Fuel economy

Flames · June 26, 2016

Hi Everyone,

Had an 2003 RX 300 several years ago. We sold it due to the fuel consumption being a bit high. Now looking to get a 450h. Can anyone give me their thoughts and experience on the real fuel economy, as opposed to what the manufacturer claims ?

Thanks in advance,

Simon

rayaans · June 26, 2016

12 minutes ago, Flames said:

Hi Everyone,

Had an 2003 RX 300 several years ago. We sold it due to the fuel consumption being a bit high. Now looking to get a 450h. Can anyone give me their thoughts and experience on the real fuel economy, as opposed to what the manufacturer claims ?

Thanks in advance,

Simon

30mpg in town and about 35mpg on the motorway - all dependent on driving style and other factors of course.

Flames · June 26, 2016

So the reality is indeed a lot less than claimed by the manufacturers ?

rayaans · June 26, 2016

1 hour ago, Flames said:

So the reality is indeed a lot less than claimed by the manufacturers ?

Same with all cars, nothing new really.

sorcerer · June 26, 2016

52 minutes ago, rayaans said:

Same with all cars, nothing new really.

True. The manufacturers get their figures by removing almost everything from the car, such as passenger seats etc., and conduct their tests under laboratory conditions. I've always wondered how they are allowed to get away with this but obviously, they do.

We bought our very first Lexus, a 2005 RX300, about four or five weeks ago and I'm horrified by the fuel consumption (a best so far of 28mpg on the motorway and a worst of 17mpg around town). I knew it would be bad because it's such a big, heavy car but I didn't think it would be this bad.

I must admit though, that it's a long time since I had to rely on petrol alone. Our last car, a Nissan Maxima QX 3.0 V6 24V SE+ Auto, was converted to LPG within one month of us buying it back in 2008 and we went on to do more than 104,000 miles on LPG in it. It's for that reason that our RX300 is booked in for LPG conversion on 4th July and believe me, my wallet cannot wait!!

ColinBarber · June 26, 2016

3 hours ago, Flames said:

Had an 2003 RX 300 several years ago. We sold it due to the fuel consumption being a bit high. Now looking to get a 450h. Can anyone give me their thoughts and experience on the real fuel economy, as opposed to what the manufacturer claims ?

What did you get in your old RX300? 20 mpg around town isn't uncommon, you would get 30+ mpg in a RX450h which is also more refined and powerful.

My old 01 RX300 used to average around 25 mpg and I averaged 32 mpg in my RX400h - based on those figures I'd estimate an RX450h would achieve around 35 mpg under similar conditions. Motorway journeys are the hybrids weak point, I'd average 27 mpg in the RX300 and only 30 mpg in the 400h.

Flames · June 26, 2016

The old RX was in the low 20's round town and managed 32 on the motorway - there's lots of mis-information by the manufacturers about the fuel consumption, and that's not new. Our current BMW is meant to do 70 on a run but the reality is far different !

Cheers

rayaans · June 26, 2016

2 hours ago, Flames said:

The old RX was in the low 20's round town and managed 32 on the motorway - there's lots of mis-information by the manufacturers about the fuel consumption, and that's not new. Our current BMW is meant to do 70 on a run but the reality is far different !

Cheers

I used to get worse than that. I got 18mpg in town and barely 28 on the motorway.

I'm getting 30 mpg in town now

Flames · June 27, 2016

I see you have a 300h - is that a lot better on fuel in reality, and how is it as a whole. My wife has that as her second choice.

Regards,

Simon

rayaans · June 27, 2016

2 hours ago, Flames said:

I see you have a 300h - is that a lot better on fuel in reality, and how is it as a whole. My wife has that as her second choice.

Regards,

Simon

Its my wife's car and she only uses it in town for VERY short trips - gets about 30mpg.

I drove it myself for about 30 miles and got 45mpg.

Its a lovely car - very refined and a bargain looking at the spec list and discounts you can get on it compared to the competition!

Gliderpilot · June 27, 2016

Under normal driving, a mix of town and distance I'm averaging just over 30 mpg. Towing my large twin axle caravan I still get 25 mpg.

Assa1974 · June 27, 2016

Are these all actual figures or what the trip computer is saying? My computer often gives me mid-30s reported economy when in reality I've managed just over 30mpg on a run. Still not as bad a discrepency as my old Alpha 156 which used to report a range of over 1000 miles once I'd filled her up, then slowly adjusted down to the actual range which was just over 500 miles usually. Incidentally, why doesn't the Lexus computer give a range?

DanD · June 27, 2016

I have never managed the figures stated by Rayaan, maybe because I have a heavy foot and economy is not my priority, maybe also because mine is a pre-facelift model.

I consistently achieve around 29 MPG with 50% in town, 25% A-roads, 25% motorway. Also I live in south Hampshire, so not too many hills.

ColinBarber · June 28, 2016

17 hours ago, Assa1974 said:

Are these all actual figures or what the trip computer is saying? My computer often gives me mid-30s reported economy when in reality I've managed just over 30mpg on a run. Still not as bad a discrepency as my old Alpha 156 which used to report a range of over 1000 miles once I'd filled her up, then slowly adjusted down to the actual range which was just over 500 miles usually. Incidentally, why doesn't the Lexus computer give a range?

My figures were actual. Fuel computers on all my Lexus vehicles have always read 1 to 3 mpg beyond reality.

DanD · June 30, 2016

Out of curiosity, after filling up a couple of days ago, I put the car into ECO mode before a 30 mile cross country drive. Fairly flat, B-roads/country roads, light traffic, within the speed limit, but leisurely pace.

The car definitely felt a lot more sluggish (relaxing?), seemed to rely on the hybrid system a lot more, and sounded a lot quieter too. Amazingly, the readout showed 36.2MPG when I got to my destination.

Not sure I would do it again though, too much of a compromise. As I said, economy is not my priority and if it was I would have bought a different car. I'd find it a shame to spend my money on a RX, and then not enjoy its performance!

Zotto · June 30, 2016

Had you the air conditioner ON? ECO mode works on it too, and may be this has more effect on mpg, while other ECO difference is only in a different map on throttle pedal so you have to press more the feet to have same power; on my GS I use ECO just in long boring autoroute trips.

DanD · June 30, 2016

Yes I did have the aircon on. In fact, I never switch it off and leave it on AUTO to do its thing. I can see that ECO mode would work well on a quite motorway... I'll try in France next month!

Zotto · June 30, 2016

I prefer comfort to hypermiling too ;-)

ColinBarber · June 30, 2016

7 hours ago, Zotto said:

Had you the air conditioner ON? ECO mode works on it too, and may be this has more effect on mpg, while other ECO difference is only in a different map on throttle pedal so you have to press more the feet to have same power; on my GS I use ECO just in long boring autoroute trips.

It isn't just throttle map and aircon, ECO mode will switch to EV mode more often too.

Zotto · June 30, 2016

Sure? I see more petrol engine ON in SPORT rather less in ECO :)

ColinBarber · June 30, 2016

Definitely on the IS/GS300h. If I completely lift off it will go to EV at a higher speed, and it will also switch into EV much easier when I partially lift off, whereas in normal I'd have to completely lift off.

I agree that sport mode is the opposite, it keeps the petrol engine on a lot more and it holds a higher engine rpm under gentle acceleration.

DanD · July 5, 2016

Yes I did notice that. EV will stay on up to about 40mph, as long as you remain light footed. ECO certainly makes for a relaxing and quiet drive, but I would not use it in heavy traffic. One concern I had was that ECO mode might be potentially dangerous in that it could prevent a quick gateway or lane change, in particular with the pre-facelift version where you can't just switch ECO off at the press of a button. However, it seems that if you plant your foot firmly on the throttle, ECO mode is temporarily overridden and that you have access to all the power.

Haken8 · July 5, 2016

I have tried a number of modes since buying my 450h. In ECO mode ( sluggish/boring) I was getting 43MPG Motorway/34 MPG Urban. In normal mode 37MPG Motorway/33 MPG Urban.Not bad for the size/weight of car and definitely more enjoyable to drive in Normal Mode. As commented earlier in ECO mode you only have to lift of the accelerator a little for EV to kick in