Thread: water spray on a 300tdi intercooler

Personally i don't think it would yield noticeable benefits.

THe water doesnt do a whole lot by itself, on the Jap cars it's sprayed on at speed, so the air rushing past cools the water down considerably.

But i'm guessing we'd want to use it at low speeds, hill climbs etc..where that air flow over the water/intercooler doesn't really exist.

If you were keen, i'd look in to installing a large thermo fan on the back of the intercooler, cowl it in etc..and then switch it on when using the water spray. that'll get close to providing the airflow across the 'cooler to take advantage of the water.

Alternatively, take a leaf out of the Gibson Motorsport handbook and a plumb a CO2 fire extuingisher up to spray on the intercooler (gotta love bending the rules!)

I think you'd be surprised.

Evaporative Coolers don't run high speed fans and they are very effective at dropping the ambient temp.

Guess I'll have to have a go and do a report.

I like the idea of a switchable thermo. style fan for low speed stuff.

here's an exert from "The Bible". (free plug, buy a copy! great book for understanding anything and everything about turbo/super charging. Heaps of theory that can be applied across the board!)
[ame="http://www.amazon.com/Induction-Performance-Practical-Supercharging-Turbocharging/dp/1859606911/ref=sr_1_1?ie=UTF8&s=books&qid=1258162280&sr=8-1"]Amazon.com: Forced Induction Performance Tuning A Practical Guide to Supercharging and Turbocharging (0699414002061): A. Bell: Books[/ame]

This is obviously relating to race/road cars, but presents a few more factors to think about.

A good water spray onto the core of an air/air intercooler will increase its heat rejection efficiency upto about 8%. THat may not sound very much, but as we increase intercooler size it becomes more and more difficult to get big efficiency increases. For example, a cooler that is 70% efficient will require about 35% more core area to achieve the 8% improvement possible with a properly engineered water spray sytem. However, to be really effective a water spray arrangement has to dump a lot of water onto the entire area of the charge cooler core. THis means aa large water tank and correct positioning of nozzles. Competition cars regularly have a 30-litre water tank which is sufficient for about 30 miles on a race circuit or rally stage. This raises the question of weight - will the handicap of an additional 30kg of wieght, assuming a 30-litre water load, be offset bu the performance gain arising from increased charge density and attendant detonation protection?
Obviously water loads should be kept to a minimum. This means the spray nozzles and pump must be correctly sized to provide only the volume of water necessary for effective charge cooling. Also, the system must be activiated only when the intercooler core temperature or the intake temperature, measured at the inlet manifold, reaches a particular level - perhaps 10-15degrees celsius above our target inlet temperature. Triggering water spray with reference to boost pressure is not very effective as it does not take into account ambient temperature and the additional cooling provided by increases in car speed.
Race teams adjust water flow rates, nozzle position and spray pattern based on readings from perhaps half a dozen temperature probes placed strategically around the cooler core. An alternative is to use a big dyno blower fan and very carefully view the spray pattern. You have to keep out of the air path so you will need very good lighting and perhaps a pair of binoculars to clearly see what is going on. Water flow rates can be adjusted with the car running under load on a wheel dyno or on the track. With a temperature probe into the inlet manifold or cooler outlet, attempt to achieve low charge temperature with minimal water flow. It makes little sense to double the water flow for a temperature drop of a few degrees. It can take a lot of work and expense to take 10kg out of a race car, so always balance out water flow against the added wieght you will have to carry. For a race car a pre-race water level check should be a regular item on your check list. However, for a road car it is easy to forget, so you will need a low water level buzzer to remind you to take it easy until you refill with water. Don't rely on warning light, you may melt a set if pistons before you notice that it is on!

Obviously everything about race weight etc.. is redundant in this case, but figured i'd post the whole chapter up anyway

You could most likely use an existing EGT signal to trigger the sprayers as well, as that'll be fairly indicative of intake temps (presuming boost stays constant).

For a really simple setup, you could use an EGT signal with one of these Universal Voltage Switch - Jaycar Electronics to trigger the water sprayer and a thermo fan. Can tune those voltage switches to turn on at X degrees, and then turn off once it gets below X degrees again. (X being whatever you decide EGT is too high)

im keen for giving it go, nothing to loose, il just take off the rear washer hose and run a new one to the IC,

Have a look here
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and search for Water spray intercooler.

Autospeed has done quite a bit of research and sells an intelligent water cooler spray kit.
BUT you need a high pressure pump and fine spray nozzle.
Regards Philip A

My standard 1995 300 tdi has twin electric fans in front of the radiators as well as the viscous fan. There is absolutly no room to mount a fan behind the radiator or intercooler.

Nothing new

In the end of the eighties and early 90's the Lancia Delta Integrale as standard had jets from the washer bottle which would dump the washer bottle contents on the inter cooler at a preset timing depending on hot much stick you were giving the car.

My mate had one and was always moaning that the screen wash was always empty. But as we used to point out is was his fault to caning the car everywhere

If U wanted to go Water to Air IC then one of these Barrel Coolers would be much neater.