Originally posted by ALLAN:
boosted, what is the evans coolant? can you run it without their thermostat? maybe ill use that in my cars out here also.
Evans coolant, which goes by the name "NPG+" is a recent reformulation of the "NPG" coolant that has been used by WRC rally cars for some time now. The rally teams began using it some years ago because NPG allowed them to run non-pressurized cooling systems so that if a hose burst between stages due to a rock puncture or similar road hazard, it could be duct taped up and the stage could be completed. What they later learned was that the NPG coolant also was more thermally stable than the standard stuff and did a better job of removing heat from the cylinder head. As a result, they were able to save weight by running smaller radiators (or, making more room for bigger intercoolers) and still achieve better cooling.
NPG stands for
Non-aqueous
Propylene
Glycol and is a slightly more viscous coolant with different thermal properties than conventional ethylene glycol and water based coolants.
The benefits of running NPG+ is that it has a much higher boiling point than conventional coolant 50/50 mix, or even the pure water and Redline Water Wetter mixed used by a lot of racers. Whereas the boiling point of regular coolant is 250 degrees Fahrenheit, NPG+ won't boil until 369 degrees Fahrenheit.
It is thermally very stable. What this means is that while it takes longer for your car to warm up when you first start it -- especially when using a low temp. thermostat as is recommended -- the temperature fluctuations are dramatically reduced. I can drive my car as hard as I want, and never see the kinds of spikes in coolant temps. that I did running fresh Toyota coolant 50/50 mix and Water Wetter.
NPG+ also tends to resist cavitating in the water pump as well, thereby reducing the onset of bubbling coolant and hot spot related detonation.
Because it does not contain water, it will not corrode the pump, radiator and other cooling components like water based coolants will and can be left in the system indefinitely (never needs to be changed).
Whereas NPG used to require running a special water pump and other hardware from Evans, the reformulated NPG+ can be run with a standard pump, radiator and pressure cap and requires only a change to colder thermostat.
Oh, it is also non-toxic and environmentally friendly, for those that care.
That's the good news. The bad news is that it is incompatible with water or conventional coolant. This means install is a bitch, to say the least. It took us over 6 hours to perform 4 complete coolant flushes with Sierra coolant (a compatible coolant used for flushing) to eliminate the every last trace of conventional coolant and water from the system. You have to drain and flush the engine block, heater core, radiator, overflow tank, coolant passages and every other nook and cranny in the entire car before this stuff can go in.
It is also expensive, at $25 a gallon (and remember -- you're not mixing it with water so its $25 a gallon until your whole system is filled to capacity). However, once its in, you never have to change it.
It also will cause your car to run hotter than normal. I know this sounds bad and completely counter-intuitive, but the coolant is actually doing a better job of removing heat from the cylinder head even though the temp gauge shows that you are running hotter than normal.
It requires a low temp thermostat to bring the temps down to closer to stock range, and like I said above, will build up heat a little slower than conventional coolant so it takes a while longer than normal before you can start driving your car hard.
If you're running a high pressure radiator cap, you will need to ditch it and go back to stock. NPG+ prefers zero to stock (low) pressure and expands and contract more dramatically under pressure than conventional coolant.
I have personally been very happy with the consistency of temps I am seeing with this coolant and with the peace of mind I get from knowing that I am putting less wear on my cooling system by running less pressure than I had been, and that this stuff will not boil and cause me to lose an engine until well above the range at which regular coolant would have already been past its operating parameters.
I think that pretty much covers it. Let me know if there's anything else you would like me to add.
Also, there's a lot more useful info here:
http://www.evanscooling.com/
-- DavidV
www.boostedgroup.com
[This message has been edited by BoostedMR2 (edited 30 August 2002).]
