RX450h Average fuel and economy

[TimS320]

I know there have been a few threads about fuel economy but hope I can start another as I seem to be getting quite low mpg.

I’ve had the RX for 8 months now and covered 2500 miles, with only two longish trips in the motorway, so I haven’t really been able to judge the motorway economy. However I’m driving up to the Lakes this weekend so it will be a good chance to see what I am getting. However round town and the back roads, all at fairly low speed, the Avg mpg display always seems to go down very quickly. If I’ve driven 10 miles and it’s showing 35mpg, a quick bit of dual carriageway drops it to 25mpg and that is without aggressive acceleration. Most of the time I’m only getting an average of 25.

Regular dual carriageway doesn’t seem to indicate more than 26mpg, which seems low.

I’m going to try a brim to brim this weekend and see what it gives but does anyone have any advice for getting the best reading and for improving fuel economy? 

[rayaans]

Sounds roughly normal on short trips and slow speeds. Remember that 26mpg in town is not bad at all for a 3.5l 2 tonne bohemoth.

Few things to check would be tyre pressures, the tyres themselves as they can make a huge difference and try maintaining momentum everywhere. Also, if you live in a hilly area, its going to be lower than someones mpg who lives in a flat area.

Hybrid driving styles may help. i.e. fast acceleration and then pulsing the throttle to maintain speed.

[steveledzep]

Had my RX fifteen months now and I've kept a brim to brim spreadsheet of fuel consumption.  I do a lot of 5 mile trips to work and back, a 20 mile trip to the supermarket fortnightly and occasional trips to Leamington Spa with a major Scotland trip last summer.

Winter mpg is around 28 to 30 and summer mpg is 33ish with the longer trips returning 36mpg or thereabouts.  I'm a steady driver so if you drive yours as if you've stolen it, expect less.

My dashboard mpg is just slightly optimistic to my actual,  yours sounds pessimistic to say the least.

[TimS320]

The tyres are all but worn out so I am looking at replacing all 4 with the cross climates. Hopefully this will provide a little increase over the old Bridgestone and Nexen that are on the car.

[Lex loafer]

My RX450h (2018) shows a regular 38mpg rolling average. My daily round trip to and from work is 80miles a day; mixture of motorway, traffic, towns. I drive at speed limits and in normal mode. 

Great car. 

[sorcerer]

Got our car on 2nd February and the best I've had so far is 30.7mpg - and that's driving like Miss flaming Daisy!

Even when the Battery is showing 7/8 bars (and on a few occasions 8/8) I only have to breathe on the accelerator and the ICE fires up screaming "Feed me".

I'm loving the comfort and luxury and the high seating position and I know it's a big engine and a heavy car but I was hoping for more from the hybrid. I sort of wish I'd gone for straight petrol and had it converted to LPG again instead.

 

[Lex loafer]

Interesting, I regularly drive along in a 40mph zone (at 40mph) purely in ev mode for a few miles  really useful on stop start motorway traffic. Started using the lane assist with active radar, scarey but clever.

My Battery icon only ever charges to 7/8, can’t seem to get that last bar .

 

[TimS320]

Not sure if we can do this on the older RX as the EV drops out at about 24mph when I accelerate. 

[DaveyBoy]

The 2016 luxury I test drove was difficult to keep in ev mode. I usually drive with a feather foot too! The dealer suggested that next year's model would probably not have an EV button.

[sorcerer]

3 hours ago, Lex loafer said:

Interesting, I regularly drive along in a 40mph zone (at 40mph) purely in ev mode for a few miles  really useful on stop start motorway traffic. Started using the lane assist with active radar, scarey but clever.

My battery icon only ever charges to 7/8, can’t seem to get that last bar .

 

We're comparing apples to oranges here Rob. You have a 4th Gen while the rest of us have 3rd Gen cars, so yours will always be better than anything we can manage.

[Glover]

This time of year I get anywhere between 36 and 41 with a combination of city, country A and B roads and dual carriageway/motorway. City only in the summer months will return low to mid 30s.  I'd say at a very rough estimate that mpg in the winter is 10 or so lower than summer.  In the winter I've gone as low as 24 and rarely get above 33.    

Last week and this is the first time for ages I had 8 bars on two occasions but it wasn't on a particularly long downhill stretch or braking a lot so heaven knows why that happened.  I used to drive like Miss Daisy but now I just keep up with the traffic and drive at the maximum speed limit where it's safe to do so with a bit of loud pedal to overtake slower traffic.  That does increase fuel consumption but it picks up again fairly quickly.   I also stick in Eco mode most of the time.

I'm in the East Mids and it's mainly rolling countryside although Nottingham itself has some excellent hills! so it's rare for me to get a perfectly flat stretch of road but I find that what I lose going up hills is usually recouped going down the other side.  Mine will sometimes go into EV mode above 40 but it is very sensitive; a slight dab on the pedal will often fire up the ICE  On the motorway in the summer consumption usually evens out at 36 with the cruise set at 77mph but on long uphill stretches it will fall to low to mid 20s; picking up again on the flat or downhill.

Recently I've been turning the air con off for short periods and it does seem to make a difference. With regards to tyres I have been running Cross Climates for about 18 months now; I can't fault them excellent handling, quiet and after a quite rapid loss of the first 1mm they have evened out and have lost 2mm in approx. 15,000miles.  I run 36psi all round.

After saying all of the above I must admit that now although I like to get good mpg I'm realistic that it's a big engine and the car is there to be enjoyed.  And very enjoyable it is too.  The best car I've driven by a country mile; a superb relaxing place to be and still puts a smile on my face when I get in it.

Hope this helps and above all enjoy your RX:-)

[TimS320]

Thanks, good to hear the Crossclimates are worth the investment. The MPG figures sound better and more what I was expecting. 

[Passerby]

I have been making regular trips of 120 miles along motorways and dual carriageways with cruise control set at 70mph for most of the way  33- 35mpg is always the outcome.

[rayaans]

Yep the 4RX uses petrol power to get up to speed but will go into EV even at 70mph. I turned the indicator off though because its annoying

The 3RX wouldnt do that - about 30 was its limit

[Glover]

First time I've disagreed with Rayaans on any subject but my 3RX will go into EV mode (or stay in EV mode) to well over 40.  Not sure exactly what speed it cuts out at but definitely not 70:-)

[steveledzep]

7 minutes ago, Glover said:

First time I've disagreed with Rayaans on any subject but my 3RX will go into EV mode (or stay in EV mode) to well over 40.  Not sure exactly what speed it cuts out at but definitely not 70:-)

Yes, mine will hold EV mode at 40mph too......only witnessed the motors helping the ICE above that speed.

[Mr Vlad]

My RX450h will cruise at 40mph on batteries alone for a few miles.

As for economy. I can't see the point in buying a RX450h and being concerned about its mpg. I got mine coz it looks good. Has the ML and seats my family excellently. Fuel economy doesn't come into it. Ok I only use it at weekends but so what.

[Glover]

31 minutes ago, Mr Vlad said:

My RX450h will cruise at 40mph on batteries alone for a few miles.

As for economy. I can't see the point in buying a RX450h and being concerned about its mpg. I got mine coz it looks good. Has the ML and seats my family excellently. Fuel economy doesn't come into it. Ok I only use it at weekends but so what.

Couldn't agree more. If I get good mpg that's a bonus but if I don't I'm not concerned.  The sheer pleasure of being in a Lexus is enough for me; just wish I'd been able to afford one years ago.  I use mine at weekends and holidays (although on work days every time I walk past it on the drive I think should I!

I have a 17 year old Yaris for my day to day journeys.  I do round trips of 150 miles plus some days with no problems; it passed it's MoT first time again today.  It's only failed once and that was a cracked rear spring (curse those speed bumps and potholes!).  Sorry to go off topic and mark but it's got the same parent as the Lexus! 

[chris_fletcher]

My gen4 RX rolling average since last July is 35.3mpg and the computer is strangely accurate and mirrors the calculated brim to brim consumption. Last tank as the weather warmed up was 36.3mpg and current tank after ~120 miles is on 37mpg. I expect the rolling average to reach around 38-39mpg by end of September and then start to drop as the weather cools.

Re EV mode. It will run purely Battery to 46mph and then the engine starts. At above 46mph when coasting downhill it will show the blue charge arrow only as if the engine is not working but the rev counter settles at around 1000rpm, So IMO the car will not run purely on Battery at motorway speeds

[TimS320]

Well managed 32.5 mpg up the M6 on Friday night 3 up and with a 12ft canoe on the roof, cruising at 70mph. Paid a lot more attention to the EV which came into its own on the slower sections. Getting stuck behind slow traffic on a gradient doesn’t help, but coasting down  those long sections tops the batteries up well.

[Mr Vlad]

Oh! Does the 4th generation RX have a rev counter? 

[chris_fletcher]

Rev counter comes on in Sport mode and can be configured on for Eco and Normal. My IS300H was the same

[rayaans]

4 hours ago, Mr Vlad said:

Oh! Does the 4th generation RX have a rev counter? 

Yes the 4th gen does, the 3rd gen doesnt

[Mr Vlad]

Thanks Rayaans. One wonders if by some electronic wizardry a rev counter can be put in the 3rd generation RX. 

[Glover]

Brimmed the tank today and got 36.4mpg (computer showed 36.3).  Just done a 50 mile round trip; first leg 39.5, second leg 38.3.  Bit of dual carriageway and remainder single carriageway A roads with approx. 5 miles suburban 30mph limit.  The computer on mine appears to be very accurate so those figures are probably within a couple of percentage points + or - of the real mpg.