Hi All

I have a MY02 STI which makes a flujtter sound on high boost. Not sure what is causing the problem if any.

The car is stock apart from TB exhaust and pod filter. The car spikes around 1.5 bar which i feel is too high - but when it spikes on occasion it makes a fluttering sound and you can see the boost gauge needle bouncing around the 1.5 bar mark. Then after a sec or two at the boost it hold firms around 1.2 bar. I noticed this a little while after a purchased the car and thought it was the HKS SSQ bloff valve not holding the boost - i have since put the stock blow off valve back on.

I really need to get the car to ASG to do a tune - just need to save up the cash.

Can anyone explain what is happening.


Anthony

Compressor surge. Not good for the longevity if the turbo.

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RS Liberty - Because WRX's are only good for parts...

http://www.streetfire.net/video/true...rge_163406.htm

Just sounds wrong when it happens.

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What is required to fix it ????

Anthony

A reduction of boost or a bigger turbo.

Compressor surge will kill your engine & turbo.



Eliminate your lack of boost control (you should NEVER see a .3 bar spike EVER) otherwise you risk popping something.

Has this car been verso'd?
Does it run any non standard boost controller (i.e a boost Tee)?
Is the boost control plumbing correct?


Until you have it looked at, avoid the spiking by lifting off a little as it builds boost.

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Rossco

Car is running stock boost control.

I asked the question before about the spike and was informed was normal, however a tune was recommened.

http://www.perth-wrx.com/vb/mechanicals/33737-my02-sti-boost-spike.html

The car has not been verso - i guess if i get a tune done the spiking will disappear aswell as the fluttering sound

Anthony

replace boost control solenoid at the time of getting verso done.

use something like a grimspeed boost control solenoid

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Mine is Verso'd with a 34 and mine makes a similar noise when at low rpm and planting it in 4th. Apprently it's normal? Doesn't seem to effect the performance of the car, still feels normal as it comes on boost - Doesn't shudder or stutter at all.

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I fail to see how compressor surge as the above vids would kill engine and turbos

compressor surge is what happens when you dont run a bov and the air gets forced back through the turbo rather than venting via the bov

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M POWER

A BOV prevents compressor surge on shifts. You can get surge at lower rpm when you make too much boost too early. Usually you need to be in 4th or higher to build enough boost that early.

This can be tuned out easily. Just need to lower the target boost and WGDC values at the rpms where the turbo surges. If you requested this specifically it can be done in a verso tune.

If you log manifold pressure during surge it looks like a saw tooth as it spikes up and down and then flattens out once the engine starts to flow a bit more.

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