As above

Heard these top mounts are good for 400bhp
Would I need a spray on my intercooler(sti)

I dont track the car but sometimes drive it hard
cheers

Does it really need it - No

Would it do any harm - No

Is the spray a bit of a gimmick? Or does it make some difference? As I never use mine on my STI. Would I get any benefits from using it when driving hard? How do you know what to use it?

Its does make a small difference just keeps your temps down so you'd use it on boost! Sure that most have a programe so the spary knows when to go!

Mine isnt auto

I'm sure theres something you can do with it to make it auto?!? sure someone will come and correct me

All it does it cools your turbo so you can make it work harder

Mines not auto, my06 .I think that the button is in a stupid position if your driving hard the last thing you want to do is look down and try and press a button

doesnt cool the turbo at all. sprays over the intercooler. I have a temp sensor fitted in my intercooler and the spray makes little or no difference to be honest. whether it be manually when in traffic or auto when i hit the boost theres no real difference in temp with or with out it

pointless gimmick that only helps heat soak in traffic imo

Wouldn,t bother with it, lol, just get a FMIC and be done..

We all know the cooler is in the wrong place..

front mount equals lag!
its in the perfect place for instant responce pluss it doesnt get hot enough in the uk to matter!

Do engines run that much cooler in the UK then?

No you don't, as others have said it won't make any difference. You could however reduce charge temp a little by replacing the WRX bonnet scoop with an STI scoop. You'll need the undertray for it too, and make sure it has air flow baffles to spread the incoming air over the whole IC, or just the back will get cool air. Do not block the vent on the offside as it's there to blow air over the turbo.

You also do not need a FMIC unless you're running north of 380bhp.

So many opinions from people that have no charge temp gauge...

When you sit in traffic the inlet manifold temp climbs easily to 50degC due to heat soak. Pick up a little speed and it rapidly drops back into the 20's. Gun it through the gears and the temp climbs back up to 50 within a minute or two, due to the IC's inability to cope with full air-flow. This is for a standardish STi6 RA Lim (3" system, Apexi PFC, 1.4bar boost). Doesn't matter what power you're running, charge temperatures are completely out of control with a classic topmount when hanging around in traffic (or waiting for a sprint or drag run) or under continuous hard use.

Oh, and the water spray makes **** all difference.

the end was the BEST responce i have seen,,,,,, and soo true

spray hot water onto a pan being heated and see what happens,,, does the pan get cooler or does the water evaporate

BUT.... water fire extinguisher will cool the I/C,,,,, though will need some space in the boot

I asked Paul at Zen about this very thing only a week ago.
He said that the water spray, whilst being a bit awkward to use, makes a noticeable difference when the car has been subject to heat soak. He has seen power levels vary on the dyno according to charge temps and spray usage.
He wasn't saying he maps cars using the water spray, merely that it was not a gimmick and had a valid effect on the inlet temperature.

Personally I think it's bloody awkward to use, just when you're giving it the beans and need to have both hands on the wheel, you have to reach down for a button to increase the engines output by not enough to make the risk worth while.

Are you REALLY sure of your answers??

Ask Harvey about the tests he did here in the UK about temps with a top mount on..

makes what sort of difference ???

id love to know this when ragging the car,, surely water injection is FAR safer a option ???

You would on a Classic, or a New-age top mount...

how much do temps differ winter/summer?

You would have to speak to Paul personally to get the full details, but generally speaking a cooler inlet charge=higher density=greater cylinder fill, how big a difference I have no way of measuring.

Quite a few people on SN have voiced an opinion at various times that Subaru designed and evolved these cars and therefore obviously know what they're doing. Then you take something subtle like the I/C water spray, and because you don't get a kick in the back it's automatically rubbished as a gimmicky waste of time by some.
Admitedly they don't have everything right, and this system could be improved by retaining the auto function as per the JDM cars, but the principle is based on sound physics.

if the ic spray dosnt work why would subaru fit it from standard on sum models . people forget that millions of pounds goes in to developing any road car even the early scoobys so why fit sumthing that dosnt work straight out the factory

I believe the unit is more popular in hotter countries such as OZ.
To be able to spray cold water onto a hot intercooler must give for safer running,never mind about performance gains. I don't have a heat sensor but the palm of my hand tells me how hot the I/C can get, even parking for half an hour after being stuck in traffic on a hot day and its hot to touch.
I would have thought when the car is running big power levels then everything helps and to describe it as gimicky is just tosh.

Waterspray is useful to combat heatsoak, particularly useful for drag racing.

STi intercoolers are very capable units and is the unit of choice for the Litchfield type 25 running 415bhp Type25

Only because they wanted to retain the standard look. There are better aftermarket alternatives.

I/c sprays do make a little difference on some cars. The ones on the sti must make some difference but would say there more meant for hotter climates.

My mates evo6 i/c spray dose f@ck all same as the one i fitted to my saxo so thats why i went for water injection that only comes on above 25 degc but thats only on v hot days or when in traffic..

Alot. My charge temp at cruise. (not on boost) is around two degrees below ambient. It varies a little and when its really cold can get to around 5 below ambient.

They do heat up very quickly when in traffic though

Sorry - but that's impossible. The IC is a simple heat exchanger and in theory can only lose heat down to the same level as the cooling (or outside ambient) temp.

It must mean that the ambient temperature being measured is not the outside air temperature but something in the engine bay getting a little extra heat - or the charge temp readout is under-reading.
Is this "ambient" temperature the inlet temp reported by a PSI3 unit or from logging by any chance? I've found that the temp sensor with the MAF reads 5 deg too high.

My hawkeye TMIC runs charge temps at +2 deg c above ambient off boost and no better than +12 deg c on boost.

As to the OPs question - the spray is useless in the UK on a newage car, unless doing drags.
In really bad traffic in hot weather, I've even seen the charge temp rise by just under 1 degree for a split second when pushing the button. The temperature in the spray hose under the bonnet must be 50 deg +.

Nick

Got to disagree with this, I run a top mount. We are running over 400bhp and have found that the cooler is colder than the general air temp even after a flat out track session with anti lag running (no cooldown lap just straight in to take temp readings). Not a std one though. Depends on the cooler and it's efficiency, air at speed is cooler than static (wind chill) so the cooler could be colder. Standing though most get heat soak, but depends on the intercooler as to how much and how long it takes to cool again when you start moving.

A intercooler can't reduce the charge temperature to lower than the air temperature that its moving through.
If the "ambient" temp measurement is higher than the air temp blowing over the IC then a heat input is influencing the sensor reading.