Sorry to say your basic physics is way off.
OK, lets park that for now.
If you increase the flow rate, yes there's less time for each unit volume of water to heat up, but then as soon as it flows away it is replaced by another fresh unit volume of cooler water that has a lower starting temp as it hasn't just been heated partially by the supercharger. Since heat flow is driven by the temperature delta between hot and cold, a plentiful supply of colder water is better. Think of it like having an infinite reservoir of cold water.
All true of course. However, you've overlooked a key factor - if the rad hasn't been able to cool the coolant effectively enough, because the coolant's been pumped too quickly through it, that "fresh volume of cooler water", won't be very cool at all. It could be of a very similar temperature to the coolant that exits the supercharge, in fact. In this example, the efficiency of the charge cooling system will be reduced and boost will be bled off and timing pulled.
But I tried to explain that in my 2 previous replies...
Regarding number of passes, the only thing that determines the amount of time the water stays in the radiator core is the flow rate which is defined by the pump. If it flows 1 litre per second, it doesn't matter how many passes there are, the water will flow through the rad at 1 litre per second. You can have one pass at low speed or four passes at high speed but one litre flows through the rad every second - except that the more passes, the greater the flow restriction and the less efficient the pump and so actually you end up at 0.95 litres per second.
Yes, mostly, except to be pedantic, flow rate is dictated by the pump. And the capacity of the core also affects the length of time a measure of coolant will stay within the core. Again though, you've missed the salient point. That being - the more passes a measure of coolant has through the core, the greater the cooling effect will be applied to it, all other variables being equal. Ergo, for a given measure of coolant, at a set flow rate, a specific starting temperature and given volume of air flowing through the core, the coolant that exits the 4 pass cooler will be at a lower temperature than that which exits the single pass cooler.
The main reason to add core passes is to increase the core's efficiency and effectiveness, as we know. Although, the more passes, the greater the volume of coolant required to fill the system, which has the benefit of giving the system a higher specific heat capacity. And this gives the benefit of a lower flow rate through the core being required, for the same level of effectiveness as that of a system with a lower volume of coolant. All other variables being equal. But again, I tried to explain that in the reply above...
As for the mixing of coolant and specific heat capacity, I can tell you that water has a better specific heat capacity than coolant, and so the closer you are to 100% water the higher the specific heat capacity. I have a feeling it's actually a linear scale proportional to concentration.
Well (fresh) water has the highest specific heat capacity of any liquid, Ammonia aside. But you'd not want to put Ammonia in your coolant system, would you?!
I'm not trying to antagonize, I'm just using my brain and my degree in physics to question what I have seen written. In my experience, those who excel are those who question the perceived wisdom.
Antagonistic no. Condescending yes!
I don't have a degree in physics but, I can honestly say I've not found that a hindrance to my life up until this point and I don't think it's particularly necessary to understand these simple concepts either.
I actually haven't seen anything that resembles empirical evidence of the superiority of any one system over another, including the merc racing core.
That's probably because it doesn't exist. However, there is plenty of well thought through testing and reported results out there for the various aspects of an upgraded charge cooling system for this platform. And as mentioned above, it's not a complicated concept, as such a bit of intelligent thought will lead you to which system should work best.
Paul