I didn't crunch any numbers in my decision to use this Laminova heat exchanger, I only knew that in climb and level flight I had different cooling between oil & water and figured I could balance it out with this heat exchanger at a small price in weight. It certainly doesn't increase the cooling of the system as a whole.
It should be pointed out that these are not coolers, only heat exchangers. So if a oil/water cooling system doesn't have adequate cooling to begin with, then this will do nothing to address that.
In my case I found that I could climb from 2000' ASL (field) to 10000' ASL in 3 minutes before my coolant temps hit redline, but I still had plenty of room on my oil temps. In level flight my coolant temps would drop but my oil temps would slowly increase to redline. So I figured this would help me borrow from Peter to pay Paul. It still didn't address cooling shortfalls properly.
I believe the biggest culprit in this was the shape and position of my oil cooler inlet which was form over function (hey, it looked good).
Now I have made a lot of other changes which hopefully should address improper cooling airflow. As well as reshaping the oil cooler inlet duct I also did outlet ducting for the oil cooler, intercooler and right coolant radiator. I did not build a outlet duct from the left radiator due to it's close proximity to the turbo exhaust pipe. This interfered with the space required for a proper exit duct and I figured it probably would be a good idea to have some airflow over the turbo. Previously I had only ducted my inlets and left the air to find it's own way out of the cowl through what I believed were adequate sized exits. Ed Anderson spent a lot of time researching cooling air flows and finally was able to beat it into me that exit ducting is every bit as important as inlet ducting.
The other change I made which I hope will have a significant effect is I bought a new set of deep pitch blades for my IVO prop. I also cut it down from 76" to 70". This should give me a higher cruise speed with the accompanying increase in cooling airflow with the same RPM.
So with all these changes it's unknown if this Laminova cooler will have any benefit but I'm certainly not going to remove it as it it's only cost at this point is a few pounds which if I need to get rid of that I'll just start jogging again... not a bad idea anyways :-)
As a side note to these observations there is something to be said about overcooling the engine oil. (i.e. cooling the oil too much at higher altitudes or in cold conditions.)
An oil-to-coolant system help to moderate that scenario.
T Mann