We compared Subaru Outback engines, and the efficiency crown goes to…
As one of the original “tall wagons”, the Subaru Outback has built a loyal following over more than two decades. It’s been offered almost exclusively with petrol engines all this time, with the sole exception being the short-lived 2.0 Boxer Diesel as used in the fifth-generation model. We’re about to see an all-new Outback soon, but in the meantime, let’s take a look at the current-generation’s engine options and find out which one is the most efficient.
Following the cancellation of the Boxer Diesel a few years ago, the Outback has reverted to its traditional engine selection. Buyers have a choice between a 2.5-litre horizontally-opposed (Boxer) 4-cylinder with 129 kW and 235 Nm, or a 3.6-litre Boxer 6-cylinder with 191 kW and 350 Nm.
It must be noted that local-market 4-cylinder Outbacks still use the old EJ-series boxer engine, which dates from the late-1980s, instead of the newer (and much more advanced) FB-series engine from other Subaru models. The Boxer-6 is much more modern, however, and both engines are paired with a "Lineartronic" Constantly Variable Transmission (CVT) to drive all four wheels through Subaru’s symmetrical AWD system.
Related: Find our review of the previous-generation Outback Diesel here.
Subaru Outback 2.5i-S ES Premium
This is the entry-level Outback, and has to make do with an old-tech engine. As a result, its outright efficiency isn’t the greatest, and it’s not hugely powerful for its size, either.
Average fuel consumption - combined cycle (manufacturer’s claim):
7.3 ℓ/100 km
Estimated fuel range (based on the quoted fuel tank capacity of 60 litres):
821 km
Subaru Outback 3.6 R-S ES Premium
Average fuel consumption - combined cycle (manufacturer’s claim):
9.9 ℓ/100 km
Estimated fuel range (based on the quoted fuel tank capacity of 60 litres):
606 km
Related: Read our review of the Subaru Outback 3.6 R here.
Verdict:
The Outback 2.5i is claimed to use an average of 7.3 ℓ/100 km, but prior experience has shown that this number is wildly optimistic. In reality, owners can expect closer to the 10 ℓ/100 km mark – or even more. The fact is that the Subaru EJ-series engine has a well-deserved reputation for being a profligate drinker, and the presence of a power-sapping CVT and the Outback’s raised ride height doesn’t do anything to make its drinking habits more palatable.
However, it’s still bound be a fair bit less thirsty than the 3.6 R. The range-topping variant doesn’t only have a more-potent, larger-displacement engine, but it’s heavier overall as well. It does have a fair bit more torque, though, which should make for a proportionally smaller consumption penalty when fully laden – but the big six will still drink a fair bit more than its 4-cylinder sibling.
Related: Find out more about the current-generation Subaru Outback range, as it looked at launch.
Overall, the Outback 2.5i-S wins the efficiency crown, but that’s not really through any virtue of its own. Instead, it walks away with this title because, while the 2.5i is pretty thirsty in its own right, the much more-potent 3.6 R is much worse in this regard. If only there was enough market demand to justify the return of the sweet, frugal Boxer Diesel...
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