Gas Mileage - New RX 350h

[Tblaney]

We just picked up a 24 RX 350h.  What gas mileage should we expect with 250 miles on the car?  Right now we are averaging 27.5 on the dash.  I was expecting more in the mid to upper 30's.  Does it get better as it engine break-in is complete?

[Carbuff2]

The displayed MPG is dependent on usage.  Will probably get better. Our 500h requires 40 - 80 miles before it reaches the typical, normal MPG. (We reset our display MPG each fill-up...old habits die hard.) 😗

 

Did your dealer sit you down with the engine on/idling while showing you the dash setup and all the 'bells and whistles'? That typically reduces the indicated total.

 

Give the car a couple tanks of fuel before you start worrying.

[Tblaney]

We have had a few tanks of gas now, and I haven't seen it get over 28 MPG.  I was expecting it to be in the mid to upper 30's. 

[Les Lex 2018]

You may be running short distances where the engine is cold and being choked.

Do this:  Reset the MPG. Start up cold and check after 2 miles.  It should be around 25 to 27.  Cold engines gulp a lot of gas.

When the engine is hot, reset it again and check it after about 5 miles.  It should be in the 36 to 40 range.  

Colder weather and turning on your heater keeps the engine running longer too.

Example: The ES300h gets like 34 mpg in the first 2 miles.  But running from a warm start to finish in the city, it gets over 50 MPG, believe it or not.

So short distances and high speed highways take a toll on MPG.  The RX is not very aerodynamic.  The ES sedans are.

[Tblaney]

Our garage is heated.  So the car is at 65F.  the road to the highway is about 4 miles of 35 - 55 mph with 2 stop signs.  it's than 15 miles to town at 70 MPH.  One of these trips, the gas milage will be 27 MPG never higher.  

I agree it should be in the thirties, which is what the window sticker says.  I am wondering why have have never got over 28mpg.  It now has about 1,200 miles on it.  So it's being used.  

[Les Lex 2018]

First some comparison info that will not help you a whole lot.  My 2020 Rx 350 V-6 got 18 mpg in town in real cold weather. About 20-22 in warm weather.  Pure highway got 27 short trip, to 30 mpg long trip.  But not running 70 mph.

In multiple hybrids and RX's, I've always found TMC vehicles to very accurate on mpg display. So that's a good tool for doing your comparisons at different outside temps and speeds.

Take your data to Lexus and have it analyzed by a good hybrid tech at Lexus.

One more data point to look at:  The ES hybrid has a CVT and optimized engine efficiency system that is getting an engine cycle time of 50%.  That's why it gets 50 MPG hot start to hot finish.  So get your passenger to use their watch timer to compute how long your engine is running vs. the length of the trip.  The longer your engine is kept running to maintain your speed, the closer your RX will register to the mpg of a regular RX 350 without a turbo which I don't believe you have.  I'm guessing your engine cycle time will may be closer to 80%.

You're almost there with your data.  My only guess would be that you're locked in performance mode and don't know it. Getting a engine cycle % in both ECO and Performance mode would tell the story there.

 

[Tblaney]

Thanks for the reply on this.  It definitely helps getting other peoples perspective on there experiences.   

I am guessing we are at 80% as well, but will start to time it.  So I am timing correctly the engine is on when the Green EV light is off, is that correct?

No, we don't have the turbo.   We stayed away from the rx550 because of the gas milage.  That had a window sticker with MPG between 26 and 28.  

 

More info to come.  Thanks again for the help.

 

[Les Lex 2018]

Your 24 should have a switch to change modes.  That should be set to ECO, unless they changed that.  To time your engine, bring up the hybrid engine display on the screen.  the display will show when the engine is running and when the hybrid battery is charging. Pay attention to the engine running arrows.  It's red when pointing to the wheels or bat. Stop watch it so you get only the run time.  Then look at the total run time in minutes which can be selected and displayed in front of the driver.