The 991.2 Turbo and Turbo S still use a 9A1/MA1 use the MDA/MDB engine rather than the 9A2 found in the 991.2 Carrera. The 9A2 has PTWA cylinder bores which seem to have solved the bore scoring issue. Did the 991.2 Turbo get PTWA/SUMEbore or does it still use Alusil? I found one forum comment saying so but would like a proper source or expert opinion.

I ask because I was looking at getting a 991.1 Turbo S but both cars I had PPIs on showed bore score. The first has about 60,000 miles and showed moderate scoring in cylinders 1 and 3. The second car has about 50,000 miles and showed light scoring in all six cylinders. The cars are at non-Porsche dealerships and neither are willing to reduce the price much if at all. One simply told me that someone else will buy the car not knowing about the bore score.

Some shops I spoke to said all 9A1 Turbos will have some amount of bore score while on this forum people peg the incidence rate as somewhere between 0.5% and 5%. Based on my own samples the former is more statistically probable but I'm not inclined to believe most cars are driving around with asymptomatic scoring. Nevertheless, I don't want to waste any more time and money on $1000+ PPIs so would personally like to avoid any Alusil engines.

 

I thought the 991.2 Turbo/S were MDA and MDB engines.

 

Ah yes I'm totally wrong. So 991.1 Turbo has MA1 while 991.2 has MDA (Turbo) and MDB (Turbo S). It seems a replacement MDA engine has a part number starting with 9A2 but a lot of the individual parts are still the same as the 9A1. So my question is still open if anyone can shed some light: Which engine is the MDA based on and which cylinder bore surface was used?

 

Gen 2 991 turbo and turbo s have Sumebore coating. Big improvement. Not many people know this but the GT2 RS engine is based on the gen 991 turbo s engine so still bore scores according to Top Auto Nick!

 

https://www.pca.org/news/bore-scoring-how-to-prevent-it