Water Coolant

[rbodor3]

Everybody has heard of running 100% water coolant 'trick' during the summer, and the increase your radiator cap PSI trick also.

During warm months I switch from 50/50 to 100% water typically, but recent discussion has made me rethink this.

Water has a lower boiling point then most antifreeze's. There are (of course) specially formulated antifreeze with high boiling points and similar heat transfer (or better) as water, but are quite expensive (of course).

Water boils at about 210*F at 1 bar, most of our cars are probably running around 180-220*F depending on driving conditions/location. If you boil water in your coolant you will have issues (air, overheating). But, by increasing the pressure your boiling temperature rises, typically so does efficiency. Typical system pressure I've noticed is about 12-15psi (about 1 bar more). Boiling temp of water is ~250*F at 2 bar. Still kind of close to typical running temperature.

You could increase the stock pressure, but too much pressure = system leak.

2 part question:

1) What's the design pressure of our coolant systems?

2) What is your opinion on decreasing water temperature for the summer, and your argument?

[Oreo931]

[Young Burnsy]

If antifreeze works better across the board than water does. Why would you even consider using water? It's not like regular antifreeze is expensive. I agree with Adam.

[socal850tuner]

Running 100% water is no bueno my friend... this can cause oxidation issues within the cooling system. Anti-freeze not only helps stop this but supplies better lubrication to the water pump due to the viscosity of coolant. The goal is to have the highest boiling point possible as this is directly proportional to the heat capacity and heat absorption rate of cooling system.

[Falcone]

I'm with these two. Had a similar discussion with a subi buddy last week. I'm all for doing things differently, but this isn't something i'd even consider.

[JCviggen]

Straight water has better cooling properties. But for a daily driver I say stick to an antifreeze mix. I run demineralised water + water wetter in my T-5R. If I bust a hose on track it's a lot less slippery for everyone behind me + better cooling.

[rbodor3]

If antifreeze works better across the board than water does. Why would you even consider using water? It's not like regular antifreeze is expensive. I agree with Adam.

The antifreeze I was referring above isn't typical coolant (it's NPG), regular coolant doesn't cool as well as water.

Straight water has better cooling properties. But for a daily driver I say stick to an antifreeze mix. I run demineralised water + water wetter in my T-5R. If I bust a hose on track it's a lot less slippery for everyone behind me + better cooling.

I run the same thing right now (clean water + redline), without any previous thought. I guess the argument is more - by running water we're running pretty close to the boiling point. What *FWT do you see? Typically I run anywhere from 188-220*F depending on how long I've been sitting still.

[Jaxx]

http://www.volvospeed.com/Reviews/engine_ice.htm

fwiw...

edit: oh yeah, distilled water + water wetter I think is the best way to go.

[Keep Calm Chive On]

i think the lowest ive heard that is "safe" to run is like 35% coolant to 65% water but you have to keep an eye on the level because the water will evaporate or blah blah. ive mixed 40/60 but i havent tracked any performance or progress out of it. i wouldnt run straight water. how about water wetter stuff? IPD has it in their catalog and its even available at typical auto stores. definatly dont do straight water because one day you may have "coolant" the next you may not. plus were a pressurized sytem and thats just gunna turn your water into steam then if you got leaks you have no steam and when your all outa both your also out a motor. there was a movie where people peed into the radiator that might even be safer (plus its renuable )

[rbodor3]

for clarification, I run water wetter with pure water, which is to prevent corrosion, buildup, scale, etc. that would be due to only water mixture.

When I ran water wetter I saw about a 2*F drop in temperature. So trying to lower temperatures with it is pointless, but using it as a supplement to pure water is purposeful.

Engine ice's boiling point still isn't really high enough for me to consider it over any typical antifreeze. Peake advertises a 260*F boiling point, which is equivalent to Engine Ice. I will say at least Engine Ice is a propylene Glycol so somewhat better for the environment which is nice.

[DARKSIDE]

I was told yrs ago by someone from RedLine that 100%-Water should only be used in race cars, NOT daily drivers...and for regular applications 30%-Coolant 70%-Water should be the max water percentage used...and of-course they recommended adding a bottle of Water Wetter...

[flaco]

Running 100% water is no bueno my friend... this can cause oxidation issues within the cooling system. Anti-freeze not only helps stop this but supplies better lubrication to the water pump due to the viscosity of coolant. The goal is to have the highest boiling point possible as this is directly proportional to the heat capacity and heat absorption rate of cooling system.

Almost agree. Boiling point is not proportional to heat capacity, or heat absortion rate. In fact, regular coolant increases the boil temp, but decreases the heat capacity of the system. A tradeoff between cooling and corrosion/longevity of the engine.

Straight water has better cooling properties. But for a daily driver I say stick to an antifreeze mix. I run demineralised water + water wetter in my T-5R. If I bust a hose on track it's a lot less slippery for everyone behind me + better cooling.

This is the best. Wouldn't use it long term or during winter tho.

In my car, I run ~50/50 distilled water (from walmart, 88c a gal) and coolant.

[ozzimark]

If you're really concerned about temps, run a cooler thermostat and a bigger radiator. If it's still a problem, ditch the stock water pump and use an external with higher flow rates.

Aside from that, for a track car, Jan's comment on not being slippery for the cars behind you is spot on. Safety first :D

[dougy]

lolol

Straight water has better cooling properties. But for a daily driver I say stick to an antifreeze mix. I run demineralised water + water wetter in my T-5R. If I bust a hose on track it's a lot less slippery for everyone behind me + better cooling.

nicely said.

[loseR99]

Also living in the South, and having had experience with the S40 (which runs hotter than hell when tuned a bit), I used 50/50 and water wetter without problems in 100F. The only changes that I believe were beneficial were ditching the 90C stat for an 87C. Also bypassed the coolant loop on the intake (if applicable). Seen here.

The most noticeable case of temperature affecting performance in the South has to be heat soak on the intercooler. Lowering the IAT significantly will probably yield much better results.

- Adam