All about water injection
All about water injection - You need to know!
Water injection is a popular method of increasing performance that promises extreme results: firstly for the performance and secondly for fuel consumption. Mostly there is talk of up to forty percent more power! Reason enough to take a closer look at the subject. Here you can find out everything you need to know about water injection in tuning. Nice to know: The technology of water injection comes from aviation, where it led to an increase in power from 1700 to 2400 PS in a German fighter plane. Of course, what's in it for your engine depends on several factors.
- 1. Definition of water injection - What is it actually?
- 2. How does water injection work exactly?
- 3. What are the benefits of water injection?
- 4. Injection: Only water or water-alcohol as coolant?
- 5. These are the advantages of water injection for tuning at a glance
- 6. Disadvantages of water injection
- 7. Water injection and TÜV
- 8. Conclusion
Definition of water injection - What is it actually?
Water injection is used to cool the fuel-air mixture and thus achieve more power and lower consumption. In most cases, very finely atomized water or a water-alcohol mixture (WAES technology) is injected into the combustion chamber. Another possibility is to spray the charge air cooler with water from the outside and thus cool the charge air.
How does water injection work exactly?
Water injection, or water-ethanol injection, starts behind the turbocharger. The water or water-alcohol mixture is injected into the compressed air. This happens at a certain boost pressure and with high pressure of the water. This comes from a corresponding tank (but can also be fed from the windscreen wiper system tank) and is sucked in via a high-pressure piston pump. The charge air is thereby extremely cooled down and compressed and also the combustion chamber is cooled.
The water is atomized by a special nozzle. What arrives in the engine is therefore not comparable to the morning shower: We are talking here about extremely fine water vapor. Water absorbs a lot of energy (heat) during evaporation. We are also talking about evaporative cooling here. The atomized water is injected into the combustion chamber via a valve. Depending on the system, the amount of water injected is static or is regulated proportionally to the boost pressure. In this way, the optimum quantity is always injected.
Similar to the intercooler, water-alcohol injection cools down the air-fuel mixture. In doing so, we want to increase the density and oxygen content in order to be able to burn more mixture and thus increase performance. With WAES technology, however, the knock resistance is also extremely increased. As a result, we achieve higher boost pressure and earlier ignition. Especially when we inject ethanol in addition to water, knock is extremely reduced.
What are the benefits of water injection?
Especially with tuned engines, which are also exposed to more heat due to the high power, water injection can provide relief. Any heat build-up can be compensated for via the injection quantity. Sophisticated systems keep the corresponding control system in the interior of your car ready for this. How much more power you can achieve depends on the components installed, especially the power of your turbocharger. With an appropriately powerful turbo with a high-performance turbine, you can achieve an increase in output of a whopping 40%! Consumption and pollutant emissions are also reduced by water injection.
In contrast to charge air cooling, water injection does not cause a loss of boost pressure. This occurs with conventional charge air cooling due to external factors such as the ambient temperature or the size of the LLK. If these limits are reached, there is no more additional power, the engine begins to knock and engine damage is inevitable. Water injection knows no limits here and can also cool the temperature of the charge air below that of the environment. The most efficient way is of course the combination of a upgrade intercooler and an efficient water injection system.
Especially if you have already taken tuning measures, the water injection is a great addition. Because of the increased performance you also need an improved cooling. The thermal load is reduced considerably and the engine is protected.
Injection: Only water or water-alcohol as coolant?
Basically, only water or a mixture of water and alcohol (usually ethanol or methanol) can be used for water injection. If you use only water for injection and cooling, you have to pay attention to a few things: In the best case, it should be distilled to avoid lime deposits. These could clog the nozzles and contaminate the combustion chamber. If you use a mixture of water and methanol, you can expect by far the highest additional performance. This is mixed in a ratio of 70 (water) to 30 (methanol). With ethanol the ratio is 50:50, this is also easier to obtain, but the increase in performance is somewhat lower. By using methanol you also prevent the formation of oil carbon in the combustion chamber.
These are the advantages of water injection for tuning at a glance
- Super addition to previous tuning measures (chip tuning etc.)
- Active cooling of the combustion
- Significantly reduces engine knock
- Increases boost pressure/ignition timing in a safe way
- Thermal load for the engine is extremely reduced
- No loss of boost pressure and optimal efficiency
- Power loss at higher outside temperatures is compensated for
- Charge air temperature can be reduced below that of the environment
- Specific consumption is reduced
- Exhaust gas temperature is lowered, turbocharger is protected
- With extreme efficiency, an intercooler can even be dispensed with
Disadvantages of water injection
There is no explicit disadvantage of water injection. Of course, the system has to be maintained in so far as there is always enough fluid available. You should therefore make sure that you have a fluid gauge in the interior to prevent it from running dry. It should also be possible to switch off the piston pressure pump so that it cannot run dry when the tank is empty. If you want to use the full potential, you probably want to use methanol. But this is not so easy to get.
Water injection and TÜV
Unfortunately, you can't expect your water injection system to be approved for public use. These systems are mainly produced for motorsport and therefore come without ABE.
Conclusion
For racing fans and ambitious tuners, water injection systems bring a significant increase in performance and various advantages that we do not want to withhold from you: Up to 40 percent more power, less consumption, engine protection and so on. The few disadvantages are in no relation to this, as long as we do not rely on the general operating permit.