Water injection the Aquamist way
When buying water injection equipment your main consideration must be quality and reliability. Aquamist is the only product that comprises of precision-made components for the sole job of injecting water, each individual part is carefully selected and designed to work with water and alcohol mix. Aquamist has been extensively used in the top works WRC cars since 1997. Top names include Mitsubishi, Ford, Subaru, Skoda, SEAT and Hyundai plus countless numbers of privateers. The following "questions and answers" will unfold the mysteries behind the concept of the Aquamist water injection system.

Which Aquamist will suit my car?
All our kits are stand alone systems & can be fitted to any turbo or supercharged engine. We have three versions of water injection system:

• System 1s is triggered by boost only; the trigger point is determined by an adjustable pressure switch installed in the manifold (3-30psi).
• System 2c is designed for users with their own custom ECU, mainly for racing cars. System comes without an electronic controller. Apart from effectively cooling the inlet charge, water's main contribution is predominately used for in-cylinder cooling and detonation control. Once the detonation is under control, the boost can then be increased further to achieve more power gain.
• System 2s comes with an electronic controller (MF2), mappable between 2000-9000 RPM at 1000 intervals, load signal is either supplied by an adjustable pressure switch or a MAP sensor (not supplied) for a true 3-D mapping, water flow is progressive with pressure. The water line is pre-pressurised (adjustable between 4-8bars) at start up, flow quantity is regulated by a solenoid valve via MF2.

What effect does Methanol/water on fuel octane number?
By adding methanol to fuel the octane rating will go up. 10% methanol will increase the octane number by a factor of 5. When alcohol is diluted by mixing with water, the effect will be proportional to the concentration and flow of the water/alcohol mixture into the engine.

What type of Alcohol is not suitable for Aquamist?
Ethanol based alcohol should not be used with the Aquamist product. Trade names such as De-natured alcohol and Methylated Spirit is ethanol based. If in doubt, ethanol has a strong odour. Methanol or Iso-propanol should be used, they are low odour and perfect for used as an anti-freeze during winter.

Contents
1. My turbo car runs standard boost, would water injection increase the power output?
2. I would like to increase my power output by increasing the boost pressure, would water injection help then?
3. Should I upgrade my intercooler or get a water injection system first?
4. So I need to buy both at the same time?
5. I want to increase my boost pressure to maximise the full flow range of the original fuel injectors, would I then need water injection?
6. How much water do I need?
7. Can't I use a windshield water pump to do the same job?
8. How do I prevent the water from freezing in winter?
9. Why is Methanol better?
10. What is the maximum alcohol/ water ratio I should use?
11. How do I store 99.8% pure Methanol?
12. Can a handyman like myself install the Aquamist system?
13. How long does it take to install a System 2s?
14. My car uses a third party ECU, can I use the Aquamist system?
15. Do I need a different Aquamist system to the turbo kit?
16. I have a normally aspirated car, would water injection help me to obtain more power?
17. How do I advance the ignition timing?
18. My normally aspirated car suffers with sever detonation problem under heavy load such as towing, would water injection cure my detonation problem?
19. Would water injection help to improve the economy of my normally aspirated car, ie more mpg?
20. Is water injection effective on turbo diesels?
21. Do you have any practical example of a water injected vehicle?
22. Is water injection really necessary or it is just a new gimmick?
23. So what is the problem facing the performance orientated enthusiast today?
24. What is the solution then?
25. Is the Aquamist water injection idea based on scientific facts?
26. Why aren't there more force induced engines around?
27. Where does the heat come from?
28. Examining the heat source in detail ...
29. What does it all mean?
30. How much density increase if I were able to cool the charge air?
31. What is the current method of cooling the charge air?
32. Which is the best method?
33. There is just one more simple calculation to be made- the Mass Air Flow...
34. We shall see the effectiveness of an intercooler.
35. We shall see the intercooling properties of water injection.
36. Summarising the comparison...
37. Would water rust up my engine?
38. How wet is a rainy day or country with high humidity level then?
39. So what is the amount of water being ingested by an engine on a wet and rainy day?
40. Further Information

Turbo cars
1. My turbo car runs standard boost, would water injection increase the power output?
Water injection will not increase the power normally. In countries where the ambient temperature is very high, injecting water will lower the inlet charge temperature and produce a power increase.

2. I would like to increase my power output by increasing the boost pressure, would water injection help then?
It all depends; if you have good quality fuel and the ambient temperature is not too high you can with 2-3 psi of boost increase without using water injection and will not run into detonation problems. On the other hand, if you DO NOT have good quality fuel and the ambient temperature is high and there is a slight tendency to engine knock, water injection or a bigger intercooler is essential.

3. Should I upgrade my intercooler or get a water injection system first?
They do different jobs; intercoolers make the air denser and thus give more power. Unfortunately more power means higher combustion temperature and pressure, so water injection is becoming a more important addition to prevent the onset on detonation due to peak pressures and peak combustion temperatures. The natural progression would be to retain your stock intercooler and add water injection to supplement the existing cooling capacity of the stock system, charge temperature in particular. When you decided to go all out for big power, the entire system would have to be upgraded, not just the intercooler, turbo, up and down pipes etc. Water injection should definitely be included on your list of upgrade components.

4. So I need to buy both at the same time?
Ideally, yes. Given that water injection can cool the inlet temperature as well as suppressing detonation, water injection should be your prime consideration - an intercooler cannot perform in-cylinder cooling.

5. I want to increase my boost pressure to maximise the full flow range of the original fuel injectors, would I then need water injection?
Definitely yes, by stretching the fuel supply capacity to its limit, the Engine management would have lost its ability to dump fuel to assist the cooling of the combustion chamber, the running temperature will increase and soon bring about the onset of detonation and eventually lead to engine failure.

6. How much water do I need?
From the mild to the very wild, the quantity of water injected is normally between 10% to 25% related to fuel flow.

7. Can't I use a windshield water pump to do the same job?
No, the Aquamist system uses water pressure in excess of six bars, It is vitally important to atomise the water properly so each cylinder receives the same amount of water as well as performing intercooling in the inlet tract.

8. How do I prevent the water from freezing in winter?
Use a 20% Methanol/water mixture or use "windscreen additives" that contains Methanol, check it before purchase. Methanol is better than other forms of alcohol and is totally compatible with Aquamist products. Ethanol based type should be avoided

9. Why is Methanol better?
Methanol itself has an octane number of 113. Not only does it improve your fuel quality, it will also give you a better intercooling effect in the inlet tract.

10. What is the maximum alcohol/ water ratio I should use?
No more than 50%, otherwise you will increase the cylinder temperature rather than reducing it. Beyond that ratio, onset of detonation is more likely.

11. How do I store 99.8% pure Methanol?
Methanol is highly inflammable; store it in a well-ventilated place. It is better to dilute it with 50% water immediately before storing it.

12. Can a handyman like myself install the Aquamist system?
Yes, It will take approximately 2 hours, you need to drill a 7mm hole for the jet, a thread tapping tool is supplied with the kit. Make sure that the tip of the jet is protruding through the inner wall of the inlet tract or at least flush with the inner wall.

13. How long does it take to install a System 2s?
Approximately 5-6 hours, including setting up, a 20-page manual is supplied with the system.

14. My car uses a third party ECU, can I use the Aquamist system?
System 2C is specifically designed for such an application, you need to refer to the ECU manufacturer to provide an extra channel to drive the high-speed valve on the system 2C (13ohm). Check the competition "rule-book" before using water injection otherwise you risk being disqualified. Most WRC cars are based on that system.

Supercharged cars
15. Do I need a different Aquamist system to the turbo kit?
If you intend to install the water jet after the throttle plate, a 1-bar check valve must be purchased along with the kit (system1s only). This is due to the presence of vacuum, water can be siphoned pass the water pump under vacuum conditions.

Normally aspirated cars
16. I have a normally aspirated car, would water injection help me to obtain more power?
No, not in general unless you decided to increase the compression ratio, more advance ignition or run lower fuel grade than recommended by the manufacturer.

17. How do I advance the ignition timing?
Cars manufactured with a 'knock sensor' will automatically run more advance timing in the absence of knock. It is difficult to advance the timing on a car without a knock sensor built-in.

18. My normally aspirated car suffers with sever detonation problem under heavy load such as towing, would water injection cure my detonation problem?
Yes, water injection will minimise the onset of detonation or even totally eliminate it, but you don't necessarily need to use the Aquamist system as high water pressure is not required, a £5 washer pump and a water jet will work jet as well. Pay careful attention to prevent water from siphoning through the water pump during idle, a similar inline check-valve will do the job.

19. Would water injection help to improve the economy of my normally aspirated car, ie more mpg?
Water injection will enable you to run more ignition advance so you can achieve MBT timing (Maximum brake torque) thus improve the efficiency of the engine, mpg will increase as a result but you would need to carry a lot of water on board!

Turbo Diesel cars
20. Is water injection effective on turbo diesels?
Yes, Water injection can improve the torque output of the diesel engine, simply due to extra cylinder pressure during the evaporation of water. Further information can be provided on request.

21. Do you have any practical example of a water injected vehicle?
Not exactly, the only example we have encountered was a 11.5 litre, boost pressure of 4.6 bars (absolute) !!! The Skoda truck was run by a very dedicated team from the Czech Republic, and they are currently running in the European truck Championship. Since the installation of the twin-pump Aquamist water injection system, they have won the last three races of the season, third position was the highest they have achieved before the employment of Water Injection.

Common Scepticism
22. Is water injection really necessary or it is just a new gimmick?
Well, yes and no. For the old-fashioned traditional engine tuners with fixed ideas and blinkered outlook, water injection is regarded as an utter nonsense and a complete waste of time. Engines are designed to consume FUEL and not WATER. On the other side of the coin, engineers such as Sir Harry Ricardo (1930s) and bunch of aeronautic engineers (German, English and American) during the WWII (1940s) has found the positive side of injecting water into their supercharged fighter-plane engines. So the traditional began, Formula 1 engines (1980s) used it. We supplied the SAAB 9-5 an OE part and now World Rally cars use it (1995 onwards). We leave you to decide ... Whenever a problem is discovered; there is always a tendency to solve it, that is human nature. Old problems just keep re-surfacing, detonation, fuel quality; harmful emissions etc, despite the advancement of Electronics and Engineering materials available.

23. So what is the problem facing the performance orientated enthusiast today?
Money and Regulation constraint are the biggest hurdles. Works racing teams with big budgets have to obey constraints set down in the rule book, whereas street machines abide by no rules but are limited by cost as well as the legacy left by the original engine manufactures; Stringent emission legislation has pushed the engine manufacturers to come up with cleaner and more efficient engines. That means low compression engines are out and fuel efficient, high compression engines are in. Unfortunately fuel quality hasn't caught up, in fact it is getting worse.

24. What is the solution then?
Aquamist (1998 on) is putting forward one of the many solutions to solving cooling and detonation problems, it is not intended to replace good engineering and other cooling systems it just broaden the choice and gives people an alternative to intercooler upgrade, fuel dumping, low compression pistons and fitting ignition timing retardation devices.

25. Is the Aquamist water injection idea based on scientific facts?
Yes, we will try to explain the whole concept right from the beginning, starting with the basic engine dynamics. Please bear with us for the next few paragraphs before we get to the point. Lets for example look at the properties of a naturally aspirated 2-litre engine when it is turbo or supercharged, we shall see how the airflow characteristics change and how it is eventually translated into horsepower and the reasons for water injection. We first look at the intake cycle of a four-stroke engine, all results are calculated.

26. Why aren't there more force induced engines around?
Unfortunately there are a few drawbacks. Excess heat is one of the biggest problems which has haunted the turbo/supercharging systems for decades. Without heat problems, we can run higher compression ratio or lower octane fuel; no need for intercoolers or charge-coolers, no Aquamist, no heat stresses on engine components and most importantly, no heat-induced detonation problems.

27. Where does the heat come from?
Two main source of heat: when air is compressed, it just heats up naturally, compressor efficiency is the other, it can contribute over half of the total heat produced.

28. Examining the heat source in detail ...
This Chart shows the calculated compressor exit temperatures under different boost pressures.

29. What does it all mean?
Temperature rise affects air density. When the air is hot the density decreases and vice-versa when the air is cold. The proportion of the two densities is called density ratio.

30. How much density increase if I were able to cool the charge air?
Amazingly large increases, Chart shows the density increase as charge air is being cooled.

31. What is the current method of cooling the charge air?
Air/air Intercooler, Water/air charge-cooler is the most established way of cooling the charge air. Water injection has recently been re-introduced, It has been implemented on F1 cars (1980s) and currently is used by all the World Rally Championship Cars.

32. Which is the best method?
Having been kept waiting for so long, we'll be brief - Water injection of course! (we are biased). Before waving your arms in the air, lets be scientific and drop the hypes and hearsay and work it out mathematically...

33. There is just one more simple calculation to be made- the Mass Air Flow...
Chart shows a Mass Air consumption by a two litre engine up to 2 bar (pressure ratio of 3) boost. From the mass, we can calculate the efficiency of all three methods.

34. We shall see the effectiveness of an intercooler.
The efficiency of an intercooler relies on the following factors: 1) Frontal area. 2) Pressure drop across the cores (external and internal). 3) Road speed. 4) Air temperature differentials- (external and internal). To simplify the calculations, given that there are so many variations in size and efficiency we start with an intercooler with 50% efficiency. We will calculate how much heat is being removed for a given mass airflow based on a boost pressure ratio of 2 at 6000 rpm, using the same 2-litre engine. The result will be used to compare against a water injection system Ambient air temperature is 25øC and the compressor exit temperature is 124øC. At 50% intercooler efficiency (reasonable assumption as both the engine and intercooler is operating close to their peak flow limits), the temperature drop across the inter-cooler should be: (124øC - 25øC)/2 = 49.5øC. The final air temperature entering the engine is 74.5øC.

35. We shall see the intercooling properties of water injection.
Water temperature is 25øC and the compressor exit temperature is 124øC and Water flow rate of 250cc per minute. In the region we are working in the partial pressure of water vapour in the mixture is very low. We can assume that the enthalpy is a function of temperature alone within reasonable accuracy (e.g. for 250g /min of water and 8.64Kg/min of air, the partial pressure of water in about 0.06 bar). Consequently the final temperature is an inverse linear function of water proportional as nearest makes no difference. The calculation and results: At 200cc/min: 66.09øC At 250cc/min: 50.88øC At 300cc/min: 36.27øC So there we are, we have proved our point, water is just as effective as an intercooler. We decided to calculate a few more water flow rates so that a chart can be plotted, useful for visual prediction. Even at a modest flow rate of 200cc per minute, water is a better cooler than a 50% efficient intercooler by a long way. Notice at 350cc/minute of water, the final temperature dropped below the ambient of 25øC !!! there just isn't a 110% efficiency intercooler around yet ...

36. Summarising the comparison...
Before rushing out to buy an intercooler or make a water injection purchase please beware of the short comings of both systems, we listed a few here. Water injection will only be effective if it is injected in a form of mist, the droplet size is the key to a successful water injection system. Small droplet size increases the overall surface area, essential for good intercooling property. This is the reason why Aquamist uses line pressure over 7 bars.

37. Would water rust up my engine?
In our view, no more than average on a wet day. Lets put things in perspective, water is around us all the time whether you like it or not. It either exists as vapour or as puddles on the ground. Depends on the air temperature, the proportion changes, once the air can no longer absorb water, it forms minute droplets and eventually into liquid. The term "Relative Humidity" expresses that equilibrium, it spans between 0%-100% typically.

38. How wet is a rainy day or country with high humidity level then?
In rainy days, the relative humidity (RH) is over 90%, in the tropics (not raining) is often in the 80%.

39. So what is the amount of water being ingested by an engine on a wet and rainy day?
Chart shows the amount of water a 2-litre engine consumes on a typical 45% RH day, at 6000rpm, it draws in 150cc/minute of water.

40. Further Information
If you have any questions please email us at aquamist@interex.co.uk