On the road during lockdown

Here's what motorists should know.

Meet Smokey Nagata

The man behind the legendary twin-turbo V12 Toyota Supra build.

WATCH: Why the 'stu tu tu' noise from your turbo might sound cool but isn't good for your engine

2019-02-19 20:00

Robin Classen


Image: iStock

Nothing brings a smile to the face quite like the 'whoosh' sound emanating from a turbocharger once you let off the throttle ; this coming from driving shotgun and also being behind the wheel of a tuned S14 Nissan Silvia.

Flutter talk

I've recently been scouring the internet as part of research to lay the foundation for my very own SR20DET build and came across numerous videos focusing on turbo flutter.

READ: Smokey Nagata: The man who created the legendary twin-turbo V12 Toyota Supra build

Check out the video explaining compressor surge:

I've always wondered how some guys achieved that 'stu tu tu' noise as opposed to the 'whoosh' because it sounds downright cool. Some liken it to a loud pigeon or bird gobble.

One particular video by the guys from Go Fast Brett  explained what is known as compressor surge and the analogy behind it is very interesting indeed.

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The basic concept behind this surge is when the incoming air has no place to be released once the throttle has been closed, which is normally done so through the blow-off valve, and then gets recycled back into the turbo.

The conflicting back and forth air pressures in the turbo has no place to go but expelled through the turbo and lets off the 'stu tu tu' sound.

So does it make the car faster?

The simple answer here is no. Most people only tend to do it because it sounds awesome and also letting the guy next to you know you mean business.

In essence, what you are doing is removing a part in how a turbo normally operates and re-configuring it in a way to not need it.

Can it harm the engine? No, but it can do a number on the turbo over time especially if you are running high boost. The compressor blades can run down over time which also provides the opportunity to fit a bigger turbo.

What to do if you hear 'stu tu tu'?

This could mean one of two things, either your wastegate or blow-off valve isn't releasing a sufficient amount of pressure or you are running too much boost on the stock turbo.

Tuning down the boost or fitting a higher pressure BOV can remedy the situation and return the 'whoosh' sound.

There are no benefits to gain from this sort of modification because that is what it essentially is, a modification.

Forced induction is like a form of black art that can either make you really happy or staring down the barrel and thinking 'why did I do this'. Turbo builds will always be the more expensive as opposed to their naturally aspirated counterparts but you sure as hell get your monies worth when everything clicks into place.

Personally, I really like the 'stu tu tu' sound but I would much rather source all the parts needed instead of sacrificing here and there for the sake of a sound that won't improve performance.

Read more on:    nissan  |  robin classen  |  guide and lists  |  turbo

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