ECO DRIVING MODE

[TEJLEXUS]

I am confused as to when to use the eco mode. I assumed that driving in normal mode automatically adjusts to give best fuel efficiency. However in the manual it says eco mode is when you are accelerating - so do you turn it on when you are on the highway and turn it off as soon as you slow down and take an exit??

[richmn]

shame that nobody answers a lot of these questions on here. From what I have researched and talking to Lexus certified mechanics, it appears that the eco mode has the best effect when used during stop and go traffic. The primary changes made by the system is to change the throttle profile by essentially slowing down acceleration, shifting sooner (lower rpms), and scaling back devices that cause high energy drain from the motor (IE: air conditioner compressor and internal fan speed for climate control).

Because of these functions, the effect of "eco mode" would be minimal when at highway speeds or maintaining a fairly constant speed. Normal mode is quite efficient and the unique ability of this motor to switch between the traditional Atkinson cycle and the Otto cycle will yield fairly good gas mileage even with the turbo. From my experience and what I have read online most owners that track their mpg manually notice less than a 1-2 mpg gain on long trips when this mode is enabled while highway driving.

[TrevC]

Hi Rich...welcome to the Forum

Unfortunately, this post got missed for responses but thanks for providing some information about the system operation. 

I recently road-tested an RX200t which by default would be in ECO and changed into SPORT mode when you put your foot down or if you manually switched it into SPORT. Otherwise, extra-urban driving was defaulted to the NORMAL setting, occasionally dropping into ECO when conditions allowed.

I found the engine performance and transmission shifting to be punchy and precise but fuel economy was a little disappointing, hindered by the fact that the car had AWD which it really didn't need and would definitely have improved the economy without it.

Cheers   Trevor