Is250 Mpg Also Lpg

Sidster · January 3, 2015

Hi,

I'm thinking of getting a Lexus IS250 Auto. I've been looking online and the tech specification show the following MPG:

Urban 22.2 mpg

Extra Urban 40.4 mpg

Average 31.0 mpg

Is anyone getting anywhere near these figures. I know normally they are not very accurate and I do a lot of mileage so need to check!

Also I wanted to get the car LPG converted, but contacted a few companies and they said they can't as it s a direct injection system. Has anyone manage to get it done?

Thanks

normski2 · January 3, 2015

Don't know of anyone that has had a LPG conversion on the 250...don't think it can be done.

Local runs I get 29-31 in summer and 27 in winter.

Extended runs i get 36 with little effort. If you want to drive like grandad you can get 38-40 even.

It all depends where your mileage is going to be based.

I can do a run from Ringwood to Portsmouth that is reasonably flat (ish) and all on m-way and get 40mpg with cruise control and 60mph.

Stick in a few hills and it will drop back. Not bad for a 2.5 V6 really.

steveledzep · January 3, 2015

Hi Sid,

Only had my IS250 since 4th November. I can't comment on lpg, but my mpg experience is better than I expected.

I went to Mansfield to collect the car and the run home was about 200 miles (mostly motorway at 70mph, not using cruise) and I averaged 38mpg.

My daily commute is 5 miles to and 5 miles from work, with a 35 mile round trip to the supermarket every 8 to 10 days and I'm averaging 29mpg.

I expect these figures to improve in the warmer weather, and as Normski says "Not bad for a 2.5 V6 really."

Sidster · January 3, 2015

Hi Normski,

Thanks for the reply. That's not too bad for a 2.5 V6. Luckily my drive is mainly motorway and mostly flat :) . I was getting slightly better mileage with my Audi A6 2L diesel. I'd rather drive a petrol with slightly lower MPG than a diesel .

Thanks again - you have helped me make up my mind!

Sidster · January 3, 2015

Steve,

Thanks, seems pretty economical for a 2.6 V6. Looking forward to getting one now :)

stevet · January 3, 2015

Forget LPG for the 250. Nobody has done it for good reason.

steveledzep · January 3, 2015

Slightly lower mpg than a diesel, with petrol slightly lower in price = same cost !

A no brainer really when you consider the cosseted luxury and quietness of the IS compared to the smokey, rattly, noisy environment of the Audi.

You'll be treated with more courtesy on the road too, us Lexus drivers aren't considered pushy and aggresive like the Audi and BMW brigade !

Sidster · January 3, 2015

LOL - my Audi was not too bad, but ended up having loads of mechanical issues with gearbox and ecu.

Right now it's the hard bit - ~I've got to find one for sale with the spec I want.

Does the IS250 have a timing belt o is it a chain?

steveledzep · January 3, 2015

My understanding is that it's a chain.

Please post details of the vehicle you buy.....good luck in your search.

aviator888 · January 3, 2015

Don't know of anyone that has had a LPG conversion on the 250...don't think it can be done.

Is it because of the fuel injection setup or for some other reason?

normski2 · January 4, 2015

I did see an explanation on here in the past.....I think it was something to do with the injection system on this car. The LS400 is one you see conversions on.

Sidster.....its a timing chain not a belt. If you want one with all bells and whistles you should look for the SEL variant. If you can afford it look at the facelift version which is 09 and later. You can tell from the exterior as it has the distinctive 'L' shaped reversing lights in the rear cluster. You will also find a USB port in the armrest. Earlier models only had a phono jack socket in the armrest.

The navigation unit is functional whilst not earth shattering....if you get my drift. You'll get more from a Tom Tom etc. Having said that it works well, gives me updates on traffic situations (via radio info) and has taken me to a few areas in France with no problems at all. The facelift version has a HDD for the sat nav and not the DVD disc. You get updates via a USB stick that Lexus do. You can copy copious amounts of CDs onto the Hard Drive and still have 6 CDs in the unit.

The reversing camera I have found more useful than I expected....handy extra.

I find it to be a very very enjoyable motor. Engine and gearbox(auto) are sublime, it's comfortable, reasonably quiet, nippy when you want it to be and never tiring on an extended run. Wife loves driving it too!

My only gripes would be, the boot mouth is a little narrow, the rear seats don't fold down(would be useful) and the front and rear pillars are quite wide...but you get used to them and the allowances you need to give. The front pillar and mirror are a fair lump too.....so you'll need extra care at junctions for m/bikes and cyclists etc, again you learn to adjust. Rear leg room is a little tight...not as generous as the Audi. Not a problem for us as we are only 2 occupants, generally, in every day use.

Good luck with your search...take your time and find the car you want preferably with FLSH.

ChumpusRex · January 4, 2015

Don't know of anyone that has had a LPG conversion on the 250...don't think it can be done.

Is it because of the fuel injection setup or for some other reason?

It is because of the fuel injection and ECU setup, and the IS being a rare car, that no one has bothered making a kit for it. There are plenty of DI cars out there which have LPG conversion kits available.

Direct injected conversions are mechanically easier than normal conversions, because you don't need any mechanical engine mods - like gas injectors, vaporisers, etc. Direct injection systems work at super high pressure normally, and at these pressures, the LPG will be a liquid, so flow, pump and inject just like petrol. You just connect the LPG pipe to the engine's fuel pump via a selector valve (for petrol or LPG) and the LPG goes through the normal pump and injectors.

However, like all fuel injected LPG conversions, you need an ECU remap because of differences in combustion between LPG and petrol. The difference with DI, is that the ECU has a lot more control, and therefore you need a much more complicated remap. Designing an ECU map is a ton of skilled work, especially on modern DI ECUs which can have up to 250,000 different individual parameters to tweak.

I'm guessing that there has been no demand for the tuning companies to develop an LPG map for the IS250. In fact, I've not seen anyone offer a remap for the IS250 for anything - probably because of the complexity of the system, and the fact that Lexus have strong security systems on their ECUs to prevent unauthorised re-mapping.

normski2 · January 4, 2015

Thanks for the explanation....think you may have said all that before on a previous discussion... many thanks for taking the time to explain it all again to us.

Sidster · January 4, 2015

Hi,

Thanks for all your replies and advice. It's been very useful. I'm going to try to stretch my budget to get a 2009.

I've seen some lovely F-Sports in white - if only :(

PhilipK · January 4, 2015

I've had my IS250 since last July. In that time I've done 4,600 miles at an average 30.15mpg (calculated from actual petrol used, not from the car's computer). My best tank was 32.43mpg and my worst was 28.01mpg.

Most of the mileage has probably been motorway (weekly trip from Hampshire to West Midlands) with the rest around town. I've mostly only used Shell V-Power Nitro+ petrol in it, which has worked out at 20.01p per mile.

If you can find a MultiMedia version, the satnav is pretty good (it will dynamically reroute around traffic). You can use MP3 CDs in the Mark Levinson 6-CD changer, which allows somewhere between 80 and 120 songs per CD (depending on size/quality), so you can carry around 600 songs at a time. I also have a small DAB radio plugged into the AUX socket so that I can listen to Radio 6 Music.

The 2009MY post-facelift cars have a few nice, if not essential, features over the earlier cars (e.g. ability to autofold mirrors when locking the car).

dazed · January 5, 2015

Hi,

I'm thinking of getting a Lexus IS250 Auto. I've been looking online and the tech specification show the following MPG:

Urban 22.2 mpg

Extra Urban 40.4 mpg

Average 31.0 mpg

Is anyone getting anywhere near these figures. I know normally they are not very accurate and I do a lot of mileage so need to check!

Those figures sound about right. Compared with many cars the IS250 actually does live up to the published figures.

See http://www.honestjohn.co.uk/realmpg/lexus/is-2005/250

Fishboy · January 5, 2015

I've averaged 33mpg over 20,000 miles but I don't do any city driving and nick the wife's car for short journeys. I find the longer your journey the better the consumption, using cruise control also helps your average.

GaryD1975 · January 6, 2015

I've had my IS250 since last July. In that time I've done 4,600 miles at an average 30.15mpg (calculated from actual petrol used, not from the car's computer). My best tank was 32.43mpg and my worst was 28.01mpg.

Most of the mileage has probably been motorway (weekly trip from Hampshire to West Midlands) with the rest around town. I've mostly only used Shell V-Power Nitro+ petrol in it, which has worked out at 20.01p per mile.

If you can find a MultiMedia version, the satnav is pretty good (it will dynamically reroute around traffic). You can use MP3 CDs in the Mark Levinson 6-CD changer, which allows somewhere between 80 and 120 songs per CD (depending on size/quality), so you can carry around 600 songs at a time. I also have a small DAB radio plugged into the AUX socket so that I can listen to Radio 6 Music.

The 2009MY post-facelift cars have a few nice, if not essential, features over the earlier cars (e.g. ability to autofold mirrors when locking the car).

Can I ask what DAB radio you have and is it any good??

PhilipK · January 6, 2015

I bought a small portable Bush DAB radio from Argos (I got mine when they were on sale for £17.99 - they are now back up to £24.99). It has a rechargeable (via mini USB) Battery, so it just lives permanently in my arm rest with a 3.5mm jack-to-3.5mm jack lead connected into the AUX socket and a USB-to-mini USB connected to the power outlet there. It's always tuned to Radio 6 Music, and to listen to it I just have to hit the AUX button on the car's stereo.

It works well almost all the time. Occasionally the signal breaks up, but not very often (and when it does I just go back to CD or FM radio). Certainly better value for money (in my book) than the many hundreds of pounds that Lexus want for a DAB upgrade.

The full spec is available at http://www.argos.co.uk/static/Product/partNumber/9153219.htm