Is it best to get up to speed quickly (30 mph say) and then ease of the gas to keep it there or slowly get up to speed ?

The same question for 70+ mph

The reason i ask is getting up to speed with little gas seems to make the actual mpg readout show about 10-15mpg for quite a while whle getting up to speed then ,30mpg+/- whereas lots of gas shows 5-10mpg for a very short time then 30mpg +/-

Which way is better ?

Thanks

P.S. Happy New Year

 

[QUOTE=police666;448123]Is it best to get up to speed quickly (30 mph say) and then ease of the gas to keep it there or slowly get up to speed ?

The same question for 70+ mph

The reason i ask is getting up to speed with little gas seems to make the actual mpg readout show about 10-15mpg for quite a while whle getting up to speed then ,30mpg+/- whereas lots of gas shows 5-10mpg for a very short time then 30mpg +/-

Which way is better ?

Thanks

P.S. Happy New Year :

I try not to think about it because the 4.0 engine in mine can pass everything but a gas station.

 

I don't know the answer but when I need to get good fuel mileage I drive my 1982 VW Rabbit Diesel. When I drive either of my Jaguars, I sometimes drive like a complete idiot because I can.

The worst mileage is the 1988 Chevy farm truck (10MPG) but it gets the job done.

The best mileage I get is when I 'test drive' a customer car to the bank 4 miles away.
I get to the bank and they get a confirmation of the work performed.

bob gauff

 

Jaguar =/= Fuel economy.....

 

I use my bicycle for work - I get excellent gas consumption! Oh, and I get some exercise. I guess I'm lucky!

 

Hi Police 666, Its best to accelerate moderately to the desired speed, then back off on the throttle to maintain it. Your observations of the instant MPG readings are correct. Attached is an article I wrote and have previously posted for members who are interested in improving their fuel economy. I have a lifetime fuel economy of over 28mpg with a best tank fill of over 36 mpg in my 2000 3L SE. Modern Jaguars can deliver good fuel economy if driven well.

SimoCat, great ! I used to ride my bike to work often and still do for exercise and errands where I'm not in a hurry or have to carry much. I also ride my motorcycles a lot when the weather allows.
all the best and happy New Year VMV

 

There have been many heated discussion about this over the years....sorta like oil, spark plugs, and premium fuel :-). We can read about pumping losses and volumetric efficiencies and the dynamics of air flow and the coefficient of linear expansion and...and...and...


I can't get my head around some of that stuff. No college education :-)


But.....


Every now and then I get a bug to do a "MPG" check or "Economy run" and absolutely without fail I get best results when I drive as though an egg was under the throttle pedal and just *gently ease my way up* to the desired cruising speed.

"Your mileage may vary" :-)

Cheers
DD

 

VMV hit the nail on the head...get throught he gears on moderate throttle than back off at 55 mph. Engage cruise control.

 

Cruise control will also accelerate moderately, when the resume button's pressed. But I'm dubious about CC's ability to deliver better fuel economy than a careful driver who maintains the same speed. CC can't anticipate the steepness of an approaching gradient, & has to kick down through the gears to maintain speed. Whereas a driver can see the hill coming, & feed in a little more gas to maintain speed, without the need of a kick down. What do others think?

 

Concur, but avoid too much thinking in the process....just drive while having fun.

 

I think that the way to get best mileage is to get up to speed quickly without overrevving. Get into the highest gear possible as quickly as possible.

Don't hold your foot to the floor.

On surface streets it does little good to break the speed limit too much as you will probably have to stand on the brakes.

On the freeways, get up to cruising speed and hold it there, using cruise control. Do not stay in the left lane if someone faster wants to pass. If you do, he will use the gas you save by accelerating to get around you.

 

I always get best results using cruise control. Guess it depends on how steady your foot is :-)

You're right about hills, though. On the occassions that I'm trying for max econonmy....a bit rare, really....I click the cc off on the hills.

Cheers
DD

 

Which generally means using the smallest amount of throttle possible. Under minimum throttle and minimal load the trans shifts earlier.

Cheers
DD

 

I think, and I'm being honest here, that I could care less about my fuel economy. I didn't buy this car to worry about gas mileage or to drive it like an 80 year old blind woman. I dig into the throttle a bit and take it to about 3500-4000 rpm in each gear under 1/2-3/4 throttle, after she's warmed up of course. I don't floor it and redline every gear, I've only taken her to 6000 rpm maybe three or four times last year, but I drive the way these cars were meant to be driven. With spirit.

Just my .02

 

It's not just acceleration, but how you brake too.

For best fuel consumption, you have to drive like the car has no brakes at all.

 

ok, thanks everyone that posted, normaly fuel usage does not bother me, i normaly average 8-12 mpg (all rush hour and "fun" driving).

But when i pick my kids up i do a 400 mile round trip and would love to do it on 1 tank.

Here is the route i take, (a483) it's nearly all country roads with 60mph speed limit.

Liverpool, Merseyside, UK to Swansea, UK - Google Maps

 

I'm not sure the doable MPG of the 4.0+5R55N would manage 400 but the STR might so maybe the 4.0 can. You'd really really have to cruise at say 55/60 (say 60 on speedo as it'll overread) and stay off the brakes and throttle. In case you need to keep slowing for villages etc then I reckon that would ruin the chances.

 

Nor did I :-)

But I sorta doubt that anyone here is "worried" about fuel economy but that doesn't mean it's totally forgotten, either.

For some owners...especially those where the Jag is the only car and who drive, oh, 1500 miles each month.... fuel economy can indeed become a significant part of the overall operating expense.

As for me, I like to do an accurate check every so often. I know what sort of economy I should be getting. If it suddenly drops, I know there's problem that needs attention.

Cheers
DD

 

Hmmm tricky, carry a syphoning kit. = generally most economical.

But, if he ignored the fuel gauge, computer, and warning lights etc, would the car physically make it before running dry?

I know that the S Type fuel tank is relatively small compared to the 90l in the old XJ40, and this topic is a bit 'how long is a piece of string', but still even after all the myriad threads on this subject.

What is the max range of a petrol 4.0 S Type when driven with a foot that Cinderella would be proud of?

 

I just got £91 in my tank @ £1.29 per liter. so thats 70.5 liters, the needle was resting on its stopper and the range said 4 miles.

Thats 15.51 UK Gallons

Thats 18.62 US Gallons

I thought the S-Type tank was 18 gallons UK, so did i have 2.5 gallons left in on empty or is it 18 US gallons and the half a gallon was what i squeezed in the tube/filler neck