Radiator upgrade ideas / intercooler sprayer / etc

[xsspeed]

If radiator temp gets up around 100, the water you spray on the radiator will vapourise to steam -

Yep that's the ideal scenario I think? The heat energy used to turn the water into steam is removed from the radiator/hot air, and then passed out the back as a gas rather than droplets etc.

*thinking aloud* I am not sure how much effective evaporative cooling is at ~100 degrees, I guess it like any evaporative cooling it depends on the temp of the spray water and how much energy it absorbs as it increases temp then changes state from liquid to vapour, it just seems (in my head at least) if you are spraying a mist that will be turned to steam with little effort.

The colder the water is to start with, the more heat energy is sapped from the radiator etc when it turns into steam?

Evaporative cooling generally works where a fluid say within a conductive tube is hot, and this tube is in an air stream. This is then sprayed with water, so there is a 'layer' of water over the tube. The water then absorbs some of the heat from the fluid within the tube (tube conducts heat to the water), and then it evaporates. The phase change from water to vapour also extracts heat energy from the hot fluid, as well as the other modes of cooling (radiation, conduction, convection) that are taking place.

My question is, if the water you are spraying on doesn't "get the chance" to form a film over the tube and immediately turns to steam, are you getting the same effective heat extraction? There's got to be some energy absorbed because you are changing the state from liquid to vapour, but I am not sure how much you will achieve with misting - as it would (in my mind at least) almost instantaneously turn to vapour.

^This is all just from mulling around in my head, We use evaporative cooling a bit for building HVAC in some applications, but its generally ~40-60 degrees ish, so not immediately turning to steam.

Although any form of spraying water on to an 80s Toyota is probably asking for rust problems

lol, a very good point

I guess the other issue is, what happens when you are on track and run out of water? - I guess based on the above you see the temp rise then button off for 1/2 a lap?

[Roman]

Yeah when temp creeps up, button off for half a lap or so then it's good to go again.

That's why I'm looking for alternatives to another radiator... this one is only JUST on the verge of coming to its limit with continuous thrashing, will never be an issue with lack of cooling on the street.

It wouldnt need to be constantly spraying, I could put it on an in cabin switch or use a radiator fan switch which engages at a higher temperature than the fan switch perhaps.

Refilling a bottle in between runs on the track is no inconvenience at all, it would only need enough for 10-15-20 mins absolute max. If I only turned it on when it started to get hot, it wouldnt need to work for very long at all.

It could just be completely turned off while not at trackdays, as not necessary.

[xsspeed]

At the very least it would be a pretty sweet/interesting project. Wonder what the costs would be, you could probably DIY it, finding a suitable pump and sprayers would be the hardest part (ie if not buying a FMIC sprayer kit)

[flyingbrick]

check out this link and the links linked to from this article

seems like a pretty cheap fix.

http://autospeed.com.au/cms/A_1840/article.html

[Spencer]

What coolant are you running? a 50/50 coolant mix? going to straight water with a corrosion inhibitor could be a plan, you will loose some boiling protection though. Unless you already do then ignore me