BMW Cars

How BMW Used Water To Make +50 Horsepower

How Water Injections Systems Can Create More Horsepower A Detailed Explanation Of BMW’s M4 GTS Water Injection Engine .

The BMW M4 GTS is one of very few production cars to ever be fitted with a water injection system, used to take the twin-turbo I6 engine from 444 Horsepower up to 493 horsepower, using the beauty of evaporating water to do so !

From BMW, here’s how it all works :

First See the video below then read the article 🙂

Water is injected as a fine spray into the intake manifold plenum chamber where it evaporates, significantly lowering the temperature of the intake air.

This reduces the final compression temperature in the combustion chamber, which also reduces the risk of knock, allowing the turbocharged engine to operate with higher boost pressure and earlier spark timing. The result is increased power and torque, and a substantial improvement in efficiency.

Despite the extra power output, thermal stress on all performance-related components is reduced. All of these features ultimately help to diminish wear and prolong engine life. The benefits of water injection can be utilised in various ways, depending on engine and vehicle type.

In particular the engineers have considerable latitude when deciding how to balance their priorities between increased power and fuel efficiency. If water injection is taken into account in the design of a high-performance engine right from the start, it is possible to use turbochargers with a higher boost ratio and compression ratio.

Water injection provides a particularly effective way of raising the knock threshold in this range, allowing the compression ratio to be increased. This makes it possible to optimise the power output of the turbocharged engine over a wide operating range. The lower the octane rating of the fuel, the greater the potential of this technology.

In terms of practical implementation, the BMW M division’s engineers opted for an arrangement whereby three water injectors in the intake plenum chamber each supply water to two of the straight-six engine’s cylinders. This solution makes for uniform water distribution and a compact system design.

On safety grounds, the BMW M water injection system is equipped with a sophisticated self-diagnosis system. If the water tank runs dry, or in the event of a system malfunction, appropriate measures are taken to protect the engine.

Boost pressure is reduced and the spark timing is retarded, allowing the engine to continue to operate safely at reduced power. Even when things are working normally, a variety of precautions are taken to keep the system fully functional.

Every time the engine is switched off, all the water in the hose system is drained into the tank to prevent system components from icing up in sub-zero temperatures. The water tank is likewise frost-proof.

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