Replace coolant with just H2O?

[ShadeD1]

I'm having some overheating problems at the track since I reprogrammed the ECU and was considering draining the radiator and replacing it with just water, water wetter, and the minimum amount of coolant necessary to keep it from freezing. I live in Houston TX and the coldest we EVER see is about 20F.

I have a few questions:
1. Has anyone here done this and if so did it make a difference on car temperatures?

2. Do I need to use BMW anti-freeze or will any brand work.

3. Any guesses on how much coolant to use, I know as little as possible but I don't want my engine to freeze on the 4-5 sub freezing days a year we get here in the south.

Thanks

[SamS]

That's not a good idea.

Someone can correct me, but coolant is not just added to water to keep from freezing, but I think it changes the boiling point too. You don't want all your H20 to boil off.

[JAJ]

What Sam said!

Anti-freeze is also anti-boil, so you need it to keep from boiling over. BMW's recommended blend is 50:50, which according to Wikipedia, gives you a boiling point around 269F with a 15# radiator cap. That will drop somewhat, perhaps to 260F or even lower if you reduce the antifreeze to 30%. Reducing the glycol content from 50% to 30% increases the specific heat (heat carrying capacity of the fluid) by about 10% at the same time. The risk is that if that increase in specific heat isn't enough to actually solve the overtemp problem, the lower glycol mixture might boil before the ECU intervenes and cuts the power. Glycol and water blown all over the track won't make your fellow drivers happy, and could result in serious damage to your car or others.

Just get a bigger radiator and/or a bigger oil cooler. That's more likely to work the way you want it.

As for which one to use, just use the BMW coolant - it's not particularly expensive and it's compatible with the metals and plastics in the engine and cooling system.

[ShadeD1]

Thanks for the replies, I had not thought about the boiling point.

[Gearhead999s]

Engine ice will help.

http://engineice.com/

[Jaypod]

I recently just put some Engine Ice in - I see a pretty big difference in operating temps on and off the track. (I am supercharged) Havent had any issues and you wont have to worry about freezing.

[Erhan]

Originally Posted by Gearhead999s

Engine ice will help.

http://engineice.com/

Where did you buy from? Thanks.

[Jaypod]

Originally Posted by erhanh

Where did you buy from? Thanks.

He didnt buy it - just going from my experience...

I bought it from a Motorcycle shop. Here in Canada, Canadian Tire also sells it, but not all of the locations.

[tom @ eas]

Originally Posted by JAJ

What Sam said!

Anti-freeze is also anti-boil, so you need it to keep from boiling over. BMW's recommended blend is 50:50, which according to Wikipedia, gives you a boiling point around 269F with a 15# radiator cap. That will drop somewhat, perhaps to 260F or even lower if you reduce the antifreeze to 30%. Reducing the glycol content from 50% to 30% increases the specific heat (heat carrying capacity of the fluid) by about 10% at the same time. The risk is that if that increase in specific heat isn't enough to actually solve the overtemp problem, the lower glycol mixture might boil before the ECU intervenes and cuts the power. Glycol and water blown all over the track won't make your fellow drivers happy, and could result in serious damage to your car or others.

Just get a bigger radiator and/or a bigger oil cooler. That's more likely to work the way you want it.

As for which one to use, just use the BMW coolant - it's not particularly expensive and it's compatible with the metals and plastics in the engine and cooling system.

+1

Lots of track rats run 100% water with Redline Water Wetter added for maximum cooling, but its not recommended for everyday use as this removes the anti corrosion capabilities antifreeze/coolant offers.

OP: You can try adding a bottle to see if this helps in your case.

[Bubbles]

Use distilled water (not tap water) if you go that route. I used to run straight distilled water wetter in my 335i for track days (huge heat issues). I wouldn't do it to my M3.

[tom @ eas]

Originally Posted by Bubbles

Use distilled water (not tap water) if you go that route. I used to run straight distilled water wetter in my 335i for track days (huge heat issues). I wouldn't do it to my M3.

Very good point!

[rzm3]

Here's an article I found which offers a counter viewpoint...

It is true the antifreeze will increase the boiling point of the coolant, however, other properties which are critical to efficient cooling are negatively impacted, such as:

50/50 mix vs. 100% water at 1 atm
Specific heat: -19% (amount of heat a unit of fluid can hold)
Latent heat of evaporation: -31% (energy it takes to evaporate a liquid)
Thermal conductivity: -32% (how quickly heat transfers)

For these negative impacts you would get a +7% increase in boiling point (100C to 107C).

Therefore the author argues that 100% water will be far more efficient as a coolant despite having a slightly lower boiling point.

http://www.rehermorrison.com/blog/?p=228

[montreal red]

Originally Posted by rldzhao

Here's an article I found which offers a counter viewpoint...

It is true the antifreeze will increase the boiling point of the coolant, however, other properties which are critical to efficient cooling are negatively impacted, such as:

50/50 mix vs. 100% water at 1 atm
Specific heat: -19% (amount of heat a unit of fluid can hold)
Latent heat of evaporation: -31% (energy it takes to evaporate a liquid)
Thermal conductivity: -32% (how quickly heat transfers)

For these negative impacts you would get a +7% increase in boiling point (100C to 107C).

Therefore the author argues that 100% water will be far more efficient as a coolant despite having a slightly lower boiling point.

http://www.rehermorrison.com/blog/?p=228

interesting !! i always thought people who run straight H2O with no anti-freeze dont know what they are doing... i guess i may be wrong.

[mastek]

Race cars (amateur and pro) are forced to run without coolant so to prevent a spilled ice rink on the track in case of a leak.

[r53s65e90]

Originally Posted by mastek

Race cars (amateur and pro) are forced to run without coolant so to prevent a spilled ice rink on the track in case of a leak.

Same goes for motorcycle track days.

[LiM3y]

Originally Posted by mastek

Race cars (amateur and pro) are forced to run without coolant so to prevent a spilled ice rink on the track in case of a leak.

I thought ice was made from water? Or has Obama changed that too????

[JAJ]

Originally Posted by LiM3y

I thought ice was made from water? Or has Obama changed that too????

No, it was the Tea Party that changed it. Something to do with making iced tea more fun to drink.

I think Mastek actually meant that race cars run without glycol coolant additives (antifreeze). If they ran with no coolant at all, the only cars that would even make it off the grid would be air cooled Porsche's.

[LiM3y]

Originally Posted by JAJ

No, it was the Tea Party that changed it. Something to do with making iced tea more fun to drink.

I think Mastek actually meant that race cars run without glycol coolant additives (antifreeze). If they ran with no coolant at all, the only cars that would even make it off the grid would be air cooled Porsche's.

[motorking]

Originally Posted by ShadeD1

I'm having some overheating problems at the track since I reprogrammed the ECU and was considering draining the radiator and replacing it with just water, water wetter, and the minimum amount of coolant necessary to keep it from freezing. I live in Houston TX and the coldest we EVER see is about 20F.

I have a few questions:
1. Has anyone here done this and if so did it make a difference on car temperatures?

2. Do I need to use BMW anti-freeze or will any brand work.

3. Any guesses on how much coolant to use, I know as little as possible but I don't want my engine to freeze on the 4-5 sub freezing days a year we get here in the south.

Thanks

Good morning,
I am the technical manager at Prestone coolants. Using str8 water is really bad for your cooling system! Antifreeze/Coolant has more purpose than just freeze protection. The additives in AF prevent corrosion in the cooling sustem. Water is very conductive and running str8 water in your system can turn it into a giant battery and cause what is called electrolysis. Your cooling system will corrode from the inside out. You also need lubrication for your water pump seals. You can use Prestone extended life coolant in your BMW. Use a minimum of 35% coolant concentrate and distilled or deionized water along with the water wetter. Carefully clean the radiator external fins using cleaners marketed for cleaning a/c condensors. Removing dirt build up on the radiator fins can reduce cooling system temps considerably.
Jay Buckley
Prestone Coolants
jay.buckley@framgrp.com

[ShadeD1]

Wow, that was very helpful. Thanks!

Originally Posted by motorking

Good morning,
I am the technical manager at Prestone coolants. Using str8 water is really bad for your cooling system! Antifreeze/Coolant has more purpose than just freeze protection. The additives in AF prevent corrosion in the cooling sustem. Water is very conductive and running str8 water in your system can turn it into a giant battery and cause what is called electrolysis. Your cooling system will corrode from the inside out. You also need lubrication for your water pump seals. You can use Prestone extended life coolant in your BMW. Use a minimum of 35% coolant concentrate and distilled or deionized water along with the water wetter. Carefully clean the radiator external fins using cleaners marketed for cleaning a/c condensors. Removing dirt build up on the radiator fins can reduce cooling system temps considerably.
Jay Buckley
Prestone Coolants
jay.buckley@framgrp.com