Ds3 dsport 1.6 diesel turbo chatter

[Jd96ds3]

I was looking to put a blow off valve on my diesel ds3 however I've read that the blow off valves on the petrol engines, does anyone know how to get turbo chatter on the diesel models?

[BenS]

Wait, do you want turbo flutter or a blow off valve? BOV = buy a loud aftermarket one as the factory fitted ones are silent. Flutter = bypass your factory BOV. To be honest, the turbos in DS3s are so small and run such low boost pressures you probably won't hear much in either case unless you remap to a higher boost pressure.

[WTF]

Yeah, they are two different things as Ben mentioned.

Liam's THP achieved a good Turbo flutter <3

But you will struggle to a decent BOV for the diesel.


Diesels don't have a wastegate - this article is quite good - http://www.dieselarmy.com/engine-tec...ff-valves-bov/

A blow off valve or dump valve is used on a turbo PETROL engine. A petrol engine has a throttle butterfly valve which blocks the inlet when you take your foot off the accelerator. When you do this, the pressurized air from the turbo has nowhere to go. Without a blow off valve, the back pressure can cause the turbo compressor to slow or stall. When you try to accelerate again, the turbo has to spin up to speed again which creates lag or a flat spot.

With a blow off valve fitted, when the throttle is closed, the blow off valve vents the boosted air so that the turbo compressor does not slow or stall so that when you press the accelerator again, the blow off valve closes and the boost is there instantly because the compressor is still spinning fast.

A diesel engine doesn't have a throttle butterfly valve to restrict the inlet when you take your foot off the accelerator, so the turbo does not slow/stall anyway.
http://www.ds3club.co.uk/showthread.....6-hdi-110-bhp

[mjogreen]

Does anyone remember what we decided the noise coming from my turbo was? Did we decide it was blow off valve? That sounds stupid and I love it

[BenS]

Didn't know diesels don't have/need BOVs, learn something new every day I'm guessing Liam remapped though?

[Jd96ds3]

Awesome cheers guys��

[WTF]

Didn't know diesels don't have/need BOVs, learn something new every day I'm guessing Liam remapped though?

De cat and remap yep The NOS was the nail in the coffin......

Sent from my SM-G925F using Tapatalk

[Czar]

Wait, do you want turbo flutter or a blow off valve? BOV = buy a loud aftermarket one as the factory fitted ones are silent. Flutter = bypass your factory BOV. To be honest, the turbos in DS3s are so small and run such low boost pressures you probably won't hear much in either case unless you remap to a higher boost pressure.

Not quite BenS

Turbo flutter, I could go into a very lengthy technical explanation, as to exactly what turbo flutter (chat) is, and why it should be avoided at ALL costs, and NOT something to be proud of.

To keep it to the point, the flutter (chat) you often hear, is a culmination of the charge air pressure being trapped within the turbine compressor housing, from the instant closing of the throttle, when there is neither any internal recirculation valve or bleed off valve to atmosphere fitted, or indeed when the turbo working pressure has been increased and any bleed off, either internally or atmospheric, has not been installed or indeed matched to the now increased charged air pressure.

The trapped charge air pressure is now fighting for space, as the turbo is driven by the exhaust gases , the turbo is still trying to produce charge air pressure, with that trapped (throttle closed) charge air pressure, and the quickly increasing positive charge air pressure, confined in a very limited space, with nowhere to go, we get a very high internal pressure, which causes the turbine compressor wheel to slow at a very high rate of speed, of which it was not designed for, remember, these wheels spin way in excess of 100,000 RPM, and in the case of the petrol THP (turbo high pressure) there's a clue there BenS, more on that in a minute, when under full working charge pressure, spin in excess of 200,000 RPM, and you hopefully, can now see, that upon closing the throttle, with nowhere for the charge pressure to bleed off, this very high pressure factor of trapped charge air pressure is now acting on the turbine compressor wheel, to stall it, whilst at the other end of the impeller shaft, the exhaust gases are still driving the turbo, producing, or trying to produce charge air pressure, with the charge air pressure with nowhere to go.

We now have unequal forces acting on the exhaust turbine wheel, the compressor wheel, the impeller shaft and the shaft support bearings, all these unequal loadings are trying to separate the exhaust turbine wheel from the compressor wheel along the impeller shaft, trying to twist it to the point of malfunction, and this is good thing, you might think differently, after understanding this !!

The charge air pressure surge acting upon the turbine compressor wheel, with nowhere to go, starts to vibrate, the vibrations produce harmonics, the vibrations are also subject to heat, and the more we squeeze the air, the greater the heat, the greater the vibration, the louder the heat harmonic vibrations, commonly known as turbo flutter (chat) this acoustic phenomena, is when we encounter supersonic air speed, with a stalling reverse pressure, the two extreme differential air pressures, separate from one another, as the heat harmonic vibration pressure wave frequencies collide, this separation collision is the acoustics you hear as flutter (chat)

NOT such a cool or good thing after all.

Back to THP BenS, as I mentioned earlier, THP (turbo high pressure) the turbo is small, for one very good reason, very quick spool up response from 1,600 RPM, the turbo is producing effective charge air pressure, as for low boost, I guess you don't consider 0.9 bar (13psi) - 1.3 bar (18.8psi) to be high pressure, that's 13psi - 18.8psi (pounds per square inch) get your head around, per square inch, that is high volumetric pressure.

[BenS]

^ A much better explanation lol. TBH I thought the turbo only ran about 1.15 bar. I know that flutter is very bad for the working parts due to the pressure surge, but he just asked how to get it - which is by removing the relief valve. I also assumed that smaller turbos would amplify the sound less than for example a GTR turbo, but I don't know much about that.

Thanks for giving the full scientific reasoning! I'm a BOV fan anyway, gotta love the PSSHHT.