In Reply to: guys/gals, a quick question re synthetic oil (m) posted by from e46 board on December 13, 2000 at 15:37:14:
However,I recall reading a Consumers Report on oil sometime over the last 1-2 years. They blueprinted engines on taxis used in NYC and compared differnet oils including synthetics. Pretty rough driving conditions with 24 hour operations with stop and go with quick accelerations at times. Their finding was that dirt causes wear. If you changed the oil and filter at reasonable intervals (they recommended 5000 miles) you should not have significant wear. They also stated that oils with similar SAE ratings should perform similarly.
Now this must be compared to the Mobil Oil BMW 3series car. Mobil blueprinted the engine, drove the car 1 million miles (not just on the Dyno; they drove it cross country a few times i.e.from NJ to Arizona for a car show as well as around town locally in NJ) and measured the wear after the million miles. They found insignificant, very minimal wear on the engine. Although I do not recall what the oil service interval was, this is a strong argument for synthetics.
I think it does not matter which oil you use and it is a personal perference but the key is to change the oil and filter often, maybe every 3-5000 miles. I use every 5000 miles since it is easier to remember.