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WERK I WERK I is offline
Forced Induction Junkie
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Join Date: Jan 2003
Location: Wisconsin
Posts: 3,291
STP as an additive in 930's.......observations

I've been meaning to report this for months, but moving and a new job had shifted my priorities somewhat.

Last year I thought with the lower Zn and Phosphorous in today's oils, adding the STP oil treatment would be an easy solution in adding those additives in my present oil. Valvoline VR-1 was the oil of choice and had been using it for about two years with no obvious issues.

After one season of driving with that combination, I would strongly advise against anyone using STP as an additive in a turbo Porsche. I use an inline filter (Canton) between the turbo sump pump and the oil tank and found the filter media to have a very noticeable presence of coke particles that weren't present in filter changes before. I can only surmise that the STP is causing the coking since my driving habits hadn't changed in that time period.
Sorry I don't have photos..................I'll find that damn camera in one of those boxes one of these days!

I have abandoned the "dino oil" ship this year and started using a 50/50 blend of Mobil 1 20-50W and Mobil 1 V-Twin with NO additional additives.
'85 930 Factory Special Wishes Flachbau
Werk I Zuffenhausen 3.3l/330BHP Engine with Sonderwunsch Cams, FabSpeed Headers, Kokeln IC, Twin Plugged Electromotive Crankfire, Tial Wastegate(0.8 Bar), K27 Hybrid Turbo, Ruf Twin-tip Muffler, Fikse FM-5's 8&10x17, 8:41 R&P
Old 08-05-2010, 06:23 AM
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