm sure many "Newbie" questions. Is It alright to use regular gas or should I have filled It with premium grade? Thanks In advance for any help.

Submitted by vineyardman68@… on Fri, 03/28/2014 - 23:02

Hi Pal, welcome aboard.

A good time back when cars started being run by computers, I head that computers have the ability to adjust your cars engine based on what kind of fuel it scensed was being used.
When it comes to these things about cars, if it doesn't have an on and off and delete button, as to computers, I'm loss.
So one day a friend tried to clear it up for me. His explanation might be out in leff field, but to me it cleared things up for me.

He took a piece of paper and drew a long horz. line from one side of the paper to the next.
On the left side of the line he wrote LOW Octane and in the middle he wrote Mid Octane and on the right side about TWO inches from the end of the line, he wrote High Octane.
Above the line he wrote.Engines Computer.
He explained. The line represents the computers ability to adjust things in the engine. Low Octane is at the lower limits of the computers ability, The High Octane is getting close to the computers ability to adjust your cars engine at it's best.
He asked: where do you want the computer to operate in your car.
Not high tech, but it got the point accross.
If it says "PREMIUM FUEL ONLY" there has to be a reason.

Cheers

Submitted by SE21-30849 on Fri, 03/28/2014 - 10:52

Tommy,

I have a happy '04 X Type with 135K miiles on it, mostly put on it by my "clan". My experience is that in addition to not being beneficial for the car, lower octane will result in lower gas mileage. Therefore, ironically it may cost you more to run low octane gas than higher octane. For example, if you only gain 10% in gas mileage, paying 10% more for premium is a wash simply on mileage alone. That's what I've found even when playing with a blend of around 89-90 octane. Stay with 91+ and enjoy your kitty!

Submitted by stevejag@sbcgl… on Wed, 03/26/2014 - 20:13

Lots of opinions out there on this. As a long time Jaguar technician, I'll give you mine.

There are different grades of fuel for a reason. Engines and engine management systems are designed accordingly, to use [read: require] a given grade. Lots of science goes into that. Using a lower grade than what's specified in today's engines is not a real problem in the short run, but is not good on the engine in the long run. Performance and fuel economy will noticeably suffer, and frankly a 2.5L X-Type needs all the performance it can muster.

From an expense standpoint, I have always felt that the cost difference between the lowest regular and the premium grades was a bit over-blown. Let's take your X-Type; you have 15 gals usable fuel in a 16 gal tank, give or take. Figuring a twenty cent difference between lowest and highest grade, that's three dollars per tank more for the premium. I feel if I can't spring for three dollars a tank for what is best for my car, I guess I shouldn't drive a Jaguar. But that's my opinion.

Others will chime in. Whatever you decide to do, enjoy your 'new' Jaguar, and consider joining your local Jaguar Club. You will meet some great people!

Cheers,