It's a 2.4, but hardly matters. It's actually a 170hp model, the 140hp was a software limitation that closes the throttle plate at upper RPM around 4500RPM and up.
The modern S60(2010-2015) is a far cry from the sizes of the old models, it was made as small as the P1 era S40. The S80 P3 model is the size of the old S60 P2.
Honestly I cannot say why the engine is so inefficient, maybe it was the weight + it being an automatic, who knows really.
My dad had several wagons/stations V70 850 740? The all did 1:10 and where manual. I think the large displacement, the 5 cylinders (is indeed heavyer) and low HP/L + naturally aspirated = inefficient.
My S60 is from the Ford-era and is basically a Ford Mondeo with volvo interior and exterior. In some sense it's too bad, it's not a 'real' volvo, I always loved the 5-cylinder sound, but I'd rather do 1:14-16
The modern S60(2010-2015) is a far cry from the sizes of the old models, it was made as small as the P1 era S40. The S80 P3 model is the size of the old S60 P2.
Honestly I cannot say why the engine is so inefficient, maybe it was the weight + it being an automatic, who knows really.