# Turbo Blowoff Flutter



## JLL (Sep 12, 2017)

Turbo flutter means that the boost pressure is going backwards through the turbo instead of being blown off or recirculated.


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## voided935 (11 mo ago)

JLL said:


> Turbo flutter means that the boost pressure is going backwards through the turbo instead of being blown off or recirculated.


I figured that's what it is which is why it flutters and sounds choppy, do you by chance have any fixes for it?


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## JLL (Sep 12, 2017)

voided935 said:


> I figured that's what it is which is why it flutters and sounds choppy, do you by chance have any fixes for it?


Turbo flutter is normally caused by a malfunctioning bypass or blow-off valve. Or a bypass or blow-off control issue.


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## Dave's World (Feb 4, 2021)

I've tested the turbo a few times. I have also tested some of the valves you can get on the market. I have a video showing results BUT how many miles are on your electronic part of your valve? Not the upgraded half?


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## Mothman (8 mo ago)

I'm pretty much in the exact same situation. Same mods as of right now except for the throttle spacer and magnaflow exhaust. The fluttering started as soon as I installed the HPRV. I'm still making full boost (21.5 psi) and not going over. So the wastegate has to be opening at some point to stop me from running too much boost. However, no matter how much boost pressure or rpm I'm at, it still flutters when letting off the gas. The only time it doesn't flutter is for like the 2-3 minutes right after a cold start before anything warms up. I disassembled the whole thing and both the wastegate actuator and the control arm move properly on their own. The only thing I can think of is that I might have a boost leak somewhere, but I still need to test it. What is confusing me is that I'm still hitting the right boost pressure, so it is opening at some point, but when I let off the gas it flutters meaning it isn't opening. Also, I am running the proper tune for the HPRV.


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## Dave's World (Feb 4, 2021)

Mothman said:


> I'm pretty much in the exact same situation. Same mods as of right now except for the throttle spacer and magnaflow exhaust. The fluttering started as soon as I installed the HPRV. I'm still making full boost (21.5 psi) and not going over. So the wastegate has to be opening at some point to stop me from running too much boost. However, no matter how much boost pressure or rpm I'm at, it still flutters when letting off the gas. The only time it doesn't flutter is for like the 2-3 minutes right after a cold start before anything warms up. I disassembled the whole thing and both the wastegate actuator and the control arm move properly on their own. The only thing I can think of is that I might have a boost leak somewhere, but I still need to test it. What is confusing me is that I'm still hitting the right boost pressure, so it is opening at some point, but when I let off the gas it flutters meaning it isn't opening. Also, I am running the proper tune for the HPRV.


The wastegate runs off boost pressure. So based on how much pre-load you give the wastegate it actually changes when it opens. You’re hearing a flutter because your diverter is not opening properly. Diverter is the HPRV. The HP RV does not change the diverter. It just changes the mechanical part of the diverter. Your diverters electronic part could be lazy or actually not opening as much as it should. Do you have a big turbo? Also if you want a little more boost you have to let me know how much preload you’re running and I can help you adjust from there.


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## Mothman (8 mo ago)

Dave's World said:


> The wastegate runs off boost pressure. So based on how much pre-load you give the wastegate it actually changes when it opens. You’re hearing a flutter because your diverter is not opening properly. Diverter is the HPRV. The HP RV does not change the diverter. It just changes the mechanical part of the diverter. Your diverters electronic part could be lazy or actually not opening as much as it should. Do you have a big turbo? Also if you want a little more boost you have to let me know how much preload you’re running and I can help you adjust from there.


Thank you for the response, I really appreciate it. I've definitely been eyeing that oil catch can kit on your shop for a bit lol.

But anyways, I have the stock turbo as of currently. Is there any way to test the electronic part to my diverter valve? Also, I have no clue how much preload I'm running. I'm still running the stock wastegate actuator.


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## Dave's World (Feb 4, 2021)

If you have the stock wastegate than preload is set by the factory. The problem is I have tested a ton of those and they get weak by about 20,000 miles. They open as low as 3 psi. What this means is the car gets limited on its power because it struggles to produce boost. On the flip side the diverter is designed to relieve that boost when it is created. If its getting lazy which does happen you start getting a flutter.


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## Mothman (8 mo ago)

Is there any way to test the electronics/wiring to the diverter valve? I took out the valve and it moves freely under spring pressure, so I am assuming it is the electronics. It builds and holds boost just fine, and it doesn't make too much boost, it just doesn't open when I let off the throttle.


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## Dave's World (Feb 4, 2021)

Not without a specialty tool. It’s just cheaper to get a new one.


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## Mothman (8 mo ago)

So I'm taking apart my intake right now to get to the diverter valve and inspect it, and I noticed more oil in my intake again even though I just cleaned it out recently. Guess my PCV valve is going to. I'm throwing any codes though which is weird. I'm only finding info on the gen 1 PCV valves, not much on gen 2.

Anyways, the wiring looks intact to my untrained eye, so I'm thinking it's the solenoid that is bad. I also found one post that said it could also be the secondary air injection bypass valve, but I'm not knowledgeable enough to know.


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## Dave's World (Feb 4, 2021)

No that is normal for the Gen 2. Check this video out it will make more sense on this situation.


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