Yes another compressor surge thread.

[wannabox]

I did search and read through some of the other ones but thought I would post my issues.

I have just had FMIC, Pod, Exhaust, HKS SSQV BOV and verso done. I notice that in say 3rd gear After around 3000rpm builing boost I will hear what I think to be compressor surge. It will die off up in the revs after around 4500rpm.

I also get the same comming off throttle at lower revs it will flutter for days. Now my main concern is is this bad? I plan on taking it to ASG when they get back but it would be good to get some advice for now.


Cheers

[Elrico]

Flutter indicates that there is pressure being pushed back into the turbo. Is the HKS SSQV brand new? It might be on a tight setting to plumb it back or be pushing air back into the turbo. My GFB hybrid is set to tight and does the same thing. At low revs, it flutters.

Dont know about the comp surge though.

[Evidencee]

Compressor surge while on throttle should sound the same as the sound you get when off throttle.

The sound your getting when coming off the throttle is flutter, caused by the bov not venting and forcing the air back into the spinning compressor blades of the turbo. Check the vacume line coming off the ssqv and make sure its not loose. The vacume nozzle on the ssqv's are pritty thin and the factory vacume hose is too big for it so make sure its on tight with a zip tie.

Flutter at low revs isnt too bad on your turbo, but if its still fluttering at full boost, it could very well damage your compressor wheel especially if your running high boost.

[Skipmaster J]

When ASG re-did my stock boost control it spiked to 1.7 bar before settling at 1.5 bar... Roughly when it hit peak torque you'd hear the compressor surge (full throttle, heavy load, high boost... probably not healthy for the turbo) - too much boost for the engine to use I'm guessing.

I've got an EVC that's due to go in to limit the boost to 1.5 bar and hopefully that'll stop the surge.

I was advised that the surge noise was normal by the guys at ASG but I'm not particularly sure about that... hence i bought the EVC

[RichX]

I'm stil waiting for tuna to come out with his technical explanation of compressor surge ..

[tuna]

Mister Two?

[Mister Two]

HAHA...

Mr Google to the rescue...

Put Simply, compressor surge happens when the turbo is pushing more air than the engine can ingest. Usually happens at low RPM when the turbo is spooling up. Its spools up too quickly and because of the low RPM, the engine cant ingest all the air so you get air moving back into the compressor housing making that sound.

To fix it you can...

Port the waste gate to improve flow through it to reduce turbine speed.
Bigger exhaust housing to slow turbo spool.
Improve flow into the combustion chamber - head work, cams, etc...

My brain hurts so feel free to refute Stace.

[RichX]

Originally Posted by Mister Two

HAHA...

Mr Google to the rescue...

Put Simply, compressor surge happens when the turbo is pushing more air than the engine can ingest. Usually happens at low RPM when the turbo is spooling up. Its spools up too quickly and because of the low RPM, the engine cant ingest all the air so you get air moving back into the compressor housing making that sound.

To fix it you can...

Port the waste gate to improve flow through it to reduce turbine speed.
Bigger exhaust housing to slow turbo spool.
Improve flow into the combustion chamber - head work, cams, etc...

My brain hurts so feel free to refute Stace.

Exactly as i said in the previous thread? But i was shunned by someone saying i had no idea what i was talking about.

[wannabox]

Cheers guys, guess thats what I get with stock turbo running 1.5 Bar. I will leave it let it blow and give me an excuse to get a td06.


Cheers

[Kato]

It's a fact of life. Ignore it.

Doubt it will do anything 'bad' to the turbo either.