E39 M5 Vanos
The Variable Nockenwellen Steuerung or Vanos is an automobile variable valve technology, which was developed by BMW, in collaboration with Continental Teves in 1992 and has been refined over the years to its present day “double Vanos” configuration used in both the E39 m5 and the E60 M5.
Vanos is defined as the combined hydraulic and mechanical camshaft control device directed by the car’s DME/ ECU engine management system. The Vanos system is based on a separate adjustment mechanism that can alter the location of the intake camshaft versus the crankshaft around a helical gear. In the single Vanos, this movement varies from 6 degrees of advanced to 6 degrees of retarded camshaft timing.
It should be noted that the relationship between the rotation of the camshaft and the rotation of the crankshaft is of crucial importance here. That is because the valves control the flow of air/fuel mixture intake and exhaust gases. This is the reason why they must be opened and closed at the proper time during the stroke of the piston.
Subsequently in 1996, the double Vanos technology was used in some BMW models. This technology further improved engine performance. All E39 M5 models, which were first released in 1999, were fitted with the double Vanos technology and the performance delivered from the s62 v8 engine was simply astounding in terms of throttle response and torque curve.
The double Vanos technology changed the single Vanos mechanism from fixed position operation to continuously changeable for BOTH the exhaust and the intake camshaft. Adding the same efficiency to the exhaust camshaft – makes it an incredible design.
On the double Vanos system, the timing of the intake and exhaust cams is constantly changeable through a range of ~40 crankshaft degrees for the intake, and 25 degrees for the exhaust. The advantage of double Vanos is that it controls the flow of hot exhaust gases into the intake manifold individually, this means that incredibly fine degrees of performance are attainable. And this goes for all operating conditions of the system. By changing the camshaft timing, it optimizes power output all throughout the range of revolutions. In other words, whatever speed you are in, you will have markedly better engine performance, improved fuel efficiency as well as lower emissions.
This is because the double Vanos controls the amount of exhaust gas that is re-circulated back to the intake manifold. It does the job by using a particular set of parameters in the engine’s warming-up phase, which for the s62 are noted with a decreasing LED tachometer system telling the driver not to over-rev the engine until it is warmed up. The desired effect is for the cylinder heads, oil and catalytic converter to achieve their ideal operating temperatures quickly, which helps in decreasing gas emission.
In summary, here’s how the double Vanos works. While the engine is warming up, it improves the fuel/air mixture and quickly warms up the catalytic converter to its normal operating temperature. While the engine is idling, it keeps idle speed smooth and consistent due to the reduction of exhaust gas re-circulation to a minimum. At part load, exhaust gas re-circulation is increased to a much higher level, letting the engine run on a wider opening angle of the throttle butterfly. Under full load, the system switches back to a low re-circulation volume providing the cylinders with as much oxygen to mix with the increased fuel flow as possible. This, in conjunction with the air flow sensors provides for a stunning performance from the Vanos system.
The result is an engine that uses energy in the most efficient way possible, which creating the most horsepower possible. For a naturally aspirated engine – you REALLY have to give it up for BMW as they’ve truly build an impressive piece of technology with the double vanos system used in the BMW E39 m5.
Over time the solenoids and the seals around them to tend to wear out – but these issues are relatively easy to repair. Some people don’t like the rattling noise that the Vanos system makes – but it actually has no impact on performance or longevity – even though some people have them fixed with after market repair kits and post 2001 E39 m5’s had improved Vanos systems with tighter tolerances because customers complained in the first few years of production. The Vanos system in the E39 m5 is built with a design tolerance which allows for the movement of parts in a way that creates a ‘diesel’ engine sound at idle.
The Vanos system can thus be described in one word: precision. You can be sure that the BMW E39 M5 can accelerate at any time, with immediate feedback from throttle response.