Rx450 Fuel Consumption

[auzoloto]

I'm considering purchasing a used RX450 but I'm concerned about the true fuel consumption. What are user's experiences? Thanks in anticipation.

[ROBJOBY]

I'm considering purchasing a used RX450 but I'm concerned about the true fuel consumption. What are user's experiences? Thanks in anticipation.

[ROBJOBY]

I have owned an RX450h Premier model for about seven weeks and I am very dissapointed with the fuel performance. See below my explanation as sent to the local Lexus dealer, who have tested my car and found no fault.

Published fuel consumption comparisons for RX450h and RX400h in miles per gallon.

RX450h - Urban = 42.8, Extra Urban = 47.1, Combined = 44.8

RX400h - Urban = 37.2, Extra Urban = 31.0, Combined = 34.9

Apparent improvement for 450h over 400h =

Urban = +5.6, Extra Urban = +16.1, Combined = +9.9

I previously owned an RX400h for over 4 years and I was consistently getting 32 to 33 mpg. This is 2 to 3 mpg less than published combined driving figures (between 6% to 8% less).

Also, I bought an RX400h for my wife and she is getting around 31 to 32 mpg regularly.

So far I am getting between 29 and 30 mpg from my RX450h. This is about 15 to 16 mpg less than quoted for combined driving (between 34% to 35% less)..

Whilst accepting that it is unrealistic to expect to achieve the quoted figures I was getting very close to the combined quoted figures for the RX400h regularly, yet I can’t get close to the published figures for the RX450h at all, in spite of having the same driving technique and travel patterns. This is why I am concerned.

Comments.

Having driven my previous car the RX400h for more than four years I have become quite accustomed to regularly getting between 31mpg (worse case) and 36 mpg (best case). The only times I have had less than this was for motorway trips at high speed, where I got between 28 and 30mpg.

My average was in the region of 32 to 33 mpg and the 36 mpg figure was only reached if I had included at least one trip to York (on A1079) between fuel fills. These figures have been frequently achieved throughout the winter months as well as the summer months,

I believe the reason for this is that the York trip involves lots of cruise control driving with the speed set between 45 and 55 mph, which means not much accelerating and decelerating and fairly constant speeds. Also we usually travelled at non peak times, with little traffic conditions.

As I’ve stated previously, I used the “Brake” mode whenever possible to help on decelerating and frequently cover many miles without needing to touch the foot brake, in the belief that this driving technique should help to recharge the propulsion Battery and enhance overall economy.

The net result is that I nearly always achieved an mpg figure which was within a few percentage points of the combined published figure for the RX400h. Namely I was getting 32 to 33 mpg against 34.9 published for the RX400h. This was achieved across nearly all my driving, the only exceptions were for occasional motorway driving, or extremely bad weather conditions.

Most of my driving is on country roads or around Hull, with a few trips per week of less than 10 miles duration, which obviously entails an undue proportion of cold engine running. My driving speeds on country roads is usually between 50 and 55mph.

Nothing has changed in the way I drive or where I drive, but I have a new car, which has published economy figures considerably better than the old car, so, naturally I was expecting some improvement, but I am getting significantly less mpg, although I did just manage 34 mpg on a round trip to York from a refill, but this is now being averaged down by more normal driving.

My conclusion is that there is some problem with the set up of the RX450h or the published figures are a sham. Were the published figures for the RX400h achieved using the same test parameters as those for the RX450h?

I am quite environmentally concerned, to the point of having a Ground Source Heating system at home and I am installing solar heating to supplement this, so the idea of changing to a more fuel efficient (although very expensive) vehicle suited my objectives, but it seems this has somewhat backfired and I now feel I am being fobbed off.

Over the last few years I have been more than happy with Lexus, barring a few silly niggles, but I now feel quite misled and disappointed, as a good part of my decision to buy the RX450h was based on the expectation of even better consumption figures than those achieved on my RX400h.

[tankplanker]

I get an average of about 35mpg, that's my normal driving style rather than shooting for economy and using super unleaded, which is worth an extra couple of MPG at least for me. A lot of that is sticking below 80 mph on the Motorways, go over that and the returned MPG is rather lower.

I can't get anywhere near the official figures, I've assumed that they are like the latest MPG figures from BMW for things like the 1 series, the result of the car being very good at the MPG test rather than having amazing MPG. I think this is made worse by the 450h being a hybrid, if gentle acceleration is used and/or a low enough speed I can see a big(ish) part of the test being done on electric only as if I remember correctly the test isn't exactly long.

It does strike me as weird that Car Manufacturers would think its a good long term plan to annoy and frustrate owners with unattainable MPG figures, sure it works in the short term but premium brands are based around retaining owners.

[Nick W858]

I'm considering purchasing a used RX450 but I'm concerned about the true fuel consumption. What are user's experiences? Thanks in anticipation.

Just had a SE-I 'loaner' from my dealer = great car, loved it - didn't feel quite as nice as my wifes Merc ML320cdi in some respects but overall I would take the Lex. Over a couple of hundred miles of fastish motorway miles (85-90) it averaged 29.2 which for such a big car is pretty good. My wifes ML has done 150000 miles and its average MPG overall is only 21mpg!

[gbch]

I had a RX400h for 3 years up until last September when I replaced it with a RX450h. Using the on board trip computer the RX400 returned 28.9 mpg over many thousands of miles and after 8500 miles the RX450 is returning 32.8. I have used standard unleaded for both vehicles, but I keep the Rx450 in eco mode.

A number of my friends and colleagues have also driven both vehicles and the difference in the mpg with different driving styles is very marked, both up and down. On a recent 200 mile mostly motorway trip a colleague got 38 mpg, but there were a lot of 50 mph sections!

[Rojah]

Hi there.

My current RX450 has averaged 34.4mpg since born 18,000 miles ago.

Much much better than my past RX400 which averaged 31.2 mpg over 80,000 miles in 3 years

Cheers

Bob

[Rillo]

Mine is coming up to 10,000 miles and is averaging between 28/29 to 36 mpg. One thing I did notice is that it is very sensitive to tyre pressures. My tyres were set at 36 all round. I checked the recommended and they are actually meant to be 42 rear and 38 front. having changed to these the mpg went up by 1-1.5!!

[R22flyer]

I have had my rx450h since 1st March and covered 2000 miles, I get 30-38mpg, best i had was 49mpg but this was very hard to get, I am pleased with it as all my previous 4x4 were X5 Petrol, Range Rover 2.7d and X6 3.0d were all getting just over 22mpg

[lfoggy]

Reading this thread it doesn't sound like the economy is that much better than the RX400h it replaces. I get 32 or 33mpg from my 400 so might expect a few mpg more at most. A little disappointing. The 450 is lovely though and I am still tempted....

[Rillo]

Let's be realistic here - just like many cars nowadays Lexus are tuned to do well in the mpg and CO2 tests for taxation reasons. I never expected my 450 to come anywhere close to the 44.8 stated.

My view - I drive a 2 tonne luxury petrol powered SUV which can shift if need be and still get over 30 mpg without trying. The glass is half full IMHO.