Got Me An Is250 Sel-Mm!

[bluenose1940]

At last it's happened, I now have my IS250!

Got me an absolutely superb deal too. Beautiful colour, Cambridge Blue I think it is, with Sussex Grey leather. Must check out those details to be sure.

I have just picked it up from Lexus Plymouth, drove it home which is about 50 miles, on the A38, the B3176 and a few side roads, drove at spot on the speed limit on all roads (pretty much all the way) and usng cruise control and, the trip computer was showing 47.7mpg as i drove onto my driveway. It will be interesting to see how it averages out overall.

When i pulled up at the first set of traffic lights I thought oh b***** hell I've stalled it, but a quick glance at the tacho showed me it was still ticking over nicely, couldn't hear a thing from the engine! That was the case every time I stopped so I will no doubt get used to it. The drive home was unbelievable, so smooth, quiet and comfortable.

Just like normski2, I am indeed one happy bunny. Looking forward to many enjoyable hours of motoring.

[normski2]

Hey, nice one Geoff! Heartiest congrats.

th

That is an amazing mpg. I did get 37 odd for a while(around town mind you) but now its about 31 as I've been a little foot heavy driving with a bit of gusto and savouring it all.

Get some piccies up then!!

[noby76]

congrats on the new purchase :hocus-pokus: !! you had been looking for quite sometime now and the right one has come along! the noise level and smoothness will be quite different fom a diesel..I still cant hear my 10yr old IS3 engine idling when in traffic... which shows Lexus does Petrol engines very well...

enjoy!!

[Exdee]

Congrats!

No wonder you were inquisitive about the paddles on the is250.

Happy motoring! :)

[Carl911]

Oh, these threads just rub salt in the wounds.

[darkoracle]

That's very impressive mpg! Is that with the V6 auto?

I just did a round trip from Wales - Hastings - Northampton: a lot of motorway/cruise control and careful driving. Best I got was 37.7mpg.

Did you coast it down the hills?

[bluenose1940]

That's very impressive mpg! Is that with the V6 auto?

I just did a round trip from Wales - Hastings - Northampton: a lot of motorway/cruise control and careful driving. Best I got was 37.7mpg.

Did you coast it down the hills?

Thanks to all for the kind comments. I now know exactly how normski2 felt when he picked up his 250.

Yes darkoracle tis the V6 auto and no I didn't coast down the hills, in fact on a few occasions i put my foot down to get past a few cars on the run back. I was using the cruise control all of the time when on the A38 dual carriageway and, the highest that the trip computer showed on that part of the run was 53.5mpg. I really don't know gow accurate those computers are, Do any forum members know how reliable they are?

I expect to be spending a few hours messing around with the car today. It will make a change from laying turf (new lawn) and decorating. I have set myself a target of the end of the year for all of the work to be finished after our house move and then it will be all leisure and driving the 250! We have had 18 months of hard graft, extensions, patios, conservatories, decorating etc. etc. so am looking forward to lots and lots of trips in the car.

I'm sure that many of you will be thinking, if he didn't spend all that money on the house he could have had a new one!! Those are precisely my thoughts but, it pays to keep the peace methinks. I am happy enough, at the moment at least.............................but don't tell her indoors!!

[Exdee]

Your mpg figures are pretty high. Looks like your car has had an ecu reset and it will be a while before the mpg settles down to realistic figures. Don't think I've ever come across mpg figures you have quoted. But then again mpg is not my preferred display screen. I don't think I would have fun driving the car if I became too mpg concious. I know for a fact that I get 30ish in town and 37-38 on motorways at 80mph and that's good enough for me.

But I suppose If I was to move across from a diesel I would have the mpg figures dancing somewhere in the back of my mind.

[bluenose1940]

Your mpg figures are pretty high. Looks like your car has had an ecu reset and it will be a while before the mpg settles down to realistic figures. Don't think I've ever come across mpg figures you have quoted. But then again mpg is not my preferred display screen. I don't think I would have fun driving the car if I became too mpg concious. I know for a fact that I get 30ish in town and 37-38 on motorways at 80mph and that's good enough for me.

But I suppose If I was to move across from a diesel I would have the mpg figures dancing somewhere in the back of my mind.

I suppose that it's possible that the ECU was reset whilst they were prepping the car for me so you may well be correct that there will be some settling down to more realistic figures. i only watched the display from an interest point of view having changed from the 220d but, i certainly won't be doing that on a regular basis. I intend to just enjoy the car.

[rd27]

I always find my trip computer 3/4 mpg out, if you look on my Fuelly i've tracked over 6k in my IS250 auto and with each fuel up look in the notes section next to it and I quote indicated mpg.

http://www.fuelly.com/driver/rd27/is250

[michaelH]

I find the onboard computer on my current car overreads 'tank average' by about 2 mpg as did the one on my previous IS250 - assuming of course that when I check it against the recorded mileage for 'Trip A' the latter is spot on. But what if it isn't? On the 'fuelly' site one contributor suggests that if the speedo overreads by 5% (as many do) the the trip mileage may be out by a similar amount. In other words we may be driving further on one tank of fuel than the car says we are, so the mpg reading may not be as far out as it seems.

If trip A is underreading does that mean that the main odometer also underreading - has the car perhaps covered more miles than it suggests?

I am no engineer and don't have the time or resources to conduct detailed calibration exercises, although I could I suppose quite easily compare the mileage recorded against 'trip A' with that on the main odometer (and would then expect to find an exact match)

Otherwise I have no answers. Has anyone ?

[darkoracle]

The nearest anyone will get (assuming we don' trust the computer), is reverting to the pre-electronic methodology.

Fill the tank to maximum and record the base mileage (m1). Use the car until you feel the need to refuel, fill to the top and record the mileage (m2) and the amount of fuel litres added (fl).

Miles per litre: mpl = (m2-m1)/fl or

Miles per gallon: mpg = (m2-m1)/(fl/4.546095)

This of course is time consuming and gives only an overall efficiency based on your driving and the types of road travelled.

Not practical to do on each journey, but as a one off exercise – it’s interesting.

However it’s a Lexus and we didn’t buy it for its economy with fuel.

[noby76]

this will make things easier darkoracle!! i use it all the time and its calculations are accurate. go down to 'Real life miles per Gallon' and just fill in

price per litre of petrol!

how much fuel purchased,

and how many miles travelled on that fuel based on your trip computer's mile count and you will get your real world mpg figure...

http://www.fuel-economy.co.uk/calc.shtml

[michaelH]

yes, but this assumes the mileage recorded by the car is correct. Can we safely assume that it is? How accurate is the odometer and is it linked to the accuracy of the speedometer as the guy posting on the fuelly site suggests?

[noby76]

yes, but this assumes the mileage recorded by the car is correct. Can we safely assume that it is? How accurate is the odometer and is it linked to the accuracy of the speedometer as the guy posting on the fuelly site suggests?

you wont know how accurate your cars mileage count is until you have it professionally read using those high tec measuring equipment's but with trip computers in modern cars being digital i doubt they will be out of sync by a large margin and we know how Lexus pursuits to perfect every part/equipments on their cars so they wont be getting their odometers out of sync they might over read thier speedos for road safety as every car manufacture does but i doubt it will be the same for trip(mileage) computer count...cant really say the same for mpg figures the computer shows tho as all car manufactures makes their computers mpg figures look good hence i work mine out using the website based on how many miles i have traveled using trip computer count against cost of fuel.

[bluenose1940]

this will make things easier darkoracle!! i use it all the time and its calculations are accurate. go down to 'Real life miles per Gallon' and just fill in

price per litre of petrol!

how much fuel purchased,

and how many miles travelled on that fuel based on your trip computer's mile count and you will get your real world mpg figure...

http://www.fuel-econ...o.uk/calc.shtml

This is what I did with my 220d. I made myself a spreadsheet in Microsoft Excel and recorded all of the fuel purchased along with the reading from the odometer etc. etc.etc.. I found this to be a great help. I am pleased that I did this because as I mentioned in some of my earlier threads, the mpg I was recording when I first got the car was pretty abysmal, then I cleaned the EGR Valve and demonstrated what a worthwhile excercise that was.

[darkoracle]

Thanks for the link John – I’ve seen others like it. As a programmer in my former life I tend to write my own apps for things like this. I also have one for my Domestic Fuel Oil usage.

My favourite one is the car comfort equation.

Where Posterior size (ars) in centimetres and bucket seat depth ( b ) are calculated as a depression factor (g). This is considered alongside the suspension ratio (i) on the vehicle in question (is) and the speed of travel (at) against the condition of the road being travelled (f).

This equates to:

Comfort factor = f-at (ars/is)-2(b)/(i-g)

[fjcfarrar]

this will make things easier darkoracle!! i use it all the time and its calculations are accurate. go down to 'Real life miles per Gallon' and just fill in

price per litre of petrol!

how much fuel purchased,

and how many miles travelled on that fuel based on your trip computer's mile count and you will get your real world mpg figure...

http://www.fuel-econ...o.uk/calc.shtml

This is what I did with my 220d. I made myself a spreadsheet in Microsoft Excel and recorded all of the fuel purchased along with the reading from the odometer etc. etc.etc.. I found this to be a great help. I am pleased that I did this because as I mentioned in some of my earlier threads, the mpg I was recording when I first got the car was pretty abysmal, then I cleaned the EGR Valve and demonstrated what a worthwhile excercise that was.

It isn't easy to make accurate mpg measurements. The car calculates it from the outputs of a fuel-flow sensor (needed for the ECU) and the odometer. Neither are precise laboratory instruments but are usually consistent; so are fine for trends etc. Better results are available from continuously recording amounts of fuel bought over distance travelled - but these are subject to errors in forecourt pumps & odometers, which however tend to even out over time. You would have to be very, very lucky to achieve better than 3 or 4 percent absolute accuracy.

As you say though, it is better just to enjoy the car and only worry if mpg becomes noticeably poor.

[noby76]

Thanks for the link John – I’ve seen others like it. As a programmer in my former life I tend to write my own apps for things like this. I also have one for my Domestic Fuel Oil usage.

My favourite one is the car comfort equation.

Where Posterior size (ars) in centimetres and bucket seat depth ( b ) are calculated as a depression factor (g). This is considered alongside the suspension ratio (i) on the vehicle in question (is) and the speed of travel (at) against the condition of the road being travelled (f).

This equates to:

Comfort factor = f-at (ars/is)-2(b)/(i-g)

are you related to Albert Eistien?? :)

[bluenose1940]

Edit to my original post.

I think that I have got the colour wrong, I'm almost sure that it is Canterbury Blue.

[normski2]

Thanks for the link John – I’ve seen others like it. As a programmer in my former life I tend to write my own apps for things like this. I also have one for my Domestic Fuel Oil usage.

My favourite one is the car comfort equation.

Where Posterior size (ars) in centimetres and bucket seat depth ( b ) are calculated as a depression factor (g). This is considered alongside the suspension ratio (i) on the vehicle in question (is) and the speed of travel (at) against the condition of the road being travelled (f).

This equates to:

Comfort factor = f-at (ars/is)-2(b)/(i-g)

Love it, might need to change pants now! :)

Good to have a chuckle on a Monday morning.