MPG for Lexus IS300h F Sport Owners

[Robertdt]

The current tank of fuel i have nearly used up has given me an average of 47.5 in my 2019 F-sport, always on sport mode (throttle response on eco borderline dangerous IMO, plus sport mode uses no more fuel IMO). Car pretty much only does 16 miles each way commute to work at 55-65 mph. In winter in averages 42-44.

Rob.

[agent_dess]

1 hour ago, wharfhouse said:

Based on the official emissions data then the difference between 17" and 18" should be about 5% - so that should make a difference of about 2 to 3 mpg. 

Yeah I'm not convinced tyre size would make dent in the mpg.

[hieronymous]

12 hours ago, agent_dess said:

Yeah I'm not convinced tyre size would make dent in the mpg.

My 2021 IS300h F-Sport runs 235/40x19 (F), 265/35x19 (R), but in our current winter temps of about 15C still is returning 58mpg on the current tank, and on a recent 75mile run returned 60mpg. Hybrid fuel economy is always, and only, down to speed, or more accurately, average speed - our limit is 100K, and I cruise at 90GPS (59mph indicated). Having come to the F_Sport from 2 Prius’s, I also use cruise control as much as possible, and generally hyper-mile letting the hybrid make the decisions.

Despite the big hike in the fuel price (currently here about 1.60 pounds/litre), the 300h remains competitive with my Kona EV at public charger rates, both about 8p/km.

[Tel]

A Hybrid tends to give you more power than a non hybrid & therefore better potential mpg.

Driving 4 Peeps up the Alps @ 80 mph achieved 25 mpg whilst descending into Italy the mpg was 58.5.

6 Year average in D-Sport was c.42 mpg.

Tel

[Liamob1]

2014 F Sport That I drive on half country roads with a fair bit of over taking and half motorway. Averaging 45 MPG which I think is great. 

[Colinb623]

Is everyone's figures on this based on the dash readout or an actual mpg calculation?

[hieronymous]

3 hours ago, Colinb623 said:

Is everyone's figures on this based on the dash readout or an actual mpg calculation?

I’ve tested this by the usual method - from a service station adjacent  to a motorway, by filling the tank from a reliably hands-free, auto-shutoff nozzle, running a motorway loop (50ml) back to the same nozzle, and refill.

The IS300h dash readouts (reset and refill) both matched the pump receipt, within the limitation of data to one decimal place - it’s close enough given the general assumption that station pumps should be accurate, maybe..

However, it is noticeable that day-to-day short running, especially in winter, can result in quite a gap between the reset and refill values. Cold starts, and manoeuvring in and out of garages and car parks, use a significant amount of fuel, which is usually ignored. So, while a reset result can be a useful snapshot of a particular route or set of conditions, especially over longer distances, the refill value is a much more accurate indicator of typical consumption..

So the 60mpg (posted above) is one reset value from the current tank, but I have also had 51mpg. However, the refill value is steady at 56mpg.

[route66]

15 hours ago, Colinb623 said:

Is everyone's figures on this based on the dash readout or an actual mpg calculation?

If you read my submission, you will see I quote both.

I generally record the difference and my experience over 54 fillups shows that the value from the dash readout overreads on average by 7%.

[agent_dess]

I will be heading to London in in just over a week so will be interesting to see what i get now that i have cruise control (i didnt have it when i bought the car.. long story the stalk was broken).

Back in 2014 when we went to London in the IS250 we got 42-46mpg.

Im hoping to break past the 45mpg barrier this time and get closer to 50mpg... that said it will be a full car with suitcase and pram in the boot.

That's 442 miles each way.

Would you suggest keeping car in Eco or Normal?
I plan to keep cruise control at 65-67mph

[wharfhouse]

45 minutes ago, agent_dess said:

I will be heading to London in in just over a week so will be interesting to see what i get now that i have cruise control (i didnt have it when i bought the car.. long story the stalk was broken).

Back in 2014 when we went to London in the IS250 we got 42-46mpg.

Im hoping to break past the 45mpg barrier this time and get closer to 50mpg... that said it will be a full car with suitcase and pram in the boot.

That's 442 miles each way.

Would you suggest keeping car in Eco or Normal?
I plan to keep cruise control at 65-67mph

I use Eco and cruise control on the motorway and IIRC that's what Lexus recommend for best fuel consumption. In these high fuel prices I set the cruise at an indicated 75mph (which is actually about 70mph as the speedo overeads  by nearly 10%). Also leave plenty of space to avoid braking unnecessarily and accelerate smoothly and reasonably briskly up to speed (so not too slowly as that is actually worse for fuel consumption). 

I did a 300 mile journey from Berkshire to Cumbria last week and my overall fuel consumption was 55mpg (on the car computer) - this was with my wife, a dog, and boot full of luggage. Traffic was reasonably light so I was able to maintain a constant speed for long periods. I was using Sainsbury's 97 super unleaded fuel (I have 17" wheels however). Let us know what you achieve. 

[royoftherovers]

2 hours ago, route66 said:

If you read my submission, you will see I quote both.

I generally record the difference and my experience over 54 fillups shows that the value from the dash readout overreads on average by 7%.

The Dash read out from my 19 year old Merc has over read by 8% for the last 19 years. 

[agent_dess]

Just got back home after driving 1356 miles and gotta say was impressed by the car.  Got 550 miles on a full tank and seen between 47-54mpg.  Overall I'm happy with the outcome ☺️

[wharfhouse]

4 hours ago, agent_dess said:

Just got back home after driving 1356 miles and gotta say was impressed by the car.  Got 550 miles on a full tank and seen between 47-54mpg.  Overall I'm happy with the outcome ☺️

Good to hear you started seeing mpg in line with others on the forum here.