32 replies to this topic

[jack be nimble]

The smaller the drops, the more surface area is presented to the air to drop the temperature of the air before it gets to the intercooler.
The smallest drops are made with higher pressure and smaller nozzles.

I have irrigation nozzles on the patio. They are nowhere near as good as the high pressure setup that i have seen about. You dont want the intercooler (or the people) to be wet. You want all the water evaporating and cooling the air.

[leadfoot]

i would have thought even if a small amount got onto the cooler it would quickly evaporate and cool the core directly

[jack be nimble]

Dunno. The article says-


Evaporating a kilogram (ie a litre) of water requires 2257 kilo-joules of energy – and that’s a lot! If the nozzle flows 400 ml/minute, and if all the water evaporates, each minute 903 kilo-joules of energy are extracted. One joule per second is the equivalent of 1 watt, so fully evaporating 400 ml/min of water provides a cooling power of 15 kilowatts! Even a 130 ml/min spray provides a potential cooling power of just under 5kW.

The key point is that the water must evaporate – it is this change of state from water to a gas which absorbs the energy. If the water droplets do not evaporate, they basically provide almost no cooling performance. And the key to getting water to evaporate is to use very small drops – an atomised mist – which dramatically increases the surface-area-to-volume-ratio of each drop, promoting evaporation.

In addition to drop size, the rate of evaporation will also depend on the relative humidity of the air (if you like, an indicator of how much ‘room’ there is left in the air for evaporated water) and the temperature of the heat exchanger.

With a good enough spray, there is no technical reason why the temperature of the intercooler cannot be brought lower than ambient. After all, that’s how evaporative air conditioners work...

[jack be nimble]

It is a bit of a suprise there is no test results as evo-gsr mentioned. Often the autospeed team test and rate their results.

[ENGINR]

I have seen logged Motec data showing intake temps drop by 8-10deg on my mate's 2.0L turbo Ford Escort Improved Production track car when the intercooler spray has been used.

 

A spray setup alone won't result in massive power gains, but anything that takes heat out of the engine will help it run more efficiently and keep it alive a little longer, especially when you're driving it hard for up to 10minutes at a time in a track outing (I'm not talking "road warrior" crap either, where you boost around city streets "battling" other Sunday drivers, blasting through the hills with your mates or 11-12 second qtr mile runs where nothing really has the chance to heat up).

 

The trick is to get the spray working on the intercooler before it gets too hot, otherwise you won't be able to maintain your ideal core temperature and get enough heat out of the charged air to extract maximum efficiency, so you need to set the spray up on an automatic trigger that kicks in when a certain intake temp and road speed is reached. To conserve water you should run the power through a flasher setup so the pump pulses the spray instead of just staying on continuously and draining your water supply in the first 1.5 laps of your track session.

 

It makes me laugh seeing the intercooler spray buttons in factory setups - what do they think people will do? push the button expecting it to be like a NOS injection that will unlock hidden "killerwasps" from their engine?  "Hmmm.... I'm losing this drag battle, better look for and push that intercooler spray button to get the competitive edge back...... UH-OH! DANGER TO MANIFOLD!!!"

 

It would be cheaper for OEMs to ditch the intercooler spray button and just program the ECU to read the intake temp and road speed inputs (or engine rpm) and have the intercooler spray trigger automatically like I mentioned.

[Rockabilly]

Use 50/50 Metho/Water & get the IC pissed & cool at the same time.

Aldo

[ENGINR]

A pissed intercooler would send the charged air back to the turbo instead of on to the throttle body Aldo, everybody knows that!

[jack be nimble]

UH-OH! DANGER TO TURBO!!!" 

[Benzo4gT]

Be careful, a floor panel might fall off, plus if you switch it on too soon you'll lose to a Honda.

[ENGINR]

[Pretzil]

I'm not sure what the OEM spray motor setup is on these cars, but maybe you could try boosting the voltage:
http://www.autospeed...rticle&A=111490

 

This was my attempt, ran a cheap supercheap auto washer spray motor at 24volts. It easily achieved a very fine mist, heaps more pressure than at 12V. This is with cheap plastic patio misting nozzles from ebay.
 

My positioning still needs more work though, was trying too hard for stealth behind the plate and hoped spray would blow back. Instead it hits the plate and drips.

Edited by Pretzil, 01 January 2016 - 11:32 PM.

[ENGINR]

Looks good, will be interesting to see how it compares when you've refined your positioning to avoid the number plate.

[Pretzil]

Oh, and I also fitted these sensors so I'll actually know if it works.

http://www.ebay.com....lue-Digital-LED

(no, that stupid gauge isn't mounted on my dash, I just plug it in it when experimenting.

It is really interesting to watch though, the hot side temp jumps immediately on boost, the cold side barely moves and just creeps up slowly.
But once the outlet side creeps too high, that's when you need the spray.