automationgame.com

As one might infer from the title, I'm wondering how I can determine the total cost when building engines in sandbox mode. In scenarios, this value is displayed, but in sandbox I can only see the material cost and man hours. I would like to be able able to compare costs across various engines, total cost would make this much easier.

You can determine that cost by waiting for the next patch... where that issue is a non-issue.
There will be shown both total cost and manhours, instead of material costs and manhours.
A manhour is either 15 or 20 dollar right now - don't quite recall. You can check that yourself if you do some maths

Heh, ok, thanks. On a related note, is the emissions figure convertible into a real-life measurement? In my pursuit of realistic production engines, I want to make sure that they meet emission regulations for their year.

Nah, emissions are arbitrary values. They do not directly correspond to real-life figures, but should be correlated to them, of course.