For many Porsche enthusiasts, a “real” Porsche has to be air-cooled and it is not negotiable. The air-cooled units have been favoured for multiple reasons, but mainly for their hairy and involving character that you cannot find with the newer water-cooled designs.
For vintage motorbike riders, or car drivers familiar with this type of design there is no need to convince them about the benefits of newer water-cooled units. They will probably tell you that “it’s all about the character, and experience” and they are definitely right. In terms of cooling efficiency, it is admitted that the older technology is far less efficient at cooling your powerplant than the newer one.
The Porsche 911 air-cooled era started in 1964 with the 356 4 cylinder 1.6L engine which was used in the 912. At the time, it offered a decent 90hp output but could be considered pretty slow by today’s standards (basically a Beetle engine).
The 2.0L flat 6 version offered in the 911 developed 130hp in its initial configuration and was upgraded in 1966 in the 911s to increase the power to 160hp. Quite a significant move from the initial 90hp flat 4. However, air-cooled engines found their limits with cooling as power increased over the years and development, and Porsche recommended to add external oil cooling through exchangers if the car was to be used for racing purposes, and ultimately a front cooler became a standard for Porsche cars.
After years of development and improvements, the air-cooled units reached their peak with the type 993 which was produced from 1994 to 1998 and the 3.8L engine that could produce up to 450hp on the Turbo S and the GT2. This is one of the reasons why the 993 became so desirable among the Porsche community. After that, the 996 generation arguably became the subject of controversy for being the first water-cooled 911.
In more modern applications, BMW still used an air-cooled flat twin engine for its best selling motorcycle, the R1200GS until 2013 where its water-cooled replacement debuted, causing a lot of raised eyebrows and controversy in the BMW Motorrad community. But given the increase in their sales figures it probably was for the greater (BMW’s?) good.