58+ mpg

400 miles on 7.1 gallons is 56.3 mpg. Maybe you're looking at the mpg number on the display, which reads high by 5-6% (see the thread at the top of this section)

56.3 mpg is still very good. Where are you located and what kind of driving trips are involved?

 

Accelerate a tad more on the downhills if you have enough space to go faster.
Deaccelerate a tad more on the uphills if nobody is behind you.
Take your foot off the accelerator and allow the car to slow down to 15 mph before you have to do a full stop.
Avoid going over 55 mph.
Each trip should be atleast 30 minutes long.
Drive when the temperature is above 65 Fahrenheit degrees
Drive only on smooth asphalt roads.
Keep your AC/heater/defroster off
Keep your windows rolled up if you can.
Avoid traffic jams

 

Unclear from your post but sounds like he did 2 roughly 200 mile highway trips? As long as the speeds are not too high, long highway runs can yield surprising mpg because:
- the engine is warmed up only once; each warmup costs extra fuel
- as long as traffic is flowing, you can maintain momentum (though the faster you go the more you will have to change speed due to traffic, which will cost you)

AC load depends on how cold it is set. Very little load if it is set to a moderate temperature.

 

Not sure if all of the tips count.

My personal best so far of 58.2mpg calculated was on the foothills of Northern Virginia (Reston to Charlottesville to Reston to Dale City to Reston). About 1/2 of it 60+mph. All with the AC going!

Now traffic jams can be mixed. Doing a drive from Tysons Corner to Crystal City (about 15 miles) during rush I got about 78mpg on the MFD.

 

I agree with all of Walter Lee's tips. Low speed is definitely a plus: my PB for a trip is 135 miles at 76.8 mpg on the MFD (73.0 mpg after correcting for 5% error), running at 50mph, no AC, no CC. If I run the AC set a few degrees below ambient I have not seen much effect on mpg.

Traffic jams will kill mpg if the AC is on because the AC runs down the battery and the ICE starts to regen the battery. If AC is off and the jam is not too long there may not be much effect on mpg.

Highest segment I have seen is 52 miles at 85.5 mpg on the MFD, highway, 50mph, no jams. Most of the high mpg numbers come from segments started after the ICE is thoroughly warmed up, as it was in this case.

 

I dont use eco mode as much because I find I can get fairly good fuel efficiency with faster throttle response and thus makes for faster accelerations in normal mode as long as I limit the accelerations between .70 to 1.00 gph, 1088 to 1344 rpm. Immediately ramping up to atleast 15-20 mph from a dead stop makes my Prius and me a bit more tolerable in heavy traffic. Using electric motors beyond the initial acceleration from 0 mph to 10 mph is not necessary for high fuel efficiency but efficient use of the ICE throttle is. The ICE gets its best fuel efficiency when accelerating downhill.

 

i recently, (last week) drove from nj to nc and back and avg about 56 mpg. Going 65+ most of the time. I did the calcs myself instead of relying on the gauge, which at times on the way back read 60mpg. Most of the time its off by 2 mpg. If I wasn't already impressed with this car as it is, this would have floored me

 

Knowing what I do now, I am looking forward to a weekend R/T to the Delaware shore this coming weekend. Looks like the weather will allow the bikes to tag along on the Thule Raceway Platform rack. Already have a base for that trip under my belt using cruise control. Will post my findings early next week.

BTW, never too late in joining in on Fuelly to share more detailed info on your tank to tank mpg's.