04STI UK
I have the button on the dash and ....great, does it make much difference??
I drove my cousins Evo8 FQ300 its automatic, it seamed to come on at max boost although not always possible to study intently at those times!!
The question is that if this is when you use the spray then I presume that Subaru are intending us to be flat out on full boost whilst removing your hand to press a fiddly button in each gear whilst going sideways etc......??
When I picked the car up from the dealer they were on about how cars go better in foggy / misty days so thats what it was for?? - presumably its simply to help cool the intercooler and hence the air etc.??
I also assume that its just standard water in the container? - has it a low warning light?

It it just a gimmick? or if nec why not auto like the evo8??
when do you use it?
cheers Paul.

 

Personally, I wouldnt call it a gimmick - it seems to do a good job on my type-ra. On a foggy day there is a lot of moisture in the air, which has quite a significant cooling effect (so more power). What the waterspray tries to do is mimick these conditions in a crude way.

Only annoying thing is that I end up filling it up every couple of days!

 

I used to use mines a lot (04 sti), mostly when out a blast, i used it as more of a precaution more than anything else, hot temps & meltdown springs to mind
I cant honestly think why the didnt make it auto would have made more sense

And yes there is a low level light, got the fright of my life one when day when out for a blast & out the corner of my eye seen this yellow light come on & then off again, so i reverted back to normal pace, few days later doing the same & it came on again but with an I/C in yellow, felt a lot better i can tell you & yip just normal water, though my ex used to have a go as i would go into the petrol station & appear with a bottle of mineral water to fill it up

Enjoy the fun

 

The lack of an auto on UK cars seems madness to me. Just when you most need it, you want both hands on the wheel and your eye on the road - it's hard to hit without looking!

As for filling up every 2 days... I fill mine about every 20k miles!

 

You can use straight water but I put a mixture of screenwash/water - Im sure I read somewhere that it makes the intercooler even colder than straight water- it also stops the tank freezing in this weather!

THe button on the classic sti is fairly big and accessible so I dnt have any trouble activating it while driving - reading the boost guage is a different matter though!

I think it is supposed to be auto activated on my car but have never noticed it kick in - I wonder what solenoid is used to activate it

 

May be wrong... but I'm sure the MY05 Sti has both manual and auto.

Paul

 

Maybe the system worked just fine on the typeR, but take it out for a 2 hour run on auto and the reservoir will be empty. I didnt think much of it IMHO and only used it a few times.

 

Thought i read on here some time ago, they were all automatic, based on the bottle emptying without pressing the button.
RTFM ?

 

Thanks for info - still not sure what the benifits really are - dealer / tuner out there that knows?

 

It boosts your intercooler performance !

The compressor side of the turbocharger "does work" on the charge air, compressing it so that more of it can be forced into the combustion chambers. More air = more oxygen, therefore you can inject more fuel and get a bigger bang. That's how forced induction engines work.

When the compressor does work on the air to compress it, a side effect is that the air increases in temperature. Hot air has more energy and a fixed mass of gas will occupy a greater volume at a given temperature than colder air. Put another way, cold air is more dense (more mass per volume) and therefore contains more oxygen.

The intercooler removes heat energy from the charge air via the intercooler matrix, the cooling side being the ambient air coming in through your bonnet scoop.

Water has a much higher specific thermal capacity than air, so injecting water spray into the cooling side of the intercooler airflow increases it's efficiency. It also directly cools the intercooler heating matrix too.


You will notice the biggest difference on hot days.

HTH,
BIJ

 

No, the UK spec car is manual only, JDM comes with auto and manual options.

The auto function will empty the bottle on an STi5 in 13 miles when nailing it, just enough to last one lap at the nurburgring, funny that.

The best use of the manual switch is to help combat heat soak when sat at the traffic lights, give the button a dab just before you set off and it will spray for the first 5 seconds, apart from that manual mode is useless.

 

I beg to differ John ........ The Euro cars are automatic too and therefore i pressume the type UK's also. I get a few more laps before mine runs empty, must be a bigger tank i pressume, or higher flow i guess.

Gary

 

Gary, they arnt, its all been covered in detail in the past. You do lose some water from the Euro spec cars, but thats due to capilary action under hard braking and accelerating giving a dribble out of the jets, its not doing anything useful and is not driven by the ECU controlled pump as the JDM spec car is when switched into auto mode. The tank size is small on everything except the Spec C, which has a 20L tank in the boot.

 

I always believed that it's there because Subaru want to use it on the rally cars. They can't fit it on a rally car unless it's fitted to the road cars, it's called homologation.

But the rules allow them to change the method of actuation. So the rally cars get all singing all dancing ECU control based on boost pressure, intercooler inlet and outlet temp, throttle position etc etc. The road cars get the cheapest possible actuation they can get away with to satisfy the rules, ie manual.

With only manual actuation the best performance use of the spray is to use it every 10 secs until the tank is empty. The perfomance benefit of the weight saving from an empty tank will be more than anything you get from managing to find and press the button about 10 secs after you needed it.

Rally car - performance benefit
Road car manual - useless
Road car auto - not sure, depends what it's controlled on

Unless there is a manual / auto button next to the manual spray button then it's manual only, that applies to all UK cars I've seen. If the tank empties itself after a year that's not evidence that there's an auto mode it means you knock the button with your knee getting in and out or it's just evaporated!

 

Mine must have a leak then because I have both filled and emptied it at the ring

 

you must had a leak then mate ... mines manual

I do need to fill it up (even when I do not use it) in the summer....must be evaporation or summot..

 

Trust me Gary, its manual only on EU spec.

Chelspeed, the Spec C is the car homologated for GroupN, it has an auto IC spray system and a large 20L tank in the boot to carry enough water for the stages, as required for homologation for the PWRC cars. The WRC cars can do pretty much what they want to in that area.

 

None of the Uk Sti systems I have stripped had a non-return valve by the nozzle, yet the JDMs do - seems to be taking penny pinching to the limit.
A sort of "pseudo" auto spray system controlled by shifting weight forward.

 

my uk car has an official subaru auto switch
martin