Gasoline Grade - Page 2

Ok...let us/me know what you find

Well this is an incomplete reply, but the best I can do for now.

As far as I can tell the fuel is reformulated for winter to assist the suspension of condensed water in the atmosphere freezing in the tank. I can imagine there are some anti-waxing agents in there as well. Certainly the freezing of water or waxing of the fuel lines is bad news, and I can imagine if a vehicle isn't used very much, the water will collect at the low points in the system (i.e the tank and perhaps the lines below the floorpan) and freeze.

So my guess is that one piece of advice would be not to let your tank run down completely, in case the fuel pick up encounters collected ice (I have no experience to know whether this actually happens, but I do know that the tank pickup is at the lowest point, and usually involves a gauze type material to "wick" up the last of the fuel).

In really cold weather, the air density increases and so theoretically more oxygen enters the combustion chamber each cycle and you get more power. The automatic instinct is that more power = more potential for knock, so use a higher Octane fuel. However, in this wonderful world of ECU managed engines, knock sensors greatly reduce this risk. Also Jaguar use engine dynos to establish the knock limits and "map" all possible regions within the engine operating range; the eventual vehicle calibration is backed off to a safe limit away from this point.

One feature of lower Octane fuels is that there are less additives to combat knock, and by implication the fuel can burn under more marginal conditions. So under really cold conditions, a lower Octane fuel would help the engine start, and if you are only using the vehicle for short journeys, the faster warm up that may result would be a good thing. I can't imagine that the difference is large, but it may help long term carbon build up or injector clogging.

As an aside, my X type doesn't seem to have the air assisted fuel injectors that are used on the S type and the XJ (there is a passage for air which is blown tangentially onto the injector mist, helping the fuel atomisation process) , and I can imagine that their operating tolerance envelope is narrower. I discussed this with the local dealer and they confirmed that they had more injector problems with the X type than the others...

In conclusion, when I know that I'm only going to be trundling around the suburds of Detroit, I'll try 89 Octane this winter. When I know I'm heading out somewhere, I'll fill up with premium again.

Cool info..
You mention that the X type has more injector problems than the others....probably due to people not putting in the correct octane..?

I don't know about the fuel being a factor. The market in Detroit is different from the rest of the USA; almost everyone (including me) can get "employee discount" (4% below invoice), and the OEM managers get lease cars and free fuel.

One ramification of this is that there are a lot of Ford employees who get a Jaguar X type with free fuel, because they can.... These car drivers will not worry about the cost of fuel and will just put the high grade in. They seem to be especially popular as second cars, and during the week some of the malls seem like Jaguar factory car parks (Ford wives shopping club). So I suspect that the duty cycle these vehicles see is local shopping, and for the weekend trips its back to the Excursion and polluting the planet.

If misfuelling / ignorance is a factor, I would argue that this would equally apply to all Jaguars, and therefore the difference must be the hardware and perhaps the duty cycle.

I know some of the correspondants on this forum are from Canada; I'd be interested in their input.

Good point.

On another note, what have you heard about Ford/jag stopping production on the X-type? I heard that 07 is the last year due to low sales.

I went to trade mine in the other day for the new M3 BMW and they didn't want to waste their time looking at the X type, they said they couldn't sell it if they gave it away....or something like that.

Todd,

Using anything under 91 octane (that's "plus" in the U.S.) will shorten the life of many of the emissions control sensors. Just something to think about long term, I learned the hard way ($700 in sensors and labor, I just turned 60,000 miles).

I suppose it's kinda like bleeding the brakes.....
learn the hard way... ;-)

All good bro..

Wonder why they said they couldn't even sell a jag if they tried? What the guy meant was he couldn't put $5,000 on top of the sticker price and be able to tell the consumer where to go and how to shove it!!! :) My boss laughed at a bmw dealer when she found out how much they wanted for a bmw x5 suv! He said 950 a month or something like that and she did one of those sarcastic laugh in your face laughs and said your crazy. After that they knocked it down to 600 after she laughed! Needless to say she still didn't buy it! Instead she went and bought an Infinity!

Yeah i hear ya....I changed my mind after i told a few friends of mine what i was going to do....they all thought i was crazy in giving up my Jag....they all tell me the jag has more sex appeal and looks 100x's better....

can't argue there, i think they are right...

The 3 series to me are nice cars. I'm not necessarily a ford guy or gm guy or really anything like that. I drive what I like for the price I get and the looks it has. I'm a ford guy if it comes to trucks and perhaps suvs. I love gm cars but lately I can't say I like too many of their cars I used to like the monte's and the impala and bonneville but don't care for the g6's grand prixs. Also love the 3.8 liter engine but they are straying away from the engine I love. Anyways I wanted a 3 series bmw since the base on them is just below 30 grand. But when I shopped for cars and than found my wife was pregnant the jag was the only answer. I took many things into consideration when buying it though. Many people dogged on jags for the reliability of these cars but just looking at them and than factoring in abs, tcs, all-wheel drive, and jag factor I knew one of these cars would be mine once I found one that pleased me as far as price, look, mileage, color, model, and shape. I've had problems with the car but the overall google factor on this car is worth it! I take pride in every vehicle I have and try to take care of them the best I can. If its dirty I wash whether its going to rain or not!