THE INTERNATIONAL JAGUAR 'S'-TYPE REGISTER FORUM

Our Sasol fuel that is supplied to the entire highveld region can contain up to 12% heavy alcohols, that come off of their coal gasification process, can be a menace. I bought milky clear nylon fuel line from the US as being "the right stuff" & suitable for E85 & California etc. ethanol areas. Well the Sasol fuel destroyed it in about a week. So I threw authenticity out of the window & went for practicality. Cursed stuff gave me a real headache.


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I use super unleaded as standard unleaded gives my engine the runs. Sorry run on as when I rebuilt my engine I put the higher ratio 9:1 pistons in after the rebore. I could switch the ignition off get out of the car, open the boot and set my chairs up before the engine would eventually stop chugging and die on the regular stuff. Super unleaded stopped that for me.

Our standard 93 octane contains 5% ethanol - not good for our cars fuel system and lower mpg.

I have always used 87 octane Regular Unleaded, in both cars, no pinging.

gas is $2.29 - $2.49 over here..More expensive in California and other Western states.

[quote=NigelW post_id=2591 time=1552588690 user_id=52]
I reckon you'll have to fill up before you get to Coventry to be on the safe side as you will consume more gas on the motorways with the higher speed. I only use super unleaded and that costs £1.32 at my local BP station. In the "olden days" if you did a constant 100 mph you could see the fuel guage dropping before your eyes.
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We will see in June how far I get. I have seen the gauge dropping on a trip down the motorway. With the one 7 gallon tank on the gauge at a time, it is more obvious than having one gauge on a 14 gallon tank.

I reckon you'll have to fill up before you get to Coventry to be on the safe side as you will consume more gas on the motorways with the higher speed. I only use super unleaded and that costs £1.32 at my local BP station. In the "olden days" if you did a constant 100 mph you could see the fuel guage dropping before your eyes.

[quote=NigelW post_id=2584 time=1552584208 user_id=52]
It costs £150 to fill up my XJ with super unleaded.
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I have never filled up the S Type to capacity but working on an average price of £1.25 per litre for Unleaded X 14 gallons X 4.55 that means about £79.60 to fill to the brim and that should get me 252 miles at 18 to the gallon. In the UK that's like driving halfway to the moon. When I go to Coventry in June I will be able to test out my theory because that's 200 miles each way for me.

In the US you can buy an old Jag for about the cost of a tank of gas so people are not inclined to look after them.

1984 XJ6 fuel capacity = 23.5 U.S. gallons or 19.6 imperial gallons.

S type has two 7 imperial gallon tanks or 8.25 U.S. gallon tanks. Thus capacity = 17.5 USG or 14 imperial gallons.

That means the S Type is only doing 12.85 miles per USG ~ something is wrong ~ heavy foot (comparing apples with pears), tired or out of tune engine etc.

The fact remains that captive breathers are bad news.

It costs £150 to fill up my XJ with super unleaded.

[quote=Jose post_id=2582 time=1552576451 user_id=62]
I get 525 miles on the highway out of its twin tanks before needing to refuel, doing 72 mph with a/c running. The distance between Florida and Tennessee is around 830 miles, so I refill once and then have plenty fuel left when I arrive.

The S type only goes 225 miles by comparison.
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Difference there Jose is the Xj6 has two 12 gallon tanks compared to the S Type which has two 7 gallon tanks so a difference of 10 gallons in capacity.
Your XJ6 is doing 21 mpg and the S type is doing 16 mpg by your calculations but more fuel lets you go further before you have to refill. In the USA it probably costs you $5 to fill up. In the UK that would be £90 that's $120 to fill the S Type.
Official figures have the XJ6 at 17 mpg and the S Type at 18 mpg.