Turbo Chatter

[Caspersmith]

Installed oversized Ram Air induction kit at the weekend & now getting seriously loud turbo chatter, petty much like the waste gate sound.

Does it under light & hard acceleration then let off.

Sent a video of it to my mate & he said I need to be careful as it might be surging which isn't good!

Done loads of reading,  some say mapped K04's appear to do this & shouldn't be an issue. Only had the car a month but think the car has been mapped as it feels quick.

Anybody else's motor do this?

Dan



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[slix]

Yeah I used to get the chatter when I had my ramair on my ed30.

[RetroRaz]

I get it if i build up boost, let go of throttle and then tap it again. Like the sound but i also read its not good for the turbo. Best not to do it I guess.

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[ROH ECHT]

Would be good to know if it is surge or DV venting. Can you give your boost's actual max psi? Have you a data log comparing target and actual? What is the diameter of the intake just installed? Do you have mass air data, in g/s, taken before and after the intake install? It is possible the MAF is reporting less air to the ECU than what is actually entering now.
It is possible the actuator has too much preload in relation to engine vacuum. You could reduce it and see if target boost is still reached, but if the surge is eliminated. Surge in our cars is usually due to already, or quickly, compressed air no longer flowing momentarily. The K04 is known to build boost quicker than most...so you could be better off taking 1mm or 1.5mm off of preload on the actuator rod. This will allow target boost to be achieved but will allow the WG to open sooner.

[Caspersmith]

Would be good to know if it is surge or DV venting. Can you give your boost's actual max psi? Have you a data log comparing target and actual? What is the diameter of the intake just installed? Do you have mass air data, in g/s, taken before and after the intake install? It is possible the MAF is reporting less air to the ECU than what is actually entering now.
It is possible the actuator has too much preload in relation to engine vacuum. You could reduce it and see if target boost is still reached, but if the surge is eliminated. Surge in our cars is usually due to already and quickly compressed air no longer flowing momentarily. The K04 is known to build boost quicker than most...so you could be better off taking 1mm or 1.5mm off of preload on the actuator rod. This will allow target boost to be achieved but will allow the WG to open sooner.

Thanks for the pointers, not done any of the above.

Looking at getting ODB Eleven soon so hopefully be able to read some information & see what boost levels are doing.

The intake kit is 90mm through to 70mm at MAF point.

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[ROH ECHT]

Well, that is an OK size not prone to cause issues with MAF readings. So yeah, look at the boost data to see if actual exceeds target by much and for how long. A 3rd gear run from 2k rpm to redline is good...so plan on reaching 90 mph for this = safety 1st! 
You may find the WG calibration for the k04 is just simply a bit much and all can be smoothed out reducing preload. I will be doing a vid soon showing how simple this is to do. You can find it here when completed on my youtube channel: https://www.youtube.com/user/zoomdis/videos