Two problems with this.
First of all, you think that there is a problem with CSSC not having the most efficient engine. Which, given Wartsila's long history, it's certainly plausible that it would have more efficient engine than CSSC. And this is CSSC's first crack at 9MW combustion engine. It is the best CSSC can do at the moment. If you have a problem with that, that's your problem. I'm kind of tired of your complaints on this and the aero engine thread. 46% efficiency is already really good.
Secondly, both the CSSC and MTU engine have engine speed of around 1100 rpm, whereas this Wartsila engine speed is 720 to 750 rpm. Given that the CSSC engine supports both diesel and ammonia, you should compare its diesel mode SFC to the DF version of Wartsila engine. So, you are not comparing apples to apples here. Even if they were the same, the difference between 176.5 g/kwh & 185 g/kwh really isn't all that much. You are looking at probably 46 vs 48% thermal efficiency. 46% efficient combustion engine is pretty good. That's where the top gasoline engines are at.
And if we look at it's ammonia mode.
1 kg diesel = 2.2 kg ammonia -> 2.457 kWh/kg of ammonia
each kg of ammonia has 5.17kWh of energy -> 47.5% thermal efficiency
So CS27 is even more efficient in ammonia mode than diesel mode.
CSSC designed CS27 to be an efficient "green" combustion engine that can fully explore thermal energy of ammonia fuel.