quote:
Originally posted by Ugly3:
Please cite your sources for this. I have seen no comparative data that suggest there is much difference between synthetics and conventional oils.
I am startled that after thirty years of SAE papers and manufacturer studies and tests, the complete elimination of mineral oils in racing and high-performance street cars, and trillions of miles real-life demonstration, you've never seen comparative data that even "suggests" there's much of a difference.
The evidence that Mobil provided is so old that most of it is out-of-date, since the industry doesn't see it as an open question. However, Mobil still summarizes the results of the decade-old comparison:
http://www.mobil1.com/index.jsp
Q. How do the results of 200,000-mile engine testing of Mobil 1 compare with a conventional motor oil?
A. Over the years and through several generations, Mobil 1 has been tested under the most grueling circumstances imaginable. Each test yielded confirmation of the incredible performance of Mobil 1. And each evolution has made Mobil 1 even better.
One such test compared identical 2.3-liter four-cylinder engines run for 200,000 miles – one using Mobil 1 5W-30 and the other using a premium brand 5W-30 conventional oil. There were some interesting results:
Engine wear rates were higher for the conventional oil than for Mobil 1.
The conventional oil produced heavy varnish deposits, while the Mobil 1 engine was virtually clean.
The conventional oil consumption was eight times higher than that of Mobil 1.
While Mobil 1 remained at the SAE 30 viscosity level throughout most of the test, the conventional oil showed rapid degradation, with viscosity increasing into the 15W-40 range. This obviously would adversely affect any fuel economy benefits.
Keeping in mind that these tests were conducted with earlier formulations of Mobil 1, ExxonMobil® engineers are confident that Mobil 1 with SuperSyn™ will provide even greater protection than its predecessors.
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Other synthetic manufacturers have reported similar findings over the years, both in field tests and in racing, where synthetics replaced mineral oils decades ago.
SAE papers that are relevant and still available would include:
740120 : Synthetic Engine Oils--A New Concept (02/01/1974)
821238 : Friction, Wear and Blending Benefits of Dodecanedioate Diesters in Automotive Lubricants (02/01/1982)
850564 : Synthetic Lubricants for Passenger Car Diesel Engines (02/01/1985)
871273 : Synthetic Automotive Lubricants--Performance and Protection (03/01/1988)
952553 : A Synthetic Diesel Engine Oil With Extended Laboratory Test and Field Service Performance (10/01/1995)
981444 : Advanced Synthetic Passenger Vehicle Engine Oils for Extended Oil Drain Performance (05/04/1998)
2000-01-1993 : Performance of An Advanced Synthetic Diesel Engine Oil (06/19/2000)
Of course, mineral oils are still sold and have been greatly improved over the years. Except for use under severe conditions (e.g., racing) or very long mileage (truck fleets for example) the difference in wear rates may not be meaningful.
