Curtis said:Nick Comstock said:I heard we were in here killing cats.
They taste great with some Evans marinade
Mama always said after the Killin comes the grillin.
Curtis said:Nick Comstock said:I heard we were in here killing cats.
They taste great with some Evans marinade
Mama always said after the Killin comes the grillin.
Curtis said:boxedfox said:Not recommended. Tried it on my old Nissan. Motor ended up running HOTTER after converting to it.
I later found out that Evans uses a high-concentration propylene glycol-ethanol glycol mix as its base. So in addition to having crappy thermal conductivity, it's super slippery (bad for auto-x or track use), and at the concentrations they use, is actually flammable. It's almost the same as running your car on 100% antifreeze, which is a terrible idea.
Evans uses just Propylene glycol, hence why it is called Evans NPG. It is only a tiny bit more flammable than Ethylene glycol; 700F vs 748F respectively.
Sierra is the regular "aqueous" propylene glycol coolant, for what it's worth.
Scuttlebutt from the RX-7 Mailing List (ok, i am old) was to drain the whole cooling system, blow out the heater core, refill with straight Sierra to collect the rest of the old coolant, drain that, blow out, etc., then fill with NPG.
Long story short, it is not the coolant's fault. If you approach Evans coolant from the angle of thinking it's a better coolant and apply normal rules of cooling temperatures, you'll always assume it is a massive fail. You have to re-write your entire thought process on how coolant works. It has nothing to do with the temperature, it has to do with heat transfer. It's just that at 230 degrees, regular water-based coolant starts boiling and loses its ability to transfer heat. Non-aqueous coolants don't have that problem. They still transfer the same amount of heat, just at higher temperatures. In the traditional sense it looks like it is terrible coolant, but it is a whole different paradigm.
If you approach it like the difference between R12 and R134, you'll realize that it makes a great coolant.... if the system is engineered to work effectively with it. It is not a plug-n-play coolant, but it is an excellent thing if set up correctly.
My grandfather used to replace the water in his 23 Model T with Kerosene for the winter. It still worked, it just smelled funny. (and it was also a rolling bomb, but that's beside the point.)
Knurled. said:Curtis said:boxedfox said:Not recommended. Tried it on my old Nissan. Motor ended up running HOTTER after converting to it.
I later found out that Evans uses a high-concentration propylene glycol-ethanol glycol mix as its base. So in addition to having crappy thermal conductivity, it's super slippery (bad for auto-x or track use), and at the concentrations they use, is actually flammable. It's almost the same as running your car on 100% antifreeze, which is a terrible idea.
Evans uses just Propylene glycol, hence why it is called Evans NPG. It is only a tiny bit more flammable than Ethylene glycol; 700F vs 748F respectively.
Sierra is the regular "aqueous" propylene glycol coolant, for what it's worth.
Scuttlebutt from the RX-7 Mailing List (ok, i am old) was to drain the whole cooling system, blow out the heater core, refill with straight Sierra to collect the rest of the old coolant, drain that, blow out, etc., then fill with NPG.
Correct. Both EG and PG are miscible in water. Both EG and PG have similar specific heat capacities. The only apparent benefit to PG is that it is non toxic. This conversation (in my mind) could be titled "can I run 100% anti-freeze?" As opposed to the Evans brand specifically. EG vs PG has little to do with this discussion, it's more about the benefits of running anti-freeze with water or without.
Nick Comstock said:Curtis said:Nick Comstock said:I heard we were in here killing cats.
They taste great with some Evans marinade
Mama always said after the Killin comes the grillin.
*no actual cats were killed in the making of these jokes.
Stupid jokes, what if the jokes were about your dog?
I'm going to get a parrot, name it Chaney, train it to tell jokes about duck hunting and offend everyone.
Green antifreeze kills dogs too..
Ethylene glycol antifreeze is a weird one. It's biodegradable, but it's also highly toxic to animals until it biodegrades...
Some animals.
Gotta give props to Curtis here for the science lessons. I had looked at this stuff out of basic interest, guess I'll keep it in the back of my head.
Also from an engineering side. at the elevated temp a non aqueous coolant can run with out having localized boiling in theory it should keep the temps from Rapidly running away however the parts it is cooling is still running hot. Fix that problem don't try to band-aid over it. In the 90's when hi HP litter sized bikes came around to the norm, when the coolant reached 255 it was norm for the bike to start smoking the next time it fired up due to ring loosing tension. Adding a coolant that doesn't boil over just means you don't have to stop due to boiling over but your still killing the motor... True the killing band maybe moved up some degrees but your still doing damage if your running hot. Fix the problem not mask the symptom.
Oh and PG coolants due work great they been in use in industrial apps for years HOWEVER in the past 8 or so year the prices have gone though the roof.... Why? VAPPING. 
Yup if you vape then you should know the "smoke" you exhale is PG, and some of it stays with you in your lungs.
44
"Smok'in the competition NOT Tobacco"
"Transplant organs, Don't bury them!"
So yeah it is a different approach to cooling, but 10 year antifreeze is readily available. I think that's pretty reasonably hassle free.
And let's not forget that just because an engine can tolerate running metal temps of 250+ degree, does not mean that it should be up there! All of the modern engines I've seen have been pretty rigorously engineered to run at 200-220 degrees all the time for power, longevity, and emissions. Pushing beyond that really puts you into unknown territory.
In reply to freetors :
Cup engines run a lot higher than that though. More engine heat means the combustion loses less heat to the cooling system, which means more power for the same fuel.
Watching WRC one time, heavily turbocharged high compression engines running endurance type loadings with poor airflow, they were monitoring coolant temps. They were okay with 120, 130, they got concerned. They shut it down at 145. That's about 250 as normal, 265 uh-ioh, 290 shut 'er down... And they run water or something close to it.
Higher heat is fine from a performance perspective unless the engine clearances are tight enough that the extra metal expansion at that temp causes issues or you end up driving intake temps through the roof. But where it causes issues is durability. Gaskets and seals get cooked faster (and this includes stuff like valve stem seals), oil will run hotter if you don't have an oil cooler, etc.
So outside of all out racing, IMO, the tradeoffs aren't worth it. If localized boiling is a concern, make sure all of the system components can handle it and then up the system pressure, as that will increase the boiling temp (provided there's a big enough temp swing from cold start to full temp under load to hit cap pressure in the first place). FWIW, factory system pressure on both of my vehicles is fairly high to cover potentially pushing the cooling system limits a bit. Jeep runs an 18psi cap (a lot of cars are in the 13 - 16 range), BMW cap is 29 PSI.
In reply to rslifkin :
That is radiator cap pressure, not the pressure in the engine.
Was having issues with an engine blowing things out a while back. Measured 120+psi in the block at about 2500rpm or so. (It had insufficient bypass area due to several factors) As a test, measured the pressure in a 3-liter pushrod Taurus. 45psi in the block.
To be honest, I have no idea how engines with suction-side thermostats even work. How do they build pressure in the cylinder head to keep the coolant from boiling around the spark plugs and exhaust ports?
I put 16psi caps on my cars which both originally used 13psi caps. Note that hose blowout frequency seems to increase exponentially with system pressure though, and it gets really bad above 18psi.
Knurled. said:In reply to rslifkin :
That is radiator cap pressure, not the pressure in the engine.
Was having issues with an engine blowing things out a while back. Measured 120+psi in the block at about 2500rpm or so. (It had insufficient bypass area due to several factors) As a test, measured the pressure in a 3-liter pushrod Taurus. 45psi in the block.
To be honest, I have no idea how engines with suction-side thermostats even work. How do they build pressure in the cylinder head to keep the coolant from boiling around the spark plugs and exhaust ports?
Thermostats aren't perfectly sealed and don't hold pressure, some even have a hole intentionally drilled in them from the factory to prevent a perfect seal (which would also make getting the air out of the system much harder). So pressure in the coolant system should increase uniformly with temperature.
GameboyRMH said:I put 16psi caps on my cars which both originally used 13psi caps. Note that hose blowout frequency seems to increase exponentially with system pressure though, and it gets really bad above 18psi.
Simple physics. Your original system is designed to overflow at 13psi. Up the potential energy to 16, and what used to be not noticeable has enough to make it so. And it’s worse at 18.
GameboyRMH said:Knurled. said:In reply to rslifkin :
That is radiator cap pressure, not the pressure in the engine.
Was having issues with an engine blowing things out a while back. Measured 120+psi in the block at about 2500rpm or so. (It had insufficient bypass area due to several factors) As a test, measured the pressure in a 3-liter pushrod Taurus. 45psi in the block.
To be honest, I have no idea how engines with suction-side thermostats even work. How do they build pressure in the cylinder head to keep the coolant from boiling around the spark plugs and exhaust ports?
Thermostats aren't perfectly sealed and don't hold pressure, some even have a hole intentionally drilled in them from the factory to prevent a perfect seal (which would also make getting the air out of the system much harder). So pressure in the coolant system should increase uniformly with temperature.
....I just described how I measured the pressure in the block in an engine with a functioning thermostat.
If you aren't measuring, you're guessing.
Block pressure is also a good indicator on if the water pump is working at higher RPM. If the pressure starts fluctuating rapidly, the impeller is cavitating and no longer effectively pumping coolant, and needs to be slowed down.
On an engine with an output side thermostat, block pressure will be somewhat higher than the rest of the system, although the difference gets smaller as the temp gets hotter and the thermostat opens further.
Upping the cap pressure will up the pressure everywhere, including in the block. My biggest concerns with higher pressure would be things like radiators and heater cores ballooning and failing under the extra pressure. Hoses can always be replaced with stronger ones and then double clamped.
44Dwarf said:Also from an engineering side. at the elevated temp a non aqueous coolant can run with out having localized boiling in theory it should keep the temps from Rapidly running away however the parts it is cooling is still running hot. Fix that problem don't try to band-aid over it. In the 90's when hi HP litter sized bikes came around to the norm, when the coolant reached 255 it was norm for the bike to start smoking the next time it fired up due to ring loosing tension. Adding a coolant that doesn't boil over just means you don't have to stop due to boiling over but your still killing the motor... True the killing band maybe moved up some degrees but your still doing damage if your running hot. Fix the problem not mask the symptom.
I agree that going really hot isn't good, but 255 causing smoking in a few examples doesn't really mean much. When you start a cold engine at 20 below and then run it up to 210, it's perfectly fine. Another 40-50 degrees isn't going to cause horrific damage. If you think about it, flame fronts can be well over 2000 degrees, cast iron melts at 2800 degrees, and aluminum melts at 1200 degrees. Even the wimpiest paper gaskets won't burn until about 500 degrees. When you overheat an engine to the point that it seizes rings and pistons, it isn't due to the fact that you hit 250 degrees, it's because the boiling water removed the ability to cool things in that specific spot and the temps spiked. I promise that a 250 degree piston isn't seizing. A 500 degree piston, maybe.
Evans told me (not sure how much I trust them since they are hocking a product) that 300 was my "start to worry" point, but it wasn't because 300 is too hot for the engine, it was because it could start cooking the oil and/or making it too thin.
Anecdotally, I can tell you that a Lemons Honda D16 with a decent oil cooler will race for at least 4.5 hours with almost no water in it. After that, I put a piece of tape over the stock temp gauge so that anything above 1/3 was hot because guest drivers don't listen.
IDK what oil temps got to....probably hot.
freetors said:So yeah it is a different approach to cooling, but 10 year antifreeze is readily available. I think that's pretty reasonably hassle free.
And let's not forget that just because an engine can tolerate running metal temps of 250+ degree, does not mean that it should be up there! All of the modern engines I've seen have been pretty rigorously engineered to run at 200-220 degrees all the time for power, longevity, and emissions. Pushing beyond that really puts you into unknown territory.
I agree and disagree. They are engineered to run at 200-220 because they don't have a choice. If the industry norm back in the day had been to run a non-aqueous coolant, the whole concept of boiling wouldn't even be an issue and I can almost guarantee that engines would be running 250-300 degrees. Improved MPG possibility, lower CO emissions, and (provided that the amount of heat transfer remains the same) no additional NOx. Reliability is also improved at higher temperatures. Temperature is immaterial. As long as heat transfer is adequate, engines would much rather be hot. People are obsessed with thinking cooler is better, but it just isn't true. A hot engine is a happy engine.
Manufacturers engineer them to get up to 200 degrees as quickly as possible for emissions reasons, but they have to stop there because of boiling. Without the boiling problem, you don't have to stop there. It's not that 200-220 is "just right," it's just what they have to work with. They don't have a choice. As an engine builder, I would LOVE to run engines at much higher temps
Again, I'm not touting the glories of NPG coolant, I'm simply being a voice of science. Overheating damage has nothing to do with a magic 230-degree number.
Hot is good, but higher temps do present issues with lifespan of rubber and plastic parts on and around the engine, so that can be a cost concern for production engines. BMW has issues with it on some of their engines that run 220 - 225 as normal operating temp. The same basic engine in older models that run 20 - 30* colder get much better lifespan out of some of the same parts.
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