Keep her above 4000rpm and she'll thank you for it every day.

[mquillen]

Although carbon build-up isn't good, I suspect another reason (perhaps the primary reason) for the advice to keep the revs up was the fact that all of the early Porsches were air cooled. Keeping the revs up meant airflow--lugging an aircooled engine is the fastest way to kill it.

[MNBoxster]

Originally Posted by mquillen

Although carbon build-up isn't good, I suspect another reason (perhaps the primary reason) for the advice to keep the revs up was the fact that all of the early Porsches were air cooled. Keeping the revs up meant airflow--lugging an aircooled engine is the fastest way to kill it.

Hi,

You make an excellent point!...

Happy Motoring!... Jim'99

[70Sixter]

It was originally mostly a spark plug fouling issue. Before CD (in 69?) fouling was a major problem. Could happen in minutes, especially in traffic. Some people even put hotter plugs in for city driving and switched to cold ones for open road/track. We all tried to use Amoco Super Premium because it was the only lead free gas.

Low rpm carbon deposits can form around the top of the cylinder and the results can be disastrous after years of build-up when a trip to redline "stretches" the rod & piston into collision with the nasty carbon.

[blue2000s]

There are also mechanical (inertial) reasons to keep load down at low rpm. In general it's a good idea to keep in the higher rev ranges if load is going to be high. This is generally when you feel the need to "floor it".