






2013 Ford Fusion




Source: Consumer Reports

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By EricMartello on 2/7/2013 9:51:50 AM , Rating: 1
Turbos allow smaller engines that are more efficient because they have less internal friction, and the reduced weight improves overall vehicle efficiency.

No, they do not have less internal friction. They do have lower static compression, but for a given power output both a turbo and NA engine will consume similar amounts of fuel which is what we're talking about. Efficiency is a measure of fuel consumed per unit of power produced.

Turbo engines are not substantially lighter than their NA counterparts because turbo engines (the reliable ones) have iron blocks. An NA engine can be perfectly reliable with a substantially lighter aluminum block.

Turbos also produce more lower end torque so the average engine rpm is lowered, also increasing efficiency.

That depends how the engine is tuned and what type of turbo you are using. A small turbo will produce more low-end torque at the expense of mid-range and top-end power - this translates to anemic performance on the highway when trying to pass or merge.

There is a myth being perpetuated on many car forums that engines that produce large amounts of low end torque are "better" because "most driving occurs at this RPM". This is not true. Your engine will regularly spin up past 3-4K RPM during normal driving unless you're driving like granny, and your low-end torque will nose-dive right around 4K RPM which means the acceleration from ~30 MPH to ~75 MPH (typical highway speeds) is going to be pitiful.

The IDEAL is an engine that has a broad, flat torque curve that does not fall off and allows the engine to rev higher and produce more usable power.

However, the trend is toward regenerative braking which reduces some losses associated with higher curb weight, and better materials, drivetrains, and lubricants have reduced the impact of friction.

Regenerative braking is not relevant in this discussion. That has to do with using braking forces to charge a battery of a hybrid or electric vehicle rather than dissipating all of that energy as heat. It adds cost and complexity to the vehicle, with an unclear advantage in terms of improving efficiency.


That's simply false.


Also false. You don't seem to get it. Torque is the ability of an engine to move a given weight a certain distance. Power determines how quickly the torque can be applied. It has nothing to do with a turbo - it's how the engine is configured.

There is no "efficiency" gain from a low-end torque bias in a vehicle that is not REGULARLY towing, plowing or otherwise moving large loads at slow speeds. This is marketing mythology that is highly prevalent on VW and Audi forums as justifications for how "great" the 2.Slow T engine is that seems to be in all of their cars.

However, the trend is toward regenerative braking

There is no trend toward regenerative braking and you clearly don't understand what it is or how it why bother bringing it up?

Go inflate your tires with helium so that your "effective weight" is reduced and your car drives like "it's floating on a cloud". $200 per tire filled.

