High-performance vehicles, like everything that Porsche has to offer, rely on advanced cooling systems to keep their engines from melting. Broadly speaking there are two ways to cool an engine, these include air and water cooling.
Today, most vehicles are water-cooled as this leads to efficient heat absorption, more precise control over the engine’s operating temperature, improved engine longevity, and quieter operation, water-cooling systems are designed to be environmentally friendly. They can help reduce emissions by ensuring the engine operates at an optimal temperature, which can improve combustion efficiency, there are of course many other advantages. However, Porsche resisted the switch from air cooling to water cooling for a long time, making it much easier to find an air-cooled Porsche than other vehicles.
Let’s take a look at the history of air-cooled Porsches.
What Is Air Cooling?
Engines generate a lot of heat, especially as they increase their speed. Engines need to be cooled efficiently and continuously, or they will overheat and break. For this reason, car manufacturers engineer different ways of cooling engines by moving excess heat away from the engine to allow it to maintain a more consistent temperature.
Air cooling is the oldest way of cooling an engine. Porsche designed its vehicles to take in a lot of air while they move and blow that air past the engine. As they travel by the engine, that excess air picks up the excess heat from the engine and moves it away as it is blown out of the car.
This is exactly how a fan keeps you cool: it blows air over your skin to pull excess heat away from your body.
Why Switch To Water-Cooled Engines?
Air cooling is an effective way to cool engines, up to a point. When temperatures rise too high, a more efficient way is needed, which usually means switching to water cooling. Instead of the air blowing past the engine, water coolant is used instead. It is a more efficient way of extracting excess heat faster. That coolant can also handle a lot more heat with fewer problems or need for repairs.
Just like air, the water is circulated around, sometimes through the engine to absorb heat. Then, it is pumped away from the engine to transfer that heat somewhere else. Ironically, the air cooling method is often used to cool coolant outside of the engine.
Water cooling is better for engines that generate heat above a certain threshold. At some point, air cooling may not be enough to keep the engine within a certain operating temperature range. The need to switch from air cooling to lwater cooling largely depends on the performance specs of the engine.
When Did Porche Switch To Water Cooling?
Porsche resisted switching to water cooling until 1998. The last air-cooled vehicle that the company made was the Porsche 911 993, built in 1994-1998. The company switched to water cooling when developing the Porsche 911 996, greatly extending the lifespan of this luxury vehicle.
Why Didn’t Porsche Want To Change?
Porsche was reluctant to change to water-cooling systems because it meant a significant change to the overall design of its vehicles. Air cooling systems are relatively simple. They require few parts and can be integrated into a vehicle design easily. Liquid cooling is more complicated.
To apply water cooling to an engine, the vehicle needs several additional parts added, including a radiator. This extra weight meant reduced performance unless engines became stronger to compensate.
water-cooling systems are also more expensive to use since they require special design chances and more parts.
The Impact On Porsche’s History And Value
Being the last vehicle to use an air-cooled engine in a brand means that it is highly sought after. This is definitely the case with the Porsche 911 993. In fact, it is so sought after that Porsche decided to make one more.
It is not unusual for car companies to keep extra production parts from the original run of a car in their warehouse. Porsche had one extra body for the 993 and decided to rebuild one from the ground up. It was first seen at the Rennsport Reunion, a big car meet for Porsche enthusiasts. It is officially the last of the air-cooled 993s ever made by the company.
Where Air-Cooled Engines Shine
When Porsche finally began building cars under its own brand, the company adopted air-cooled engine designs for a variety of reasons. Besides being easy to maintain and able to withstand winter weather, air-cooled engines sounded better. Porsche designed them with a distinct, full-bodied sound that is next to impossible to recreate with water-cooled engines.
Water coolant and the components needed to run them absorb a large part of the sound made by their engines. Air-cooled engines are free to roar unimpeded. This gives many Porsche models a unique sound that was a trademark of the brand during that era.
The End Of Air Cooling Systems
Despite Porsche’s desire to hold onto the air cooling system, it had to make the switch. The problem is that water cooling is far more efficient, and the increasing power output of engines meant that efficiency became more important than tradition. Porsche, always wanting to stay ahead of the competition, made the decision to switch to liquid cooling to make sure that its engines could reach the high power-output numbers needed to keep up with other companies.
Over, But Not Forgotten
Porsche may not make air-cooled vehicles anymore, but the legacy of these vehicles has not been forgotten. There are several still on the road, or that can be found at car shows. Porsche also has them in its museum. Many other design features have carried over from all of the vehicles with air cooling, keeping Porsche ahead of the competition.