Coolant alternatives

[Jeff Davison]

Has anyone here had any experience with non aqueous coolant?

Specifically Propylene-Glycol

Seem to have to very positive atributes.

Like to see any first hand experience with the product

here's a link to a suppliers web site:

http://www.evanscooling.com/main31.htm



Jeff Davison

[colin artus]

I read an article in Circle Track magazine about this some years ago and as I recall one of the benefits was to allow the engine to run hotter. This might cause other heat related problems in the back of a Strat.

Colin

[rutthenut]

I'm very sceptical of most of these alternative products, even if there is some proof that they may actually work - I take the view that it's mostly 'snake oil' :eek:

Some of these things can lead to other problems, and maybe trigger water leaks (which should be easily fixed).

Essentially, I'd stick to the view of "If it ain't broke..." and I've not had cooling problems to make me look at any sort of fix like this.

[colin artus]

NAPG runs in a non pressurised system so I dont think leaks would be a problem. It does however require about 20% nore volume than water for the equivalent cooling capacity.
There is nothing that has better heat absorbtion capacity for a given volume than water so dilution with glycols (antifreeze) reduces cooling capacity. However, antifreeze is a corrosion inhibitor so some amount is necessary. I have found WaterWetter from Redline to be usefull as it acts as a corrosion inhibitor and has a marginaly beneficial effect on cooling capacity (breaks down surface tension). You will still need antifreeze in the winter though if there is any danger of your car being subjected to freezing temperatures.

Colin

[Jeff Davison]

NPG has a boiling point of 390 drg F. Whereas water in a 50/50 antifreeze mix and pressurized at best is only 250 deg F.

Water may take the heat away faster, but cannot when and where the "hot spots" in the engine cause the water to boil. The vapor barrier on the metal in those areas prevent metal to water contact, completely reducing any ability the water may have to transfer the heat away.

In hard driving, sure the engine may run hotter, but the foibles of a water based coolant will not rear it's ugly head (of steam) as there is no water to boil over, boil out or vaporize in a non aqueous system.

So in a given situation where equal engines are driven hard, one may be pulled over with an overheating system and one would still be running strong on a hotter running system.

The key distinction here is the difference between hot running and overheating.

Interanal combustion engines are very likely to be more thermodynamically effecient at those slightly elevated temperatures. The limitation being the temperature of the oil's break down point.

The only thing I would be worried about in an engine bay that would be home of an intentionally hotter running engine is supplying cool air to the intake and a good oil cooler.


Jeff davison

[colin artus]

NPG would seem most suited to race car installations using pushrod V8 engines like those in Nascar. Those two valve engines suffer particularly from hotspots in the combustion chambers due to the necessity for very large diameter ports, which leaves little room for the coolant passages. Due to restrictions on the intake capacity they also suffer from high temperatures at the exhaust valve which makes these problems worse. Running with little margin on the timing, detonation must be a real problem. The extra weight of an NPG system isnt going to matter so much in a car weighing 3450 lbs!
What I would like to know is what they use in F1 engines where every gram of weight is critical and the cooling requirements are really extreme. Could it be distilled water? Surely too low tech!

Colin

[Jeff Davison]

Good points Colin.

Even with a car weighing between 1700 and 2000 lbs, there is much of a weight penalty in the difference between a few gallons of water and a few gallons of NPG. That souldn't be an issue.

Yep those F1 cars are the state of the art and probably the most effecient engines in existance....F1 cars really have to keep in motion however. The only slow time they see is coming into and out of the pits, and even then there is quite good airflow through their radiators. They get away with pure water because of their contstant hi speed and airflow. Now put that F1 car in traffic and throw some newspapers in front of the radiator.....poof.


Jeff Davison