Review: 2L VS. 2.5L Engine

GJ-Molestor

Banned
:
2011 BMW 528i, 2015 Mazda 6, 1995 Nissan Maxima Manual
Some background information: having driven the 2L Mazda 3 and 2.5L Mazda 6 (unfortunately both automatic) Im going to put together a little review on my impressions on these two motors.

Both of them feel similar. Responsive, rev happy, very linear power delivery. Both are smooth and make a great sound - all in all a great partner for the spirited driver while still delivering excellent, proven real world fuel economy.

Power Delivery

In the 2.5L, you have torque from 2500RPM all the way to the redline. A very healthy boost of torque comes on at 3000RPM with this engine and it feels very strong and responsive for a 4 cylinder. Power is steady and linear all the way up to the redline and throttle response is very good especially at high RPM.

The 2L engine is very linear, more so then the 2.5 but it needs to be revved harder to get going as Max torque is at 4000RPM rather then 3250. For a 2L, there is an impressive amount of torque below 4000RPM. This engine is easily more enjoyable to operate then just about all of its competition.

Transmission Tuning And Gearing

Both engines seem to use the same transmission and gearing, except the 2L has a slightly shorter final drive ratio to make up for the smaller displacement. During my experience with both cars, I found the 2.5L to be a far better match to the SKYACTIV transmission, especially when downshifting. In the 2L, flooring the gas pedal either gives you not enough or too much power every single time. Since the 2.5L has so much torque all over the rev range, all you have to do is lazily drop a gear or two and you are already in the powerband. The shift points are excellent and more useable out in the real world especially if you are a spirited driver. Due to all the torque at 3000rpm, I feel like the transmission shuffled through the gears a lot smoother and more effectively without needing to use much throttle at all. The car really takes off revving to 3000RPM and the gearing always keeps the engine on boil. The drivetrain tuning is simply better sorted with the larger motor.

Engine NVH

Both engines make a lovely sound and are very smooth (the 2.5L has balancing shafts but is just as smooth as the 2L) but the 2.5 is simply one of the best sounding 4 cylinders Ive ever had the pleasure of experiencing. It will happily rev to 6000RPM, but it is a very long stroke design meaning the engine sounds a little thrashy and unrefined near Redline - it prefers to stay in the midrange. You can hear and feel the engine breathe as you rev it out and it makes a lovely growl + a sweet brassy exhaust note. Large displacement motors are known to have lots of deep engine sound and there is no exception here; the exhaust note and engine sound from the front of the car is always heard and more distinctive/ growly with the 2.5L.

Fuel Economy

For a reserved, slow driver the 2L will get slightly better MPG, but I find that with any sort of spirited driving, the 2L engines fuel economy goes down the drain big-time. Since the 2.5L has so much more torque all over the rev range, you can rev the car a lot more lazily out in the real world. The more torque the engine makes at a lower RPM, the less throttle needs to be used.

Verdict

Both are truly great engines, but if you enjoy driving somewhat spirited the 2.5L will be the better choice without a doubt. Even for the very reserved driver, expect little to no penalty in efficiency by choosing the larger engine. Whatever slight disadvantage will be greatly offset by the effortless torque available on tap. In the 2L if you want to get going, you need to work for it.
 
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