How To Get Turbo Flutter On BMW Diesel?

Start the engine and stroll around the vehicle as the driver revs it up. Widen the cut by about one-third of the pipe’s circumference to increase the depth. Additional cuts spaced four inches apart might be used to provide depth and volume to the sound.

Is turbo flutter harmful to the engine?

When compressed air has nowhere to go, the turbo’s rotational speed drops rapidly, and it tries to push against the wheel. Closed throttle flutter on modern turbochargers can cause premature wear, but it is unlikely to result in a significant reduction in turbocharger lifespan.

What causes the fluttering of a diesel engine?

The fluttering sounds is the sound of a turbo in compressor surge, which occurs when the compressor ‘chops’ through the air rather than forcing it into the engine. Whether you like it or not, it’s not helping your turbocharger’s performance or reliability.

A blow-off valve comes in handy in this situation. Between the turbocharger and the throttle body, these are installed. The closer they are to the throttle body, the better, because proximity improves surge mitigation reaction.

The blow-off valve’s purpose is to prevent compressor surge. When there is a sudden change in engine load from boost to vacuum, such as when a throttle plate closes, it opens as soon as it can to do this. The open valve keeps air flowing through the charge pipe, preventing a pressure rise and allowing the turbo to stay in the ‘zone’ without going over the surge line (see to the graph above).

When the throttle is opened again, an appropriate blow-off valve will open quickly enough and have enough flow capacity to avoid compressor surge, while also closing and sealing quickly enough to produce boost and enhance throttle response and acceleration.

Because shaft speeds are modest at low boost levels, the influence of compressor surge is minor. In fact, many vent-to-atmosphere BOVs will still experience a minor surge because the engine produces insufficient vacuum at low revs to open the valve. Compressor surge, on the other hand, should be avoided when shaft speeds increase.

Many early factory turbo cars, which tended to run low-pressure turbos, did not have blow-off valves at all; however, as technology and understanding of it has improved, these valves have become standard fitment from the manufacturer, and simply vent the air back into the inlet system (recirculating it) in front of the turbo for reuse.

The limits of factory-installed valves, on the other hand, are well acknowledged. They’re frequently composed of plastic, which becomes brittle and fractures over time as a result of heat cycling. They rely on rubber diaphragms, which age and fail again, and they can’t handle boost increases when doing minor improvements, and they can’t manage the flow when doing significant upgrades.

What’s the best way to make my diesel sound like a V8?

One of the best modifications for diesel or electric cars is a sound Booster. The Sound Booster transforms your vehicle into a powerful petrol engine. One of the most common complaints we get from diesel car owners is that the vehicle produces no sound, which makes for a dull journey. Some people have followed the advice of unqualified experts and removed all silencers from the exhaust system. Making it a straight pipe system, which they later regret owing to drone concerns; some even go so far as to remove the DPF (making the car illegal to drive on public roads). Wouldn’t it be fantastic if a diesel car could sound as thrilling as a high-powered petrol engine? Now, however, there is an alternative: a Sound Booster.

Modern diesel automobiles can be equipped with a sound enhancer that simulates the sound of a powerful V8 petrol engine. A sound booster is made of of a module that connects to the vehicle’s ECU and a sound box that emits the tone. It takes a day to install and works in tandem with the engine, so every acceleration amplifies the sound.

So far, we’ve installed over 100 units with excellent results. It’s similar to a mechanism used in Maserati diesel vehicles. There are about five noises to choose from through remote control, depending on your mood; turn it off, and you’re back to a typical diesel sound. Another advantage of this module is that it may be moved to a different vehicle.


These devices, sometimes known as diverter valves, have nothing to do with boost control. When you swiftly lift off the gas pedal, you’ll hear blow-off valves and diverter valves. When the throttle blade (the flap that rotates when you move the gas pedal) shuts, they release boost pressure. The swiftly moving air escapes through the blow-off valve because it has nowhere else to go. A basic valve with a spring to seal the valve and a vacuum reference from the intake manifold are used in these devices. The BOV opens when there is vacuum (no boost) in the intake manifold compared to the rest of the intake system.

Is turbo flutter beneficial?

When you step off the gas pedal after reaching full boost, turbo flutter, also known as compressor surge, happens. While the engine’s airflow is cut off, the turbo’s pressure is still present and hunting for a way out.

Because the sole path of least resistance is directly back through the turbo, turbo flutter is caused by backpressure.

The blow-off valve is a component that most manufacturers use to eliminate turbo flutter (BOV). However, if you start tinkering with your setup, such as installing an aftermarket BOV with a firmer spring or removing your blow-off valve entirely, turbo flutter can occur when pressure forces its way back through the turbo.

Despite the fact that turbo flutter makes a lot of noise, it has no effect on performance! Backpressure after you release the throttle is the reason for this. In other words, turbo flutter occurs after the engine has completed its task.

The Role of a Blow-off Valve vs Wastegate

Many people mix up blow-off valves and wastegates, although while they look similar, they serve completely different purposes and are used for entirely different reasons.

Blower-off valves, as previously stated, are used to eliminate turbo-flutter. They’re located on the turbo’s intake side and are generally closed. When a BOV detects too much pressure in the intake past the turbo, it opens up and lets it out.

This pressure is either vented into the atmosphere or redirected back into your vehicle’s intake, depending on the type of BOV in question.

Meanwhile, wastegates on the turbo’s exhaust side prevent it from producing too much boost. Once the turbo reaches the desired boost level, they direct exhaust pressure around the turbine inside the turbo.

While both wastegates and blow-off valves channel excess pressure, the difference between the two is where the pressure is directed and why it is directed.

Wastegates keep the turbo from creating too much boost, while a BOV keeps the turbo safe from the pressure created by the boost.

What is a turbo surge, exactly?

Turbocharger surging is characterized as a high-pitched, audible vibration coming from the turbocharger’s blower or compressor end.

It’s common in low-speed diesel engines, and any sea-going marine engineer has probably heard this howling sound at least once during his or her time at sea.

Surging happens when the turbocharger’s gas flow breaks down, causing a reversal of scavenging air via the diffuser and impeller blades into the blower side.

Simply put, a large mass of oscillating airflow can induce vibration of the turbo compressor impeller and vanes, preventing the compressor from operating smoothly and, as a result, producing a high-pitched noise known as compressor surge.

Other terms like turbo surge or engine surge may be used to describe this event, although the turbocharger or turbo-compressor compressor is the directly involved component that is surging.

The turbocharger’s turbine side, or exhaust gas side, has no direct impact on the surging process. It will surely impair the overall performance of the turbocharger, maybe resulting in turbocharger surging.

Surging may occur during engine operation at sea due to external circumstances such as sea state, weather, rapid manoeuvring, crash stops, and so on. Compressor surges of this nature are permissible.

The ship’s engineer, on the other hand, must guarantee that the turbocharger bearing and lubrication fluid are in good working order.

If the surging occurs during normal engine operation and the frequency of the surge is excessive, it can damage the bearing and, in some situations, cause the compressor rotor to fail mechanically. As a result, the turbocharger surging is caused by a lack of coordination among various engine components.

Engine and turbocharger difficulties might be caused by a worn-out engine cylinder or fuel system. As a result of the reduced airflow to the compressor and the increased back pressure, the compressor will surge.

As a result, turbochargers must be appropriately matched to the engine’s air consumption rate and pressure throughout the engine’s working range, and should not exceed the surge limitations.

What’s the best way to make a diesel sound sporty?

Fortunately, a sound enhancer can make a diesel car seem more athletic. A sound booster is an aftermarket device that duplicates the sound of a sports car’s engine and exhaust. This provides drivers with the sound and aesthetic they desire, regardless of the vehicle they are driving.

What’s the secret to getting the BOV flutter sound?

The BOV isn’t performing its job if the automobile makes a fluttering noise when venting at high rpm and boost. Contrary to popular perception, the noise is produced by the turbo rather than the BOV.

Certain cars (as described above) exhibit non-detrimental low-rpm fluttering when an aftermarket BOV is installed, especially when a larger turbo and intercooler are installed.

When venting a considerable amount of boost, the valve should create a clean PSSSH or Whoosh sound when properly adjusted. Increase the spring preload by turning the adjuster clockwise if you want your BOV to flutter a little. As long as your BOV vents with a whoosh at high rpm and boost, it’s totally okay to set it up to generate some low-rpm flutter.