I think, for racing applications, Nikasil is probably yesterday’s news, at least for some applications. As cylinder wall hardness approaches 270-280 Bha on some compacted graphite blocks there just doesn't seem to be any use for it.
Better control of ring land size and finish are also major...
It would appear that if the cylinders material is of sufficient hardness then coatings don't offer any significant benefit. That being the case, a clean "base metal" finish would be desirable, one that is the optimal roughness and texture for the ring design and piston skirt being used.
Steve
