Reverse osmosis water - Any chemists out there?

[Martynf]

Here's an interesting question for any Chemists 'out there'

Where I live the tap water is very, very hard! the calcuim levels in the water are high. Now we all know the damage hard water can do to any electrical appliance in the house, you've seen the limescale. Well the same is true to any car water cooling system. There was a fair amount of scale in my old water pump, stat housing and inside some hoses.

I have a 25 gallon a day reverse osmosis water production systems here that I use on my marine tank (corals, inverts etc). It is plumbed into the mains water supply and the water that leaves the filter is 98% pure water!! ie the residual contaminants account for only 2% of the product water.

Before I can use this water in my marine tank, I have to add various trace elements to the water as the water is too clinically clean for the animals, its been stripped of all the useful elements.

So here is the question:

Does anyone have any opions on using reverse osmosis water in a cars cooling system?

A cars water cooling system serves surely only one purpose? to carry engine generated heat away to the rads and to be cooled then returned back to the engine lower in temperature. The limescale in tap water damages the water cooling system over time, so surely 'pure' water is a good thing?

Yes? or No? anyone.....??

I don't expect the Audi coolant to react badly with 'pure' water, so is this idea a yes or no?

Martyn

[Martynf]

P.S here what I use the water on:

[S2central.net]

Nice one - I would think the purest cleanest water is what any cooling system would like. The only desireable added chemicals should come from the coolant/antifreeze (which are also designed to reduce the effects of limescale etc from tap water) so I'd give this one a green light.

You could sell this 'reverse engineered water' on VAGparts.com at a tasty profit no problem

If there's enough gullable folk in the world to buy dubious products such as 'water wetter' then you have a stout business case. Me - I'll just have a case of stout

Paul

[Pisobiker]

Martyn,


best product for cooling engine is "distilled water", which means pure H2O. This is because of high heat absorbtion (dunno english technical term) of water compared to other fluids. Any other element contained in water, such as Mg++ or Ca++ (Magnesium and Calcium ions) do nothing else than creating long term deposits that have two main disadvantages:
1- they can plug small passages;
2- Calcium and Magnesium deposits have very small heat absorbtion (almost thermally insulating) so that metal surfaces will exchange less heat with the H2O molecules, whic means less efficiency of cooling system.

Pure H2O has also better heat exchange than "GLICOLE" (dunno if this is only italian tech. term for "antifreeze" additive). Which means that any amount of glicole in the cooling system will lower its total efficiency. Only reason to use it is to lower "freezing point" of water, so that mixture should be chosen lean enaugh to have just right antifreeze protection related to geographical area (minimum temps your Country can reach).


Marco

[blu_s2]

Martyn, is that your tank in the photo? Mushrooms and Xenia's look good is it is.

I've just shut down my reef tank Decided new baby would not give me the time to keep it running as I would wish, miss the tank.

RO is just about as clean a water you will get so would seem sensible in a car, never thought about it before.

Just don't add the Reef Crystals.

[Martynf]

Paul, don't knock that water wetter stuff... a friend of mine used it in his 91 V8 and it dropped the avg water temp by 15C !! it also dropped the S2 by 10C, any reduction is temps. under an S2 bay has got to be a good thing!! The way it works is very simple, and it did work!

I don't normally go for anything like this or additives, but, that stuff worked!!

So , it sounds like a go for the RO water then? Marco, thank you for the technical info, Glycol is the English word I think if thats the correct way to spell it? Good point on the deposits insulating the heat dissapation! and you touched on another good question....

The amount of coolant required for our country? I would imagine most of the water in my system has gone now, so does anyone know how much the system holds? the correct ratio for our country (for coolant) is 40% coolant 60% water, so anyone..... how much coolant to use? I don't have a antifreeze concentration tester. I would guess 1 1/2 litres? anyone????

Yup, thats my 'fish tank' its just over 750 litres in total!! only 12 fish in it, it's purely a reef tank, the fish are only there for some colour and movement. The soft corals have grown wildy!! there isn't a single piece of rock surface that isn't covered with mushrooms, xenia or soft finger corals! It been running for 6 years now, with NO filters at all!! just 2x 10,000 K burners and two massive protein skimmers. No water changes nothing! it's grown wild!! I had to reinforce the floor of our house to take the weight of the tank! it weighs just under two tonnes!!!

Anyhow, that's way off topic

Capacity of the ABY cooling system anyone?

Thank you
Martyn

[cq20v]

Most water softeners use ion exchange columns to remove Calcium and Magnesium ions (from the carbonates - white deposits) to Sodium which remains soluble and hence less scale. Not too familiar with reverse osmosis systems but osmosis is the process of fine "filters" that let some products through whilst removing the rest (like your kindeys).

Most articles I've read recommend distilled water for batteries, cooling systems, etc.. with the appropriate amount of antifreeze.

Haynes says the capacity is 8 litres for the 5 cylinder coupe's but not sure if this includes those with aux rads too.

[S2central.net]

Reduced water temperature is not necessarily a good thing... within limits of course.

Most Audi's are designed to run with water temp at around 90 degrees C. The ECUs are also mapped with that in mind.

An S2 running at 80C water temp runs at less aggressive settings than it would at 90C as the ECU would be thinking the engine is still not fully warm. Similarly at 110C or more, there is risk of engine damage if the ECU didn't ease back settings like boost and timing.

If you run at 80C, then you will simply waste fuel and have non optimal advance settings.

All of which is why I think that water wetter is pants basically, as its supposed benefit cannot be gleamed from a stock ECU. If you are running on a track with consistently very high water temps, THEN the use of water wetter could make some sense - but not for road use - where it's a bit like driving with the thermostat stuck partially open.

Just my opinion like....

Paul

[Pisobiker]

Originally posted by S2central.net
Reduced water temperature is not necessarily a good thing... within limits of course.

Most Audi's are designed to run with water temp at around 90 degrees C. The ECUs are also mapped with that in mind.

An S2 running at 80C water temp runs at less aggressive settings than it would at 90C as the ECU would be thinking the engine is still not fully warm. Similarly at 110C or more, there is risk of engine damage if the ECU didn't ease back settings like boost and timing.
....

Well, keeping engine not running in cold conditions is what thermostatic valve is supposed to do. If you have better cooling system efficiency, valve will just stay closed (or partially colsed) longer, providing temps don't go below the 90°C setted value. When, at 90°C valve fully opens, if your system is perfectly clean and H2O to Glycol ratio is reasonably lean, the extra heat your system will be able to dissipate will better prevent temps to raise over limits at which ECU starts reducing overall performances.
And this, in my experience, with engine power upgrades and external temps climbing over 35-38°C does happen pretty soon !!

Marco

[Martynf]

Thanks Paul and Marco!

Didn't mean to open a can of worms!!! Never thought about the ECU side of water temp related operation! good point!!

Oh well, another good idea bites the dust!

8 litres for a 5 cyl, thanks Owen! there probably is some residual water still in the block, so maybe I'll run the system up in the garage on just water and check for any leaks, see how much it needed, then drain it and refill with RO and the right % of coolant.

Thanks for the input guys, don't you love the combined knowledge of everyone here :-)

Cheers
Martyn