Wastegate Flutter

[Andy_Mac]

Spitballing ideas here. Not really a fan of the extreme wastegate flutter i'm getting currently, sure its alright at WOT but annoying when driving semi casually. Could putting a fairly large diameter restrictor pill in the wastegate vac line smooth out the 3-port solenoid pulses enough to reduce this or am I thinking about this in the wrong way. Think it'd be a bit of a ballancing act to get the size right so that it doesn't slow it down enough to cause boost spikes.

Tweaking the duty tables in the tune may help but not sure if thats a good way to get around the problem.

There's a poormans attempt at recording how she's sounding with low/medium throttle

Edited February 25, 2016 by Andy_Mac

[lachlan]

Similar effect to a ristrictor but easier to test is just make the hose to the actuator longer . Put half a meter or a metre coiled up and see if it achieves the desired result .

[Andy_Mac]

Ah yes. Good thinking, i'll give that a go tonight.

[Andy_Mac]

Lachlan wins this weeks e-points. Half a metre longer made all the difference.

[hunter951]

waste-gate flutter or turbo surge?

[Andy_Mac]

Definately flutter. Surge is more when coming off throttle. Was getting some surge too but sorted that out with the BPV adjuster.

[hunter951]

 Andy_Mac said:

Definately flutter. Surge is more when coming off throttle. Was getting some surge too but sorted that out with the BPV adjuster.

no not entirely true. my vf30 surges hard on full throttle until high rpm, and also surges coz bov is pretty tight of throttle.... what turbo are you running and boost?

Edited February 27, 2016 by hunter951

[Andy_Mac]

Yea was making more of a general comment.

You have a 3-port solenoid on yours? Pretty common to get flutter, just couldn't find any real solutions to it other than people adjusting wastegate actuator arm lengths.

In my case there was 2 very distinct noises happening at different times. Sorted them at different times too so can confirm which fix removed each noise. On throttle noise was solved with a longer vac hose which as expected smoothed out the solenoid pulses and the 2nd noise was solved by winding the BPV adjuster out further to stay open longer.

Turbo's just a cute little VF45 currently at 16-17psi

Edited February 27, 2016 by Andy_Mac

[hunter951]

 Andy_Mac said:

Yea was making more of a general comment.

You have a 3-port solenoid on yours? Pretty common to get flutter, just couldn't find any real solutions to it other than people adjusting wastegate actuator arm lengths.

In my case there was 2 very distinct noises happening at different times. Sorted them at different times too so can confirm which fix removed each noise. On throttle noise was solved with a longer vac hose which as expected smoothed out the solenoid pulses and the 2nd noise was solved by winding the BPV adjuster out further to stay open longer.

Turbo's just a cute little VF45 currently at 16-17psi

yea with external waste-gate plumbed in... 22psi. Dont forget if you only half throttle you'll promote the surge more than full throttle in some senses, definitly going up hills. also with my old ebc i could run low gain and as a result no surge/flutter, but i hated the lag. sounds like you've pretty much got it sorted... but all iv heard is vfs are all about it and only why to get rid of it is to go big turbo....

[Guest]

 hunter951 said:

yea with external waste-gate plumbed in... 22psi. Dont forget if you only half throttle you'll promote the surge more than full throttle in some senses, definitly going up hills. also with my old ebc i could run low gain and as a result no surge/flutter, but i hated the lag. sounds like you've pretty much got it sorted... but all iv heard is vfs are all about it and only why to get rid of it is to go big turbo....

You can tune it out just wind down duty cycle to bring it on later. You can induce surge on big turbos too its just easier in a vf when you lug it or low rpm up a hill on boost.