Jump to content
Please check your junk folder for registration emails ×
  • Current Donation Goals

    • Raised $0.00

Anyone interested in intercooler water spray circuit, wiring and tanks?


Recommended Posts

Ok so this is now the dumping ground for ideas related to water spray for intercoolers.


Looking at adding one to mine and have a few methods.


  • One wire aftermarket ecu controlled or manual switch. Cycles through zones and fixed rate.
  • mutli wire ecu controlled pumps and zones rates controlled
  • same as Sti factory off, manual, auto option. Basically same as first but wire for external button


Design that anyone can make bolt in and wire up from cheap parts



Has a few options for sprayer as well from constant full coverage to multi zone spray mist

multizone is so more evaporation time between the spray or each area 


Same with pumps, I have found some fancy pulsed type and also ann option to use windscreen washer type or high pressure irrigation pumps.

Edited by Gripless
Link to comment
Share on other sites

Ordered parts from aliexpress.

Basic first setup will be single or dual mist spray nozzle on same line with PWM for pump 1-10Hz. Single ECU wire.


Have parts for alternating between spray nozzles if needed but that requires small circuit or second ecu wire.



Metal irrigation mist nozzle are cheap and range of sizes. Have a few hole sizes coming to match pumps with. Once matched then only need the best sized ones. A set of 5 with fittings is about $15 and you only need 3-4 for big front mount. Top mount should be 1-2 only.



The pump is apparently noisy as high pressure so likely going to have to be rubber mount under the car. Pumps come in filter or in filtered and being under car makes changing pump and filter easy as you just let it leak everywhere. Pumps also self prime if under 2m head and tank is higher so maybe 0.5m head total when under car mounted. Cost likely $15-30 depending on model and if filtered. Could use the cheap plastic fuel filter that cost a few dollars from repco etc and get cheaper pump to save money. Also then you just throw filter away and don’t have to worry about damaging while cleaning etc.


5L tanks seem easy to get, but even an old oil container would work.

Boat tanks come in 5-24L have a shutoff valve in the fuel line clip and you can remove to fill them.


Idea about making custom tanks for cheap.

Some people like things tidy or stealth so…

Just using 80mm drain pipe and capping it. Main section maybe off-cut scrap. Say the 80-100mm yellow or orange stuff in nearly 2m lengths in skip bins from buried cable yesterday.
Would fit under boot floor along width of the rear. Should still allow access to spare and tools etc.

Ends where fitting (to pump and filler) are would sit over the rear quarter drains just like the factory v11 setup. Only exposed bit would be filler and that could be a flexible neck so tucked away and pulled out past rear or car to fill so no spills.
Needs a small breather line or plate near filler to stop air getting trapped depending on final shape.

Edited by Gripless
  • Like 1
Link to comment
Share on other sites

@Andy_Mac suggested behind the bumper outside the metal car body is empty. There are loads of mount points there too. Also that it may need some surge protection.


Baffles are easy just round discs with larger bottoms hole for water and small top hole for air put on a rod before capping the pipe. Could be fancy and use fuel cell foam but that adds way more cost.


Can just use the little headlight washer caps to cover the cutout in the bumper for the filler cap to look factory. Easy to get from wreckers and already factory matched paint.

Edited by Gripless
Link to comment
Share on other sites

More findings

100mm pipe has best range of reducers for filler end eg 100-40mm which can then have flexible hose and cap fitted.


Both 80mm and 100mm come in black for downpipes from gutters so easy to get.

Sedans could have this mounted under parcel tray so very hidden and also unlikely to get hit from loose objects sliding around. Also make filler neck easy to pull out to side of car for filling.


Could T or + multiple sections of pipe in middle or ends to have stacked tanks of different sizes and make up 30L. More for multi-use street track cars. Could run dozens of laps with spray constantly on in cyclic pattern so always super cold intake. 

Fill level

Section between stack can be clear so can see fill level and run 5L for road use.

Internal sight gauge. Have second thin clear pipe through all T and + joins top to bottom with little ball so can spot easy. Pipe keeps ball from floating into tank or out filler.

external sight gauge. Small external clear hose between two L fitttings with ball inside.


NZ prices are high, parts here $15-35 or $3-10 in AU both inc GST. So need to find so cheaper places or scrap pipe jointers etc.




Edited by Gripless
  • Like 1
Link to comment
Share on other sites

Yet more
If needs to run on regular full time pump can use a 3 port valve to have default to return water to tank. This would make sure not dead headed and reduce stress on pump. Then interval timer to switch on. Can be as simple as a timer relay 2s-2min adjustable running 3 port.

For easy adjustable standalone option, unsolder the trim pot resistor in relay and attach larger trim pot and knob near centre console. Could use dial like headlight dimmer and clip into dash etc.

Link to comment
Share on other sites

  • Gripless changed the title to Anyone interested in intercooler water spray circuit, wiring and tanks?

Hydroponics pipe look good.

Thick walls and rated to hold water weight when horizontal. Flat surfaces so can drill and mount filler anywhere if you don’t get 20mm outlet end cap.

Per meter 5L or 10L which should fit behind bumper.


pipes 100x50mm or 100x100mm

end caps blank or 20mm 


buy caps from China and pipe locally due to shipping.

Edited by Gripless
Link to comment
Share on other sites

Might be just easier in pressure pvc, as plenty of reducers and male/female threaded parts available, most merchants will sell per metre. Alot cheaper if you know a plumber 😂. Schedule 80 pvc is another option but dearer but can be drilled and taped due to the thickness of the wall. Cpc,abs hdpe are all readily available.

  • Thanks 1
Link to comment
Share on other sites

Evos all had OEM sprayers so I never had my own, but rigged up plenty of washer pumps to garden 4mm plastic irrigation misters on gtir, vr4 and random Nissans.

Evo is same as Sti near handbrake so you tap the button before downshift and passing.


Don’t have a full list yet, but it’s just simple parts..

pumps anything high pressure 70-140psi are common and around $30

AEM water Meth just uses a diaphragm irrigation pump and similar nozzles as below.



For stand-alone just need something like the OEM one  https://www.hella.co.nz/en/products/relays-flashers/time-control-relays/ there are adjustable versions from 0.2s upwards and you can put them in series to make patterns.

Nozzles are just 6mm mist in a few sizes like https://www.aliexpress.com/item/1005004136903055.html

can mount them in 6mm hole in the factory plastic under bonnet to intercooler duct.

plus they claim the line as designed for high pressure. Likely run the hard black irrigation 6mm line for everything except the short bit between body and hood where more flexible clear line would be better.


3 port for nozzle select or turn to tank on normal full time pump https://www.aliexpress.com/item/1005005197895762.html


Tanks turned out to be the expensive part.


Have to pull boot apart and measure up size in there.

Luckily my bumper is all chopped up so can just see the mounts so can measure all that tomorrow.


Edited by Gripless
  • Thanks 1
Link to comment
Share on other sites

Measured boot and there is F all space in there.

The spare tire limits middle to almost nothing.

Chassis rails limit height to 60mm 

Biggest areas 60x150x330mm on each side.


behind bumper is around 150x100x900mm 100mm is due to some bolts and the body seams higher up.


so rear bumper tank could be workable.

Link to comment
Share on other sites

One pump while makes ok pressure the pulsing can cause cavitation and if air builds up on spray side of pump it won’t pull in more from tank side. So that one is useless if the line if fatter than 2mm ID as then bubbles can collect at bends unless pump is lowest point.

Link to comment
Share on other sites

For those with canbus aftermarket ecu 



and any canbus module




esp32 has canbus controller built in so only need the transceiver that does the physical connection. Arduino needs a controller like mcp2515 plus transceiver.


Could be programmed for different operations modes.

ecu sends time to run in seconds

unit automatically runs cycles until time is up


ecu sends on

unit runs single cycle

Ecu sends start and stop

unit runs until stop received


ecu send target intake temp

unkt runs, then waits 3 second, requests temp, repeats until temp under target or stops after 10 cycles

Ecu sends status request

unit send running, idle, even water low if senor hooked up. Could be flow meter inline rather than water sensor in tank. If last run had no flow assume water low/empty.


Diag options if unit is idle ecu can request

relay # on for X seconds

relay # cycle on of at x hz for x seconds

Relay # current state. Use with above or should be off

Water level low sensor current state 

Water flow meter current reading. Need to turn on or cycle relay for pump using above.

CPU usage

Memory usage

CPU temp

Board temp

Even Wifi status if those are used. could run wifi AP with webpage showing connections and status of each part of unit and connected pump.




canbus dumb version have to trigger each relay.

More suited to meth or extra pump control etc.




Alternative dumb single wire for button. You trigger input1 that runs 10 seconds triggers input2 input3 which run pump and solenoids in pattern as required.

single press with can run a single cycle.

input4 could run different or longer pattern. Or turn in intercooler fan when handbrake is on.


Edited by Gripless
  • Like 1
Link to comment
Share on other sites

Have worked out canbus code byte values.


Only thing it needs to have hard coded is ID and the ID to listen for the intake air temp for auto mode.

Auto to intake temp needs high and low byte as second byte would be target temp.


Relay cycling has to be preset number or needs high and low bytes so can set default to 10. Since the idea is just to get it to click so you can tell if relay is dead.


4 relays can do

Any 1 of 4 zones but spray is on/off by pump

advatange is more zones,

disadvantage spray comes on slow as pump builds pressure at start and drops at end so wastes a small amount of water each time. No delay between zone spray, just one after the other.


Any 1 of 3 zones and pulsed by solenoid that return water to tank or before pump until need.
disadvantage less zones. Pump still runs full time.

advantage build up and cut off are instant from solenoid so zero drip waste. Can program in more delay between zones so has longer evaporation time. More cooling less water.



esp32 can have wifi updates to code so could be DIY setup even on car without access to usb or serial connector.


Could preset the canbus ID to a default ID in a known range based on ecu like link, Emtron motec etc.

  • Like 1
Link to comment
Share on other sites

Needs more work, but initial syntax in single byte messages



  • Startup code to announce IC spray unit is working and ready
  • A way to return zone count
  • Some operational error for water level and flow rate returned values (eg count over what time period, units to be converted to/from)
  • possibly a few generic setup codes and hardware buttons.
    • Way to set canbus ID externally but cant exactly have 11 switches to set it. 
    • send packet with configured ID when a button on the board pressed so you can see the ID in a capture.



Requests codes -> possible replies


Diagnostic codes start with 0


10###### External Hardware

Used to test physical connections eg cycle would create audible clicking from a relay 



11###### Internal ESP32 Hardware

Mostly useless but can log if think there are issues





Operational codes start with 0


00###### Manual triggered



01###### Automatic (must pass canbus ID for temp as next packet)





Anyone feel free to copy this and build your own version for non commercial use. 

Edited by Gripless
Link to comment
Share on other sites

  • Admin

This may be simple for you in your field but this seems way too techy for me.
ECU control is nice but could you not have some form of super basic controller with a contact thermometer on the backside of the intercooler outlet to let you know if temp is getting up and then have it run for a max amount of time and then shut off

Link to comment
Share on other sites

Very nice.

Used plenty of windscreen washers in bumpers before but those save the pissing about with a needle/pin to rotate the jet up and almost closed.

Even on lower lip their low profile still looks good so could run 4 if you wanted.


Nothing stopping reusing the headlight popup nozzles either so they would lower from top down towards middle of intercooler.


  • Like 1
Link to comment
Share on other sites

5 hours ago, Andy_Mac said:

This may be simple for you in your field but this seems way too techy for me.
ECU control is nice but could you not have some form of super basic controller with a contact thermometer on the backside of the intercooler outlet to let you know if temp is getting up and then have it run for a max amount of time and then shut off

Yes the basic one based on relays in that fuse box could be attached to a temp switch rather than a button.



Ok look at pretty diagram a few posts below for what this loooooog text looks like.



there are 4 relay timers that would stop the system running constantly until temp is low.



Idea would be to have temperature switch trigger relays eg


Unit power to 12v and ground.


temperature sensor connected to NC output of relay 2, and then relay 2 common to input 1


relay 1 NO output is connected to input 2,3,4

relay 3 NO output is pump

relay 4 NO output is solenoid if you want that

relay 1,3,4 common are 12v battery via fuse or fuses see below.



Temp switch triggers input 1 and then that would trigger input2,3,4

relay 2 then disconnects input 1 since NC becomes open for a time so waits for water to have effect, otherwise it runs nonstop until temp drops.

relay 3 runs pump 

relay 4 opens solenoid to allow water to jets or just does nothing.



Relay 1 only drives other relays, and relay 4 is solenoid so 3w. Pump is whatever wattage but likely higher than others.



1 just 1 second as just sets off others

2 time to wait before checking temp sensor again

3 pump run time should be shorter than timer 2

4 solenoid depending on how connected to pump or ignored.


would be best to also add switch between temp switch (or unit power) to cabin so you can choose if the system is on or off.


Just have to find a temperature switch in the range you want. They are common items for HVAC and for thermo fans in cars so plenty to choose from.

just for anyone in future. Relays with 5 pins

2 pins are to coil that switches the below.

NO is relay that tab that is normally and open circuit or disconnect until relay is active.

NC is opposite to NO, so circuit is connected until relay triggered.

Common is what NO and NC connect to. Can be 12v or ground or whatever you connect to it. 

Edited by Gripless
Picture is worth 1000 words so check posts below
Link to comment
Share on other sites

Pump depends on the jets you use:

windscreen or headlight washers are lower pressure

mist and irrigation are higher pressure


Hose needs to fit and hold pressure of:



Tee pieces 

one way valve. Needed for washer and high flow irrigation nozzles. Irrigation no drip while not one way do the same.


Link to comment
Share on other sites



MSword is slightly better than MSpaint


Things in drawing are:

Temperature switch, pump, solenoid.

4 Channel relay timer



Piping not shown



I'd add:

an indicator flasher relay between the solenoid and relay 4 NO connection for best efficiency and water savings.

Also fuses should go between battery and relay common for relay 1,3,4 based on cable and device size.

Heat-shrink and terminal fittings rather than bare wires etc



Solenoid can either

sit directly after pump and recirculate water back before pump


Sit between nozzles (or nozzle pairs if you run 4) so it alternates left/right or top/bottom for longer evaporation time




Edited by Gripless
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recent Status Updates

    • capada

      You are absolutely right. Declaring past debts to government agencies, even those that have been repaid, can be an important part of the application process for a variety of reasons. It shows financial responsibility and transparency. The same can be said for gambling, even casinos, which you can read about at https://www.slotozilla.com/nz/minimum-deposit-casino/1-dollar should also operate transparently. Of course, there are black casinos on the Internet, but they are not popular, because you never know whether you will withdraw money or not. If the form asks for information about past debts, it is usually best to disclose it, as this reflects honesty and can help establish trust in your financial information. Always read the specific instructions on the questionnaire carefully, as they will tell you what you need to specify.
      · 0 replies
    • MikeKolt

      Casino Portugal
      · 1 reply
    • MrSg9Sti04

      Afternoon team,
      im new to the group first time posting. Im hoping some body can help me get my launch control all dialled in on my link g4x. Ive had the computer and car all tuned from chris at prestige awesome knowlegable guy super happy with the results but now im wanting to get my launch/anti lag all dialled in. Ive been reading multiple different forums etc all with different conflicking information which has made me nervious with what do i listen to this or that if you get what i mean. Now ive started to make myself familiar with my PClink software etc the past few weeks and im eager to learn how to do minor setups or tweaks etc so im not relieing on my tuner so much and obviously saving myself abit hurt in the back pocket. 
      Now back to the question at hand.... Im wondering if theres and one who could please share there knowledge and wisdom with setting all my values, timing, fuel etc when i have launch control armed and engaged, or even a launch tune file they can possibly send me to load onto my tune. Ive figured out the setup of my digital inputs turning launch control on etc and its obvisously on its pre set factory settings. It engages but doesnt sound the greatest or as angry as it should i feel. Hence reaching out to you good buggers. 
      Cheers in advance for any info and help yous maybe able to give me.
      Cheers Shaun
      · 0 replies
    • Joker  »  gotasuby

      updated your DP's too : hope that's ok!
      · 0 replies
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Forum Statistics

    Total Topics
    Total Posts

  • Create New...