I work for Evans and do the tech and answer many questions. We have different coolants for different applications. When some calls, I pick their brain on what they are putting it in. Alot depends on the radiator they are using.
Our coolant has a viscosity to it. The NPG+ is that of a 10wt oil , about the same as 3 in 1 oil. It works well in aluminum radiators because they have wider tubes than a copper/brass. Most copper brass tubes are 3/8" wide and since our coolant is based on volume and flow, with the smaller tubes the motor may run warmer due to lack of flow capability.
The NPG-R is the thinnest in viscosity and is about the same as straight antifreeze out of the jug. It works well in copper brass or aluminum.
Our coolant does not allow the steam vapors to occur in a motor. What they are .....when a motor builds heat and the internal metal temps climb, they turn a 50/50 mix to pockets of steam. The steam cannot recondense fast enough back to a liquid to absorb heat and take it to the radiator to cool it.
Since ours has a boilng point of 375 degF, ours stay a liquid all the time and remove heat from internal metal. Now with that said....you have to realize that most sending units for the temp gauge is on the front of the manifold right near the top hose outlet, so withn the coolant containing more heat it will be picked up by the sending unit and you may see a higher temp on the gauge. BUT!!! internally the metal is much cooler.
To prove this I did have a customer call me from Calif. I told him all about what our coolant does and do not expect to see lower temps. He had a 1100 hp blown/inj Arias motor in a 32 roadster. His temp gauge reads 225-230 with a copper brass radiator. So I told him to put in the NPG-R.
he called me back 2 wks later and said that what I explained to him, he just proved. He had the car out on a 90deg day. The temp gauge read 230 and he had no problem know what I told him and how the internal metal temps where much cooler than the gauge read. He took the car home and with a digital temp gun , motor running , gauge reading 230, he went over parts of the heads and block and got readings of 180-195. So he proved my point and was very satisfied.
if anyone is interested in using our coolant ,I would be happy to talk to anyone and answer any questions. .