All other things being equal, should the usage of aluminum for the block and head affect the emissions? For example, I have a 1970 V8 in the Sandbox: With a Cast Iron block and header, it generates 3840 emissions. When I change it to an Aluminum block and header (and no other changes) it generates 2845 emissions. Thus the aluminum reduces the emissions far more than changing Cast Iron pistons to Hypereutectic pistons. This is with the June 30th release.
If this is correct then no worries, but it seems odd to me, especially since previous versions of the Engine Designer had no change in emissions based on the metals used for the block and/or head.
I thought this had been in since long ago, but I could be wrong there. Yes, it is supposed to be that way. Reason: aluminum has better heat transfer than cast iron, so that the cylinder walls during combustion are cooler on average for aluminum heads as compared to cast iron heads. Hence, there is lower production of emissions for aluminum,