How often to change oil?

[JFP in PA]

Originally Posted by madmods

Those Q's shouldn't be allowed to be asked online in all honesty! Anyone concerned with oil change, who don't know when to change it, should really speak to a track/team side support engineer or the team manager if possible. He/she will simply ask you: "tell me how you drive your porsche, and at what outside/engine temp, and I will tell you when to change your oil".

Actually, there is a technically based method to determine when to change your oil, regardless of what oil you use, or how or where you choose to drive your car.

Collect both new and used oil samples and send them out for analysis, being sure to request TBN values. When your used sample’s TBN has reached 50% of the virgin oil, it is time to change. Interestingly, as long as your environmental conditions and driving habits remain reasonably constant, this will happen in a fairly narrow mileage range. If you track the car in the summer months, but not in the winter, you will end up with two mileage ranges, one for each season; but they will be both accurate and based upon facts, not opinions..........