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Speedy Squirrel Speedy Squirrel is offline
Rocket Scientist
Join Date: Jun 2008
Location: Detroit
Posts: 906
Here is a page of your owners manual which you really should read. You will find that, even in 1989, Porsche was switching to synthetic oils. The grade of oil specified in 1989 was API class SF. In 2014 we are up to SN, vastly better performance in the same standardized tests.

Oil is a marketing game, and in 1989 Shell oil was the official oil of Porsche. Around 1995 Mobil 1 became the official oil of Porsche, and remains so to this day.

Modern synthetic oils contain Zinc and Phosphorus (ZDDP) compounds at adequate levels to vastly exceed the anti-wear capabilities of the original fill oil for your vehicle. I use Mobil 1 15W-50 advance full synthetic. It is specifically recommended for high performance engines with non-roller camshafts (such as your engine). The technical data for this oil may be found here:

There are two areas where synthetic oil is critical, turbocharger seal ring and piston oil cooling jet. Both of these items are adversely affected by using conventional oil. Conventional oil contains a number of short chain hydrocarbons that quickly oxidize into carbon. The carbon deposits may jam the turbocharger turbine oil seal ring, and clog the piston cooling jets.

Old 01-18-2014, 07:58 AM
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