Lee emailed me and said he's not coming back on the forum. He sent me a list of things to try.
Here's what he said:
One change at a time. Get a note pad and log results under various conditions after making one change before you make the next change.
What's relevant is the temperature in and out and I saw you bought an inline gauge.
The highway and off ramp temps are what I would want to see most.
Log the date, air temp, gauge temps (at idle, 10-20, 30-40, 50-60), distances traveled at respective speeds and any changes observed within those speeds.
The cooling components fan claims 2,500. You spent money on this product so use it.
That shroud is trapping air at higher speeds and then not recovering I am not sure its the root cause but its not helping and your description sounds like trapped air flow and heat soak
Remove the shroud. In this scaled illustration the black is flush against the core and in the grey area, the air has to pass in a ~7/8” gap around the ~1” solid ring supporting the blades. Your temps are okay around town but climb on the highway this will help on the highway and you'll have to see how it does around town. You may be able to run one fan
If that reduces your temperatures enough for highway and town, then stop. If it gets you lower and you still want more, then put the SPAL pusher back on in an offset position. The yellow gives you 1,959 cfm. The green claims 2,500 cfm, the blue area is the combined cfm (not literally). This will help on the highway and this will help it recover (from what I hope is an already lower than 205 temperature from getting rid of that molded plastic).
The only other suggestion I would make is two SPAL fans. I would NOT go this route I tested step 3 and step 4 because of the incremental cost
they're better quality.
the combined stated cfm is lower than the two you have now but I believe it to be closer to reality.
the motors have smaller diameters to impede air and the vanes and finger guards block less air than the flex lite you had and the cooling components you bought.
I recall you said the hoses had not collapsed. Check your coolant flow with thermostats open and higher rpm. If its not pumping enough you may want to check your pump impellers condition and design. The guys who mentioned the fallacy of fluid too fast are correct - there is no such thing. The oe pumps used cast impellers. The casting is thick and they have a reduced eye which results in reduced volume. The vanes are not tall and this too reduces the flow. I have seen worn vanes and you should look for evidence of cavitation e.g. pitting and tip wear if you don't have flow.
Regarding your coolant composition.
Water has the best specific heat value to shed heat.
Ethylene glycol and propylene glycol have engine preservation properties and raises boiling point but lower specific heat. Specific heat is the amount of heat required to change the temperature of a mass unit of a substance by one degree.
You're using 20/80 propylene glycol at 328' elevation and have a 7psi cap I expect you'll boil at 233 deg. You are running at 205 on the highway so boiling is not a concern but specific heat is.
Tap water may have minerals and create scale so use a premix or distilled water.
