I think you are incorrectly applying air fuel ratio figures and principles for gas engines to diesel engines.Mother Cummins already uses a similar system on 4Bta's bigger siblings. It is called Low Temperature Aftercooling (LTA) & it is in current use on the following engines QSK-19L & 23L big inline sixes, QSK-30L, 38L & 45L V12's, QSK-50L & 60L -V16's, QSK-78L V18. The LTA system has its own coolant pump, plumbing, thermostats and radiator. The reason it is used is for big power gains with predictable results. The trick here is to be able to regulate the air fuel ratio @ about 14:1 by weight(stoich) in the factory set up for effeciency and no smoke. This is the reason for the LTA thermostats; to regulate the LTA system @ about 130*F-160*F gives predictable air density at very different ambient temps and altitudes & actually heating the intake charge @ low boost/low ambient temps. The major importance here is to prevent a lean A/F mixture ratio and the resulting engine damage from a very cool (ie:dense) intake charge. This is likely no problem in Texas but here in Canada Brrrr. So Toolmans solution using ice @ the track is predictable and consistant and can be tuned. But some of the other unregulated system suggestions could be a bit expensive on a very cool winter morning!
AFAIK diesels don't run near 14:1 (stoich), and under light load are very happy to run much, much leaner.
But I don't know those bigger siblings, or the LTA system, and if there has been a big change to traditional diesel air fuel ratios bought about by new technology, then I want to be educated about it.