I've red all threads about pistons here, used "search" button many times. But the question is still actual:

is piston # 11257576973 forged?
where can I find some document that proves that it is forged or cast?

 

Does anyone know the alloy used?

 

Yes
i found that out contacting my local mini dealer

 

Happy motoring

 

Be useful and write the answer SMH

 

MCS are cast, JCW are forged with lower compression.

 

Can you provide documentation that they are forged? I've just never seen it. And people swap out the stock pistons with forged ones from CP, Mahle, etc, so if they are already forged why do this?

 

From
This forum and experts I talked to prior to my engine rebuild the factory built JCW had forged pistons. The MCS was Mahle cast. They are a harder piston material but more prone to cracking. I went with CP because I had a dead hole already. The CP set were less than Mahle and I didn't want to mortgage my house to buy a real JCW set

 

Both MCS and JCW are pressure forged pistons. A true cast piston would not survive for long in a turbo application where the effective compression ratio exceeds 15:1. Both are made by Mahle using the same M142 alloy. The difference is in material thickness. Even CP are pressure forged just with more material, a more durable alloy and a better design IMHO. An actual full billet forged piston would be cost prohibitive.