Most cars have their engines under the bonnet, but that's not always the case. Auto engineers sometimes use mid-engine or rear-engine mount, and this has something to do with the car’s performance, stability, and handling.
People looking to buy cars may not be particular about where the engine sits, but it's a big deal. The car layout, particularly engine placement, affects the configuration of the rest of the vehicle.
Front-Engine Cars Vs Mid-Engine Cars Vs Rear-Engine Cars
Here are three different engine placements and how they differ from one another.
1. Front-Engine Mount
In front-mounted engines, the power plant is placed in front of the axle. This configuration can come as front-front or front-mid depending on the engine position relative to the front axle.
Pros of Front-Engine Cars
The front-engine mount is the most common type of engine placement in vehicles. Why is this so? Well, it is only logical to have the engine positioned in such a way that it offers the most traction to the front wheels and makes the vehicle more stable.
Additionally, front-engine cars have roomier cabins. In head-on collisions, this placement also offers protection to the passengers.
Cons of the Front-Engine Car Layouts
Like everything else, front-engine cars have their flaws. Front-engine mount front-wheel-drive vehicles suffer from understeer when accelerating.
On the other hand, front-engine rear-wheel-drive cars experience less of this hitch and are considered ideal, but they still can be challenging to control in slippery conditions.
Performance-wise, this engine placement is disadvantageous because a lot of power is wasted trying to send the output through the entire car to turn the rear wheels.
Front-engine cars also lose out on their braking capacity due to the weight shifted forward hence creating momentum in the unwanted direction.
Vehicle manufacturers try to counter this problem with features like power steering, anti-lock braking system (ABS), vehicle stability control, and traction control.
This placement is unsuitable for race driving cars because of the drawbacks mentioned.
2. Mid-Engine Mount
In this type of placement, the engine is mounted between the axles of the automobile. It can be front-mid or rear-mid.
Pros of Mid-Engine Cars
A mid-engine mount offers perfect balance for the car as all four wheels equally share the engine’s weight. Equal traction in all four-wheels improves stability, especially when negotiating bends.
This position is typically found in sports cars, e.g., the iconic Ford Mustang and the Audi R8 supercar. As the engine is ahead of the rear axle but behind the passenger, vehicles with this placement rarely have more than a two-seat occupancy.
Cons of Mid-Engine Mount
Cars with this configuration can be hard to handle once they spin out of control. With its weight evenly spread, neither the front nor rear wheels have the ground grip to stop a spin.
Servicing and repairing can also be tricky. The central position of the engine makes it hard to access compared to front-engine placement.
3. Rear-Engine Placement
Rear-engine cars are not a common sight unless you are on a racetrack. As the name suggests, in a rear-engine car layout, the engine is placed behind the rear axle. Therefore, the centre of gravity is behind the car.
A notable example of a car with this layout is Porsche 911. Another would be the Škoda Rapid, curiously nicknamed the ‘poor man’s Porsche’.
Pros of Rear-Engine Mount
The physics behind this placement is simple. It gives a car the handling benefits of a rear-wheel-drive while maintaining a weight distribution similar to a front-wheel-drive.
Professional race car drivers prefer this engine placement because it offers a better grip even in wet conditions due to the weight on the rear wheels.
This engine position also provides more power to the back wheels, and thus, makes a car accelerate quickly. It offers better tyre traction and handling as the weight bears down on the rear wheels.
Braking in a car with this placement is also improved. The weight over the rear axle counters the forward dip when decelerating, and as a result, the rear brakes can provide massive stopping power.
Cons of Rear-Engine Cars
Just like the other engine placements, this layout has its cons too. The most common disadvantage is its tendency to oversteer. Oversteering, aka fishtailing, happens when the car's rear end slides out of the front line due to the weight at the rear.
This vehicle dynamics is quite common in rear-engine cars, especially when going around corners.
Balancing such a car becomes a challenge. Early models of the Porsche 911 were nicknamed 'Widowmaker' due to their tendency to oversteer and cause spinning. Auto engineers counter this by putting a ballast at the front end of the car.
Conclusion
So which placement between the mid-engine and rear-engine offers better performance?
Between the two, mid-engine cars are the right choice for less experienced drivers. For the high-performance but oversteering-prone rear engines, it's best to leave them to more experienced drivers.
If you would rather have reliability and safety over performance, then choose front-engine cars. Besides, they have a setup that is easy to drive.
By Sam O.