[RKDinOKC]

They went thru several iterations to try to solve the 928 oil issues between both the oil getting thru the crankcase vent, high rpm starvation, and GTSs just plain burning oil.

People tried dry sump systems with mixed results.

There was one solution that used the smog pump to put a slight vacuum on the crankcase both sucking oil from the heads and keeping the crankcase from venting thru the intake. It however still had a catch can for oil.

There was another system that drilled holes in the heads to drain them back into the oil pan specifically to address the heads filling with oil.

There were several different baffle designs on the factory baffle for the crankcase vent. Most were a big improvement. The factory baffle was just a plate with louvers to keep oil from splashing directly into the vent.

Then they discovered most GTSs Porsche did not drill the relief holes to the inside of the pistons on the oil scraper ring groove. The GTSs were notorious oil users. There was no place for oil from the cylinder walls to go so extra oil that was scraped got burnt. Especially the more wear there was on the rings, the more oil got burnt. If you thought your under warranty GTS was using too much oil, Porsche replaced the motor with one that had the piston oil scraper ring communication holes drilled.

That is why I had the oil passages drilled on the pistons of my GTS. That combined with new rings (there was no cylinder or piston wear), cured the oil usage on my GTS.

They also discovered that if you added 1/2 inch to the depth of the oil pan it would increase the oil capacity enough it would let the heads fill, then pressurize and push the oil on thru getting enough oil back to the pan that the oil pickup did not get air and cavitate the pump.

The GTSs already have a baffled oil pan that keeps horizontal G forces from letting the oil pickup cavitate.

So my GTS has improved vent baffle, drilled pistons, and the deeper oil pan.