Sunday 9rd May 2021

Popular noise with big disadvantages - Turbo flutter

Reading time approx. 4 Minutes

Turbo flapping flutters tuning e1560247023252 Popular noise with big disadvantages turbo flapping

The opening of the diverter valve via vacuum sucks charge air. The excess charge air is blown out via a hose, which leads to a hissing noise. If the diverter valve is broken, the turbocharger makes a noticeable noise and that Pop-off valve flutters. In this case, the excess charge air is drained through the turbocharger. This is not healthy for the engine. The air pressure moving in the other direction, which is returned through the turbo inlet, creates a condition called turbo fluttering. The paddle wheel is rotated in a different direction during turbo fluttering or turbo flutter. Of course, it has to be slowed down first. Braking the paddle wheel generates the typical “fluttering” noises. Braking puts extreme stress on the bearings. The bearings cannot withstand the heavy loads for long and break prematurely. That means the end for the turbocharger.

What is the so-called turbo flapping?

Turbo flapping flutters tuning 2 e1560247128194 Popular noise with big disadvantages turbo flapping

When there is excess pressurized air in the turbocharger system, turbo flapping occurs, which is also called compressor surge. If the engine is unable to burn the entire amount of air that comes through the turbocharger, the excess air is built up in the intercooler. When the pressure in the intercooler increases with the pressure in the turbocharger, the air is forced back through the turbocharger inlet. The paddle wheel of the turbocharger is braked and moved in the other direction. Even with oversized turbochargers may cause a turbo flutter, since the engine is not able to burn the entire amount of air at low speeds.

Blow off valves

Blow Off Valve Thrust Recirculation Pop Off Tuning Popular noise with big disadvantages Turbo flutter

Here you should first know what a blow-off valve is. It is currently a very much desired tuning part. But many have only half knowledge about it. But what does the blow-off valve really do and what exactly does it do? What variations are there and what are pros and cons.
For one thing, there are closed systems. The blow-off valve directs the boost pressure of the turbocharger, which arises when leaving the gas pedal and the throttle valve wants to back into the intake. Here it does not come to the typical hiss. The hissing occurs only with open blow-off valves, as they let out the boost pressure. With the closed blow-off valve, the measured values ​​of the air mass meter are not distorted. It's different when it's open Blow off valveSince this leaves the air out, the lambda sensors measure lower values. As a result, the idle speed is increased. The idle controller then tries to lower the idle speed again. And it creates again negative pressure. This circle keeps repeating itself. An alternative to producing the coveted hissing sound is to make it over an open suction. Or you increase the preload of the spring of the piston, then there is enough force there to keep that open blow-off valve closed even at idle speed.

Popular noise with big disadvantages

We hope you the info report to the term Turbo flutter from the field of autotuning. Our goal is that the largest German-language tuning dictionary (Tuning Wikipedia) and to explain tuning terms from A to Z easily and understandably. Almost every day we expand this encyclopedia and how far we are already can you HERE see. Soon the next one will be Tuning scene concept be illuminated by us. Incidentally, you will be informed about new topics if you have ours Feed subscribe to.

Below are a few examples from our tuning lexicon:

But of course tuningblog has countless other articles on the subject of cars & car tuning in stock. Do you want to see them all? Just click HERE and look around. But we also want to provide you with news outside the tuning. In our category Tips, products, information & Co we pick up contributions from car or accessory manufacturers. And also our category Test sites, laws, offenses, information has almost daily new information for you. Here are a few topics from our tuning wiki:

Detail work in the cabin - individual door pins for the car

T% C3% BCrpins T% C3% BCr Locking Pins Doorpins Tuning4 310x165 Popular noise with big disadvantages Turbo Flutter

If crazy is not enough: Bosozoku Style Tuning from Japan

Bosozoku tuning B% C5% 8Ds% C5% 8Dzoku Term 310x165 Popular noise with big disadvantages turbo flapping

Tip: Carbon cardan shafts for powerful vehicles

Carbon propeller shaft tuning aluminum 3 310x165 Popular noise with big disadvantages Turbo flutter

Eye-catcher - door projectors and entrance lighting

T% C3% BCprojectors Entrance lighting Tuning 310x165 Popular noise with big disadvantages Turbo flutter

Cool: tuning shift knobs and gear selector for the car

Tuning gear knob W% C3% A4 lever Gear lever e1559904507676 310x165 Popular noise with big disadvantages Turbo flutter

What is a wastegate (bypass valve) and what do you need it for?

Wastegate Bypass Valve Tuning e1560158490593 310x165 Popular noise with big disadvantages Turbo Flutter

"" - we keep you up to date on the subject of car tuning and car styling with our tuning magazine and present you the latest tuned vehicles from all over the world every day. It's best to subscribe to ours Feed and will automatically be informed as soon as there is something new for this post, and of course also to all other contributions.

Smava tuning blog credit 12 e1618563898711 Popular noise with major disadvantages turbo flutter

You might also be interested in…         by


  1. How does the turbo flutter behave with a diesel !? Since there is no throttle valve there! Is it just as harmful to the engine !? And with a Stade 2 the bearings should be able to withstand it, right?

  2. I'm not a professional myself, but I had someone explain to me that the turbocharger does not turn in the other direction if you remove the "blow off valve". It's just not physically possible. the turbo flutter does not come from the turbo rotating in the wrong direction. the turbocharger only slows down and there is a very low “boost lag” (you will not even notice it).
    Conclusion: 1. The engine does not suffer any damage. 2. There are so many cars that are equipped with good turbochargers installed by good tuners and that generate this notorious turbo flood. Take a look at rally cars, they have that sound too. I can also say from first hand that, with properly installed turbos, there will be no problems if you remove the "blow off valve".
    If you are still not sure, I would go to the mechanic or to the tuner right away and ask what their opinion is.
    I hope I could give you some clarity.
    Kind regards. Nils

Leave a Comment

Your e-mail address will not be published.