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Water tank matters
1. Water tank size?
Generally about 5% to 10% capacity of the fuel tank, it will last approximately between every fuel filling.

2. What is regarded as the average water consumption?

3. Do I have to make a special tank for the water injection?
Most existing installations use the original windscreen washer tank. Some car makers even provide a low level warning lamp, which illuminates when water levels are getting low.

4. Would screen wash additive damage the Aquamist pump?
Our water pump is safe with most forms of alcohol. The screen additive normally contains a mixture of 5% detergent, 5% glycol and up to 50% of alcohol (methanol, or iso-propanol), the rest is water. Ethanol based alcohol is not recommended.

5. If I want to use a custom-made tank, can I put it at the back of the car?
Yes, with the exception of Porsche, Beetle etc. The lowest water level inside the tank should be higher than the water pump - especially if the horizontal distance is under 3.5 metres (11.5 feet).

6. What if the horizontal distance of the tank is over 3.5 metres and below the water pump?
You need a priming pump, any windscreen washer type will do it, needs to be activated under boost.

Inline filter positions
7. Should I put the inline stainless water filter?
The filter should be below the water tank, preferably immediately below the water level. If the filter is positioned above the water level, you might experience interrupted water delivery due to trapped air within the filter. Make sure that you can access it easily.

8. Can the water filter be cleaned?
Yes, back flushing is best, make sure that the trapped debris does not re-enter the system.

9. Where is the best place for the water pump?
In a dry area of the engine bay, the pump should be away from heat and vibration and not more than 0.5 metres above the lowest water supply level. It is important that it is not more than a metre away from the battery. Noise is also important, avoid fitting it near the bulkhead and large flat panel.

10. What if the pump is over two metres away from the battery?
Increase the gauge of the wire (standard loom is 16 AWG). We can supply heavier gauge cable loom for that purpose, let us know the length needed.

11. Can I fit the pump in an enclosed area?
Not really, semi-enclosed area must have ducted air-flow to assist cooling and bolt the pump body to the chassis properly to help transfer the heat produced by the pump.

12. Can the pump be fitted in any orientation?
Horizontal is best, but for road cars it can be fitted in any way you like.

Water jet locations
13. Where do I place the water jet?
Normally immediately after the intercooler unless the intercooler suffers from heat soaking such as the type that is fitted on top of the engine (Subaru, GTI-R, Toyota Celica and etc).

14. Surely if the jet is placed before the intercooler it will have better cooling effects?
Not quite true. If the air entering the intercooler is pre-cooled, the cooling efficiency of the intercooler will drop due to the smaller temperature differentials between the ambient air and induction air within the intercooler core. Secondly, there is also a possibility that the hot air from the turbo may cause unnecessary vaporisation of the injected water thus taking up precious volume that was intended for the charge air.

15. Should the water jet be facing the direction of the in-coming air?
Two possible locations, if the jet is to be installed along an induction pipe, point it at 90 degrees to the direction of the air flow. Position the jet furthest away from the throttle body as this will enable better mixing and intercooling properties. If the jet is installed at the end-tank of the intercooler, point the jet in such a way that it has the greatest cavity to accommodate the 90 degree spray pattern.

16. How do I stop the water being siphoned into the inlet manifold during idle as I have to install the jet after the throttle body?
You need to install an inline check-valve (806-249), it has a crack pressure of 1 bar, so the vacuum can not overcome the valve.

17. Is it possible for the water to siphon into the engine during the non-running period?
Under normal conditions, the inline pump acts as a stop valve, only under pressures over 2 psi will the water pass through the pump. This condition is unlikely unless your water tank is 10 feet above the water jet.

Pressure switch
18. Can I use the pressure switch to switch on a dash led?
Yes, a dash board led can be connected in parallel to the switch to indicate the switch point, no inline resistor is necessary Please note that it doesn't mean that water is being injected

19. Where is the best position to fit a pressure switch?
Along the inlet tract or manifold, but well away from heat and vibration. The setting of the pressure switch can be affected by heat. We now include the remote mounting kit in systems.

Pump in trunk?
20. Is it possible for the water pump to be located in the trunk (opposite end of the car?
Unless there is absolutely no alternative, the pump should always be by the engine bay.

21. What if there are no other alternatives?
You need to double the size of the electrical cable to the pump or a loss of performance will result, this due to voltage drop in the cable as the pump is not receiving maximum current from the battery. (this is true if the battery is at the opposite end of the car).

22. Is there another way other than increasing the size of the cable?
Yes, fit a small rechargeable battery near to the water pump (6.5 AHr-lead acid) will do it. The battery will supply the peak current to the pump (28A for 1ms)and retains the peak performance of the pump.

Aquamist safeguards
23. What will happen to the pump if the water tank is empty?
You have got approximately three minutes before permanent damage occurs. Please note that this rarely happens as three minutes is an awfully long time to keep your foot down on a normal road. Track racers need to take great care not to allow this to happen.

24. How do I prevent this from happening?
Treat water injection as part of your standard OE equipment, check the water level regularly, fitting a water pressure gauge is the first step. Monitoring the water pressure has other advantages such as early warning of a blocked jet, if the water pressure is progressively increased for no reason, it is a sign of the beginning of a blockage.

25. I would like to fit a better looking gauge rather than your 'purely' functional type, will an oil gauge do?
Yes, most 10-bar+ oil pressure gauges are constructed with brass fittings and are suitable for water applications. Please note that an inline restrictor must be used to prevent damage to the gauge by the high pressure pulses by the piston-action pump. We can supply most fittings to match the thread fitting of common oil gauges, contact us with the thread fitting details, do not guess.

26. I would like an early warning system rather than a gauge, any suggestion?
We supply an external-fit float switch, it is very easy to fit, available with LED warning lamp as an option.

27. Is that an active or automatic way of stopping the water pump running dry?
Yes, there are a number of ways you can do it:

28. I would like to fit an indicator to tell me when the pump is activated
Circuit diagram shows how this can be done.

Engine safeguard
29. How do I protect the engine from the absence of water?
The modern engine protects itself by either retarding the ignition timing and injecting more fuel when detonation is detected by the onboard knock sensor and extreme in-take air temperatures. The effect of the water injection is very similar to putting in a tank full of high-octane fuel, engine management has in-build intelligence to adjust itself to achieve optimum operating perimeter to suit the fuel.

30. What if my engine management cannot perform such a strategy in the absence of water
There are a number of ways to achieve the same aim as the car manufacturer. In the absence of water (by fitting a float sensor), we can use the following strategies:

1) Reducing Boost pressure:
a) System 1s
Instead of using a manual bleed-valve, replace it with a electro-mechanical solenoid valve. When 12v is applied to the valve, the boost is artificially increased by venting some of the air going into the wastegate. Upon detecting the absence of water (float switch), interrupt the 12 volt supply to the valve to return the boost pressure back to standard.

b) System 2s (MF2)
Diagram 1:

Diagram 2:

Diagram 3:

2) Dumping fuel:
Most Fuel injected engines increase fuel delivery when the engine senses low engine block temperature. It is possible to fool the engine into thinking that the engine block is cold whilst the engine is fully warmed up so more fuel is being injected . The float sensor can now be used to pull the voltage of the sensor up to a point that more fuel is being injected but not flooding the engine- this a done by putting an inline resistor, value to be optimised for your own particular engine, try a 1K ohm resistor first If you already used a float sensor for other functions, then add a multi-pole relay. This strategy is particularly useful for supercharged engines where controlling the boost is not possible.