After changing my gas to Shell 93 octane and re installing a K&N filter my gas mileage has jumped from 17 miles per gallon around town to 22 miles per gallon around town. This was a big jump so did the numbers twice and it came out the dame 22MPG.
Going to keep on checking it over the next couple of tank fulls to see if this was just a fluke or for real.

 

Adam, keep in mind that the X-Type's mileage is very seasonal. So, if you have suddenly had the temp go up, you can see a few MPG change. I would say to do another tankful and see what you have then.

I know on some of my longer trips, I could see the mileage change by a few MPG just because I fueled up at 1 brand vice another brand.

 

I never really noticed any difference with the mileage of this car due to seasonal changes, it seems to get 16mpg to 17mpg around the city since I purchased the car. As I said this 22mpg could be just a fluke, so as you suggested I am going to run another tankful of gas and see what the results are.
I have a app on my phone called Gas Buddy it gives give gas prices in the area in which you live. They mark Shell gas as top tier fuel. The explanation is top tier fuels have more essential additives then other brands of gas.. It is the only gas they show as top tier. Perhaps after using the Shell for awhile now, it has cleaned out the combustion chamber and other parts and the addition of the K&N filter which is supposed to make the car breathe better. But anyway I'll post what the next tankfuls mileage is.

 

Mine is an '03 3.0. I was getting 91 octane premium at the local grocery store discount station for several months, and averaging around 18 mpg (around town) Then I started getting the 93 octane ethanol free stuff from Gulf, as well as the 93 octane Shell. I am now averaging around 23 mpg. I don't think the seasonal change has made that much difference.

 

Consistent with my observations: Citgo gas (no alcohol) gets me 19.2 in the city, 27.9 on the highway over a known route, versus 16.9/23.1 on E10.

 

Adam, what brand gas and octane did you use before the Shell 93?

 

I'm Like Adam, 16 - 17 MPG is my average. Using Costco 91 octane, never tried 93 but I might just to see if it makes a difference.

 

Awesome guys..I always use Shell..Wish I could get it in 93 Octane around me..91 is all I can get....

Be advised; that a certain 'nobody' will soon be along to discredit all your findings...as irrational and fact less.

 

That's unusual. In addition to the engine running 'rich' during cold weather warm up, winter gas gets inherently worse mileage, an unfortunate but necessary evil. I see bigger swings in mileage than you just in comparing winter to summer.

To which factors do you attribute the sudden jump in mileage?

- higher octane

- going from E10 to pure gas

- different/better/more additives in the new gas

- new air filter

- different type of air filter

 

 

Before changing to Shell several months ago I always used Sunoco gas high test 91 or 92 I don't recall which contains ethanol. Shell 93 octane is advertised to contain nitrogen and no ethanol. I now wonder if the nitrogen is as good as it seems. But as I said this is the first time I have seen a increase in gas mileage since I owned this car so another tankful or two should verify if this gasoline is a good as it is said to be. Note Shell is always higher priced then other gasoline's.

 

I always used Sunoco high test. See my post below.

 

I was just using the 91 octane premium at the grocery store discount place or Walmart. I was getting around 17 -18 mpg around town, maybe 23 on the highway. Then I read something about ethanol free being better for your engine, and there was only one station in our area that sold it. It was Gulf 93 octane. So I started using it and noticed an immediate dramatic increase of 4- 6 mpg. But that Gulf station was out of the way, so I started stopping at the Shell, which had the 93 octane "V power -Nitro +". I'm not really sure if it's ethanol free, but it definitely was maintaining my improved mileage. Then once I had to fill up at a Marathon station at a convenient mart. Mileage immediately went back down to the 17 -18 range. I know some think this is BS -but I am a believer, at least when it comes to this Jaguar.

 

WOW!...10% to 11% improvement over Ethanoil...Again more proof that moonshine robs you of the mileage....Makes a difference in a lawnmower too

...wait for it....

 

I'm always curious about reports of huge mileage losses when switching to E10. Putting aside my own experience over several decades and that of anyone else I know where the loss is consistently about 3%, there's several aspects that don't quite add up when people claim 10% or greater loss.

- Ethanol has ~70% of the energy of gasoline. This is an easily proven fact. If a car was fueled with pure ethanol it should therefore see a 30% loss in mileage. There are virtually no cars around that run on pure ethanol, nor is there pure ethanol fuel to prove it unfortunately..

There are E85 compatible cars and E85 (85% ethanol, 15% gasoline) is commonly available. These cars see a reduction in mileage (again easily verifiable) of around 25% which supports the concept of ethanol having 70% of the energy of gasoline.

With E10, 90% of the fuel is pure gasoline. Easily proven. Even if ethanol has zero energy and just 'took up space', there's still the 90% gasoline. This means that a car operating on E10 cannot get worse than 90% of it's typical mileage while on pure gas.

If it were true that ethanol had less than 70% of gasoline's energy and actually had zero energy, an E85 car would only 15% of it's mileage while on pure gas.

- Putting science aside, let's accept the claims made above of up to 20% loss of mileage while on E10. If this was true and commonplace, where is the public outrage? People are fascinated with fuel consumption on their cars, far out of proportion to the actual dollar difference it makes in their wallet. Ask Joe Average on the street about erratic fuel mileage and he won't have any clue what you're talking about.

If Joe Average was seeing a 10 or 20% drop in mileage, it would be all over the 6 o'clock news. But it isn't. There would be a call for heads to roll in politics. But there isn't.

Just like all the sky-is-falling stories about cars being damaged by E10, where's the hundreds of thousands of cars broken down by the side of the road. I've been living with E10 for over 20 years. I haven't see one.

Carry on.....

 

"There are E85 compatible cars and E85 (85% ethanol, 15% gasoline) is commonly available."

Isn't E85 85% gasoline and 15% ethanol?

 

No, you had it right the first time, E85 = 85% Ethanoil/15% Gasoline.

They are not common around OK..maybe two stations in the entire city of OKC...Which is fine by me..

 

No. It's 85% ethanol as stated but what you assumed is quite common and part of the confusion and myths about ethanol fuels.

 

Is there an echo in here?..hello--hello--hello--hello

 

I don't know if ethanol (or the lack of it), is really the all encompassing factor here. My mileage only improved when I switched to the 93 octane. Not many stations even sell the 93 octane, and ones that do brag about all the special additives they put in to justify the higher price. (Nitro + for the Shell V-power/ Techron for the Chevron) Plus I think benefits of the higher octane (93 over 91), are probably unique to the higher compression/ higher performance type engines -like the Jag, BMW, etc. I ran a tank of the Gulf 93 "pure gas" through my wife's Hyundai and it made no difference whatsoever. I've not noticed the oil companies claiming their higher octane fuels will make you get better gas mileage, as they know it probably depends on what you drive and how you drive it. Their only claim is it's better for your engine -which has got to be really hard to prove. I don't believe E-10 is destroying engines either. But as far as public outrage making politicians heads roll, I think that is a bit overdramatic -especially if Joe Average is as clueless as you say. If some clueless Jaguar owner wants to think his car gets 10% better mileage with a certain fuel, and a couple other guys try it, and it works for them -I doubt it will make the 6 o.clock news, but let them revel in their ignorance.