Discussion in 'Hangar Flying' started by Malish, Jul 2, 2015.
Anybody knows about "EVANS" waterless cooling fluid? Is it good?
Has almost the same properties as 100% Ethylene Glycol which is much cheaper and available. Does not cool as well as 50/50 water and Ethylene Glycol. I ran it for a number of years in my aircraft but took it out and switched to 70% water and 30% EG. My temps dropped about 8C over the Evans.
I remember something about the viscosity difference supporting a different water pump impeller configuration in order to get the flow volume up. Can you confirm/refute this?
Very thick when cold but the stock pump in the Subaru seemed to work fine. Little different than running straight Prestone Ethylene glycol in any case which gives the same freezing, boiling and corrosion properties as Evans which is straight Propylene glycol. You'll need a larger rad to hold the coolant temps down to the same level as an EG/ water mix though as they state in the literature.
The stock coolant pumping rates for most auto engines is way above the requirement for typical aircraft use.
I used it in several clients aircraft when Rotax recommended it. Temps ran almost 50 degrees F higher. I stopped carrying it when I found out it was actually flammable. The other thing I didn't care for: Say you fly cross country and find you need to add coolant enroute. You'd better carry Evans with you, or be ready to flush the entire system if you add any water.
Interesting. PG is sticky, gooey, messy stuff. I wouldn't want it in an engine compartment.
I remember when Evans was running SCCA GT-1 Camaro test cars. The way it as originally designed to be used was reverse flow and with no pressure cap. They wanted the engines to run hotter. They were always fast.
Evans has done a good job marketing the stuff but the fact remains, it's characteristics are nearly identical to undiluted EG except that it's not toxic like EG if ingested. A boiling point of 375F is irrelevant for most IC engines since they would melt or seize long before this point was reached. Pure glycol of any type is inferior from a heat conduction standpoint to water/ glycol mixes no matter what anyone may claim. Enough people have compared it back to back with conventional mixes to know the truth but even the published specs confirm this.
It's been pretty well proven on dynos that engines make more power if the coolant temps are kept lower anyway.
Pure glycol can help prevent boil over in extended ground running if you have a poor radiator design as many liquid cooled aircraft have but I'd be concerned running engines over their design temperatures, even at idle. Best to change the rad design to fix the problem properly.
Just some historical perspective; I'm not interested in using it. It was back in the day of carbed engines and I think they were running way north of 14/1, I'm remembering 16/1 for some reason, compressions when everyone else was at 12/1. I think they were running coolant at 300 F. Dont know how many engines they ate up if any, but they were always close to winning the runoffs. Black Camero. I think they were always looking for an OEM deal and when Chevy started building reverse flow Corvette engines and the stuff did no magic in them, they were done.
Reverse coolant flow with super high CRs (higher peak chamber pressures and temps) would make sense using pure glycol since it has poor thermal conductivity. The same things could be achieved with EG and reverse flow so any advantages are due to layout and not the Evans per se. There is nothing magic in the Evans coolant.
Today, many race engines run over 14 to 1 with conventional coolant and water flow paths. In fact, some production car engines now are in those ranges. MAZDA: SKYACTIV-G | SKYACTIV TECHNOLOGY
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