Let the tinkering begin...

[Transporter]

No such thing in my world, there's ALWAYS another 0.01% to be had.

Today on a trip down the Gold Coast and back, same deal, the output of the cooler is in the high 30's on a 30 degree day, and spikes up to 100C pre cooler have no effect. Obviously there is great airflow at 100kph plus.

I'd test longer, but I've a whistle, so despite my best efforts and some silastic, I've got a leak. It's still showing normal boost pressure though, so it can't be much. I'll mount the temp probes properly in my forthcoming upgraded pipework.

I'm convinced a water spray at heat soak times, especially idling for longer than a minute, and a fan to draw the mist in at the same time is the way to go. Good news as a water intercooler setup was going to be a major mod, and there's just no need for street driving in the MKV from these results.

Might be different on the twin boosted TSI.....

At the racetrack you can fill up with icy cold water but in the normal driving conditions you water in the bottle will be at the ambient temperature and will have minimum impact when used for cooling your intercooler. You can wind the hose from the bottle around air con pipe to cool the water for intercooler down or use peltier device from small car fridges to make it more worthwhile.
Just my 2c.

[POLARBEAR666]

At the racetrack you can fill up with icy cold water but in the normal driving conditions you water in the bottle will be at the ambient temperature and will have minimum impact when used for cooling your intercooler. You can wind the hose from the bottle around air con pipe to cool the water for intercooler down or use peltier device from small car fridges to make it more worthwhile.
Just my 2c.

ACTUALLY, physics called and said that your opinion got REJECTED! heheh

"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..."

So in summary, the water temperature hardly matters as it will still evaporate when faced with a large amount of incoming air (even hot air and even if the water is hot itself). There will almost always be some evaporation unless you have very high humidity.

[Transporter]

ACTUALLY, physics called and said that your opinion got REJECTED! heheh

"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..."

So in summary, the water temperature hardly matters as it will still evaporate when faced with a large amount of incoming air (even hot air and even if the water is hot itself). There will almost always be some evaporation unless you have very high humidity.

I never said that water wouldn't cool the intercooler.
And for normal driving there is minimum benefit.
I know my physics too mate, no need to lecture me with the last minute goggled stuff what's the point? heheh.

[Greg Roles]

You two argue in someone else's thread! Polar, just do what you know works, it's what I'm doing. I've decided to leave the temp probes in there so I can see what a spray will do for it, but I'll try and plug the small air leak over the weekend.

I'm afraid I'm 100% in agreeance with my weight weenie friend.

[mollins]

always wanted to do a waterspray.. maybe when the mk1 is finished!..

btw, i drove a mk5 TDI last night.. first time in a mk5..







i want one....


keep up the great work cogdoc

[gregozedobe]

I always say good empirical evidence takes precedence over theory every time.

Take a decent set of base line measurements, make the change (eg install a mist spayer on the intercooler), then measure again and compare results (eg temperatures and power/acceleration after heat soak).

That way you know with certainty whether something is worth doing or not, and can enlighten us all (with a bonus of deadly ammunition to sort out any pesky keyboard warriors )

[Mischa]

watching and waiting thanks for doing all the research and hard work greg. modded gt tdi's ftw.

[POLARBEAR666]

On my subaru I would watch the intake air temps and the timing on my LINK ECU hand controller. It always started to chop timing when the water ran out and the IA temp went up.

I used to just have a switch to run the water constantly whenever I was fanging it and with a 12L aluminium tank in the boot it went for quite a while.

[Greg Roles]

I think my timing is safe

[POLARBEAR666]

HAHAHAH yeah... PING IS POWER DIESEL!
I keep forgetting your driving a diesel hilux with a mk5 bodykit.

You should buy a scangauge 2 so that you can monitor all the ECU outputs. You would already be able to monitor intercooler efficiency if you had one without your probe setup hehe.

Plus it clears engine codes, reads them, has 4 readouts on screen and you can choose from any the ECU outputs justabout.
Has hundreds of colour choices for the LCD backlight. etc etc etc etc.
Plug and play just whack the cord into the OBD2 port and your away!

I just cant plug this device enough. With the setting on GTI blue it matches your dash lights perfectly too!

Heres one showing 5.8L from a freeway trip. Diesel that.