Subaru Forester e-Boxer fuel consumption – long term data

It is very interesting topic to discuss about the Subaru’s first hybrid Forester fuel consumption or MPG if you will. Looking at the official WLTP numbers, it seems that Subaru managed to improve fuel efficiency little. According to Subaru, new e-Boxer Forester can save in fuel consumption up to 11% compared to non-hybrid variant.

Subaru Forester e-BoxerWLTP (lit./100km)
Low8,8
Medium7,5
High6,7
Extra-high9,5
Combined8,1

Combined WLTP fuel consumption is 8,1 litres per 100 km. Bear in mind that this is done in certain temperature and official WLTP cycle just little over 20 kilometers. So driving in different temperatures, it is expected to have different results. Of course, colder it is, worse the fuel economy will be. Tank capacity is 48 liters. Depending of your driving style and conditions, cruising range is somewhat 500 km.

Winter vs summer fuel consumption

I am using 95E10 fuel at winter and summer. That fuel type contains maximum 10% of ethanol. Some believes that higher octane gasoline is better. Either it would save some fuel or give extra power for your car. I do not believe that. I’ll just use what is recommended by Subaru.

Tires have also impact to the consumption. During winter I am using Continental Viking Contact 7 (non studded) tires, 17″ wheel. Summer tires are those which came with car, i.e. Bridgestone 18″.

Outside temperature has also impact to the fuel consumption. Last winter was almost like a “long autumn”, it was not a proper winter at all. Temperatures were above zero Celsius. So unfortunately I do not have data available how e.g. -15 Celsius would affect. Hopefully we can see that next winter. Traditional colder weather affects to the consumption like camel drinks water in Sahara desert. Only comparable data I have available for now is that I did “hypermiling” tests in zero degrees vs 20 degrees. Results was 5.7 litres vs 4.9 litres per 100 kilometres.

Speed kills fuel economy

Above I state that outside temperature has a impact to the fuel economy. That is true but then also speed affects to the fuel economy greatly. Particularly true it is with taller cars such as Forester. 4th generation Forester (SJ) has drag coefficient of .37 cd, 5th generation Forester (SK) should be close to that too as the exterior shape is pretty much similar than it used to be. In comparison, drag coefficient champion, Toyota Prius has .24 cd.

Below table is not measured by any means, rather these are results of my experiences from summer period. Please note terrain forms affects, wind direction affects. So these observations are not that accurate but gives an idea what the consumption is in different speeds.

Speed (km/h)fuel consumption (litres / 100 km)
605
806.5
1007.2
1208.0
city10

Distance

3rd main factor which affects to the fuel consumption is distance you drive. In short distance driving, engine never gets to the optimal operating temperature and hence relatively average consumption is higher.

Short distance driving might be also harmful your car. E.g. GPF filter needs regenerating procedure more often. This filter is installed only in the EU spec e-Boxer models. US models are free of this device. Lucky you!

Subaru Forester e-Boxer monthly fuel consumption statistics

Table below is presenting real world consumption figures of my driving. See journal below to learn more details from each month.

Monthdistance driven (km)liters / 100 kmUS MPGUK MPGAvg. outside temp.Tyres
January14788.228.734.5+3C / 37.5Fwinter
February18438.328.334+1.4C / 34.5Fwinter
March12408.228.734.6+2.4C / 35.6Fwinter / summer
April5908.228.734.5+5.1C / 41Fsummer
May8487.63137+9.6C / 49.3Fsummer
June7757.929.835.8+17.9C / 64.22Fsummer
July23267.431.838.216.7C / 60.8 Fsummer
August5848.42833.617.1C / 62.8Fsummer
September5968.527.432.813.8C / 56.8Fsummer
October8508.527.432.89.3C / 48.7Fsummer

Journal of the fuel consumption (2020)

Before the Covid-19 pandemic I used to drive to my office daily. 8km distance one way. So very short trips and cold starts for the engine. That did not do good for the fuel consumption. Now during pandemic I don’t need to drive to office any more but I still have some short distance driving, e.g. to grocery store. But then also some long distance driving during my free time.

Below I have gathered monthly insight of the fuel consumption for those who are interested what type of conditions each month had and what type of driving it included.

January

This was only half month what comes to the driving. I received car mid January, brought it to home from the dealership. First 500 km was long distance driving. Speed limits from 60 to 100km/h. During that trip fuel consumption was 7.1 liters per 100 km. Outside temperature was few degrees over 0 Celsius by then. Next I had some short distance driving. To work, back to home, to the grocery shop, etc.. That increased consumption to 8.4 liters per 100 km. Few longer work trips via a highway. Some city driving with lot’s of traffic lights. Total 1478 km distance driven. Average temperature for January +3 Celsius (Helsinki) and average consumption was 8.2 liters per 100km.

February

February started with a bit colder temperatures. That was shown as slightly increased fuel consumption. Nothing major. On this month I decided to do a “hypermiling test“. My goal was to beat official WLTP figures. Test went quite fine indeed, given that it was conducted during winter time. Result for that 60km test was 5.7 liters per 100km.

During this month GPF orange warning light lit also. Luckily I managed to get rid of that driving in certain conditions. Please check separate post of it.

Otherwise February included some driving through storm, some longer business trips and then short distance driving between home and office. Roughly 400km more than in previous month. From weather wise this month was bit colder than January, average of 1.4C. We saw even a glance of snow.

March

March started with some business related trips, which generated kilometers to the odometer. However from mid month we got advise from the employer to stay home and quickly after also from the government similar advises due to the domestic (and global) virus issue. So in March it seems that there is less distance driven and in general shorter distance driving, which increases fuel consumption.

Summer tires was changed on 24th of March. So that is also interesting to see how those will affect to the consumption. Winter tires are inch smaller than the original 18″ summer wheels.

I would assume that upcoming summer months will have still lower consumption figures. Bigger tires will increase consumption but warmer weather does have a greater impact. Thus lower fuel consumption is expected.

Final figures for March are 8.2 liters average consumption and 1239.7 km driven.

April

April seems to be bit odd month. At least first half of it. Currently average consumption is 8.4 liters per 100km. Which is higher than expected. Days have been warmer and that should have positive impact. Although work related driving is nearly zero due to the global pandemic. There has been less free time related driving too during this month.

April update: Less than 600 kilometres driven at April. Significant drop is because I have been working fully from home. So basically that is only some hobbies related driving or just going to grocery store.

Hopefully weather gets warmer during May and then also fuel consumption should drop too. I expect well below 8 litres per 100 km numbers. Let’s see!

May

I was right that outside temperature has a major impact to the fuel consumption. Beginning of this month was bit colder but on the otherhand latter part of the month was warmer. Specially these last days before heading towards June.

I also made a “hypermiling” test, similar test than I did during winter. Just to see what kind of impact weather does have. I recommend you to check at least summer test. Interesting results I would say!

So the average consumption for May was 7,6 litres per 100 km and total distance driven 848 km.

June

This month result was really unexpected for me. I though final results would be closer to seven litres per 100 km but it was actually 7,9 litres per 100 km. Weather has been extremely nice so outside temperature is favoring fuel efficient driving. It seems that for certain point temperature has a positive effect but the most biggest factors are speed and then distance.

This month distance driven is 775 km. Mostly short trips to get some supplies for the newborn baby and some food from grocery stores. That might actually explain “bad” fuel economy. There was some longer trips too but certainly that many as in previous months.

July

Record so far in monthly driving. In both distance driven and in fuel consumption. This month figures underpins that it is possible to get decent fuel economy when driving more long distance driving.

Half of the July’s driving was pleasure driving to relatives and other half very similar driving that I have been doing through out the year already.

August

If July was new record of monthly distance driven, so it was also in August. This time opposite. This was the shortest distance driven in one month. Only 548 kilometres. And mostly short trips. I also expected that GPF light would lit on once again but luckily that did not happen. Short trips also is immediately shown on the fuel consumption figures. For this month it was 8,4 litres per 100 km.

September

Global pandemic situation keeps mileage figures still low. In terms of driving, September was pretty much alike with August. However during this month average consumption was the highest with 8,5 liters per 100 kilometer. This was somewhat surprising as outside temperatures were relatively high through month. E.g. at April it was much colder but still little lower consumption.

October

At October I returned to my “new normal” driving distances by driving 850 km during this month. Mostly normal trips here and there (grocery stores) but we had also one hotel vacation in city of Hämeenlinna. Weather did not favor our visit but Subaru did not complain any of the gross winds. I guess this longer trip also was good for the GPF filter, although I have not yet learned to “feel” it when regeneration happens in normal operation.

From the fuel economy point of view, last two months has been most fuel sipping months by 8,5 liter average consumption. Reason for that is that short trips really increases the consumption. One longer trip does not “save” the fuel economy.

20 comments

  1. Same consumption, from 7,1 – 10,5 l / 100 km depending where, how long, etc. Average is about 8,1 – 9,2 l. Also, as warning light of low fuel level start somewhere when 7 l left, you could end up even not reaching 500 km distance. Are you using E95 or E98 fuel?

    Have you figured out in what occasion hybrid electric motor starts? For me it seems very chaotic, some days it only kicks in when accelerating. The other day in starts even in 80 km/h when lifting gas pedal and goes on full EV until you step on again. Then you can go slow in muddy road only on EV. Just have’t figured out what conducive habits are.

    Liked by 1 person

    1. I am using 95 E10 fuel (max 10% ethanol) as it is little cheaper than 98. I have not used MFD screen at all to monitor when electric motor does something. For me it has been surprise that it goes to full EV mode quite often. Didn’t quite expect that. Thought it would be working on the background mainly. I guess chiller temperature might have something to do with the behavior you described? I bet during summer it is more refined.

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  2. I am purchasing a hybrid Forester in about 4 weeks – I would have thought short trips or driving in the city with traffic lights and roundabouts etc would give the Forester a chance to utilize the small battery more often? I have another question for the fuel consumption on longer trips – what speeds are people going and are you on a freeway where the speed is constant for a long period of time? I am sure 90kmph will deliver improved fuel consumption over 110kmph. I am in agreement that in summer the air con will not be working as hard and possible give the electric motor more chances to engage.

    Liked by 1 person

    1. On freeway I get 7.4 at 100km/h speed. City driving is the worst what comes to consumption. Roughly 9 liters per 100km. Hybrid system utilizes electric motor in most situations. It only does it in together with gasoline engine. So it is not so easy detect. Electric only situations occurs often when approaching e.g. red lights.

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  3. I’ve driven some 5000 km now, and get 9 litres to 100km. Good enough, the car is thirsty because of the symmetrical all-wheel drive but that translates into super safety in bends, through water, and of course when engaging in fun off-road adventures.

    Like

  4. Hi
    As I also searching for a very solid & safety car, I found this very interesting page. Congratulation for your hobby and for your time you put here!

    Because I want to buy the car for mainly highway driving, can you please share the consumption experience when driving only on highway at around 130 – 140 kmph? I will use the car for long distances (1000-1500 km one drive) with 80-90% highway … and I expect not an acceptable consumption comparing with a normal 2.0l diesel.

    thank you upfront for your feedback, Catalin

    Like

    1. We have winter speed limits at the moment. So maximum speed is 100km/h. But even during summer limits I would not drive that fast. Consumption could be easier near 10 litres per 100km. Diesel car would be far more economical option for your case.

      Thanks for the feedback!

      Like

  5. Hi, I have a question about eyesight system.
    Have you had the opportunity to try it?
    How do you rate him?

    And another question about e-boxer. Are there any jerks when switching on or off the electric motor?

    Like

  6. Hello
    Breakdown of consumption by deposit:
    31.4L of 48L (before reservation 16.56L remained)
    Kilometers traveled 583.5km consumption of 6.7L
    Motorway, highway and city routes speeds of 50, 80 to 110km / h.
    Outdoor temperature between 17º to 21º
    Petrol 95
    Summer tire and 17″.

    Spain-Barcelona.
    A greeting.
    Oscar.

    Liked by 1 person

  7. good morning,
    my highest concern is fuel consumption on that car, right now iam very happy with my diesel but need to purchase bigger suv due to familiy.
    i did a test drive with roughly 20km in the city with gentle gaspedal 50-60kmh.
    results 7.3l
    was quite excited , because of reading consumption up to 9-10l.

    Like

      1. yes,
        we had 15-20C degress i guess.
        do you have figures for driving highway with ~120kmh, full cargo, roof-box and biycles on tow hitch?

        Like

      2. Sorry, no experiences of that.

        I think I have posted information of the consumption ~100km/h. That was without cargo and roofbox. If I don’t recall completely wrong now, it was somewhere above 7 liters per 100km. I am planning to create newer consumption test which includes higher speeds in warmer temperature. That takes still few weeks to get it ready. Stay tuned!

        Like

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