Originally Posted by jgrewe
Parallel, when you run them in series you lose the high temperature differential between the air and the oil after it goes through one cooler. That means the second cooler isn't doing nearly as much for you.
Is this really true? I did some back of the envelope calculations one time and IIRC everything pretty much ended up a wash (assuming that both coolers get the same airflow).
My experience with the coolers on my car (which are plumbed in series - that's the way the previous owner did it) is that I actually have problems getting the oil hot enough. The thermostats have been removed and I'm seeing about 160-170 at the pedestal on a hot day at VIR (H2O temps 200-210).
I always assumed that the bigger issue was that series coolers will drop your oil pressure more than parallel ones - essentially you have a larger flow restriction and thus get a larger pressure drop across them. I'm only seeing 40-50+ psi (again, with a pedestal sender), which is why I'm going to replumb it to a parallel system Real Soon Now (it's somewhere down there on the ToDo list
I know we've beaten this to death over the years, but is there any new data available from anyone?