Wastegate flutter isn't bad, the noise can be annoying however. As long as you're hitting your target boost, you're fine. Try wrapping your downpipe, that helps muffle some of the flutter noise.

Now, if that fluttering you're hearing is actually compressor surge, then yes, you have a problem. Typically wastegate flutter sounds almost like cricket chirping, if that's not what you're hearing, you might be experiencing compressor surge, which is really really bad for your turbo. At lot of times this will happen if you have an aftermarket BOV that is adjusted too tightly.

 

thanks for the reply. It sounds like soft fluttering of wings. It only occurs for a few seconds when i get on the gas at 4/5th gears.

 

That sounds more like compressor surge than wastegate flutter.
Are you running an aftermarket BOV?

 

i used to get that with my car, i preloaded the wastegate and it went away. and i get more boost with the newer accessport map, and spool is much better. car runs beautifully.

 

yeah just adjust your wastegate actuator arm, do a search you'll find plenty of answers, just about everyone has this prob. when they run a aftermarket dp (bellemouth more often than not)

 

no, i don't run aftermarket BOV. I also notice a very high-pitch whistling sound. Is this the turbo whistle? But then there's also a lower toned whistling if I get on the gas pedal.

 

no, i don't run aftermarket BOV. I also notice a very high-pitch whistling sound. Is this the turbo whistle? But then there's also a lower toned whistling if I get on the gas pedal.

Uh Oh, I think the fluttering you have been hearing is compressor surge, and that low pitch whine you hear is what is known as "turbo whine" and usually happens before your turbo goes bye bye.
Compressor surge can destroy your turbo if you don't take measure to get rid of it ASAP. But it sounds like the damage might already be done if you are hearing the turbo "whine" and not just the "whistle".
Does your boost ALWAYS come on strong? Or are there sometimes that you have to let off the gas and then get on it again to get into boost?

 

What?! :confused1 :eek3:
the boost comes on strong all the time. there's no spiking issues at all. The PSI readout from AP has been right on the money with what Cobb stated. Stage I I got ~14.5 in 4th/5th pulls and now Stage II it reads 15.7psi on those pulls.

 

What?! :confused1 :eek3:
the boost comes on strong all the time. there's no spiking issues at all. The PSI readout from AP has been right on the money with what Cobb stated. Stage I I got ~14.5 in 4th/5th pulls and now Stage II it reads 15.7psi on those pulls.

Sorry,
I am not trying to scare you. I just want you to know any possible problem that MAY be.

Try to adjust the wastegate as the others have said and see if it solves your problem. Hopefully it will get rid of the fluttering sound, then you will know if it was compressor surge or wastegate flutter. If you still get the sound, along with the "low pitch whistle" it is probably compressor surge, and possibly turbo whine.
Usually surge happens when a turbo is out of its efficiency range, or as stated above, your BOV is too tightly sprung. I don't have any compressor maps to look at for the stock turbo, so I can't really tell you if you are in/out of your efficiency range.

 

If you say when you get on the gas that for a little bit you hear the fluttering, then I had that same problem with my old stock turbo. That turbo was burning oil bad out the exhaust and it was making that noise so I decided to replace it. When I yanked it out and checked the shaft play, it was not that great. Probably the cause for making that brief fluttering until the blades got up to a high speed. My new turbo doesn't make that fluttering.

 

uh..... i wouldnt freak out just yet. i think there are people on here taking guesses but i personally dont agree with them.
if its makeing a surging noise when you get OFF the gas, thats compressor surge and could be a bad thing. however i am almost positive this is not what you are experiencing.
if its making a whispy sound when you're ON the gas, especially at partial throttle and/or low boost building up, thats just wastegate flutter and is perfectly normal. its part of what makes my car what it is so i embrace it personally and enjoy it along with my turbo whistle sound (which doesnt mean my turbo is on the way out either, haha).
ugh... misinformation is a biotch so hopefully this helps.
bryan

 

uh..... i wouldnt freak out just yet. i think there are people on here taking guesses but i personally dont agree with them.
if its makeing a surging noise when you get OFF the gas, thats compressor surge and could be a bad thing. however i am almost positive this is not what you are experiencing.
if its making a whispy sound when you're ON the gas, especially at partial throttle and/or low boost building up, thats just wastegate flutter and is perfectly normal. its part of what makes my car what it is so i embrace it personally and enjoy it along with my turbo whistle sound (which doesnt mean my turbo is on the way out either, haha).
ugh... misinformation is a biotch so hopefully this helps.
bryan

Compressor surge does not always happen only upon releasing the gas. It can happen if the turbo is going bad, and/or it is being pushed beyond its efficiency range where boost patterns become unstable.
As far as the whispy sound....in his original post he said he heard the high pitch "whistle" from the turbo, But ALSO heard a Low pitch Whistle, which I liken to turbo whine.

Just keep an eye out to see if you are burning oil, or if the "low pitch whistle" gets deeper and more noticeable. It will eventually sound like your turbo is crying in pain if it is turbo whine. If nothing changes after a few hundred miles, than it is probably wastegate flutter like wrinkleboi says.

P.S. I am just trying to help you possibly avoid catastrophe. My rx7 with stock twins started whining and I didn't do anything about it at first, and then BAM, my compressor wheel on the #1 turbo jammed into the compressor housing and my car almost lost all of its oil through the turbo bearings in about 5-10 seconds. Luckily I cut the car off in time so I didn't damage my fresh PFR rebuild. So again, I am just trying to help you avoid much further damage than just a turbo.

 

thanks for all the replies. So far oil consumption has not been an issue. In fact I've never noticed any significant oil consumption at all from day 1.
The low pitch sound has been around since Stage 1 days which was like 2 months ago. The high-pitch whistle is heard now because of the dp installed.

 

thanks for all the replies. So far oil consumption has not been an issue. In fact I've never noticed any significant oil consumption at all from day 1.
The low pitch sound has been around since Stage 1 days which was like 2 months ago. The high-pitch whistle is heard now because of the dp installed.

You should be good then.
It is hard for people to diagnose problems via the internet and words. If I had the car here I could tell you a lot more about what you are hearing. But one persons description of a whistle, might be anothers of a whine.
Anyway, this post has some good info from some obviously experienced people, I would take all of it into account and then make your own educated decision on possible problems/fixes. I would start with the easiest solution first (ie wastegate arm adjustment) and then work from there. Or you could go by the rx7 montra....if it ain't broke, it will be soon enough, so fix it then.
Peace

 

Related note...

I am having a weird knocking sound when I let off the gas and it goes back to idle. I thought it might be rocker knock, but when I took it to the dealer the service manager and I both noticed that it is coming from behind the engine... could be the turbo or something. Now could this be the wastegate, or is it a busted fin, or worse off is there mad shaft play in the turbine? And might this be fixable? Thanks

Oh and it will do it at idle after a spirited run....

 

the whistling noise is normal, mines really loud, and this is my second turbo, first one i lost the oil seal and it was smoking like crazy, they both sounded identical, i picked up the new one w/ 5k on it so i'm pretty sure there's nothing wrong with it

 

Well, how about

I don't notice any unusual sounds, but when I'm going wot passing on 2 lane highways (about 70-90?) it feels like the boost is cutting out intermittantly, and I can see the boost gauge bounce around a little. I'm stock except for an MRT turbo back and running Cobb Stage II.
Anyone experienced this/ know how to fix it?
Thanks!

 

is there any way to get rid of the vf34 flutter? it's not so bad, but i wouldn't mind not hearing it

 

I used to get the same noise on my stock turbo, i wraped the downpipe and you could barely hear it, then installed a GM boost solenoid and it is totaly gone and boost is much easier to control.

If you use a UTEC i recomend the GM boost solenoid as a great 30$ mod

luke

 

Wrapping the downpipe made that much a difference? That's very interesting. Sometimes I hear the clanking and t-t-t-t stuff from my stock setup and sometimes I don't, but I admit when I do I have to remind myself it's the gate and not something bad going on. Does it at odd times too sometimes, depending on load etc., catches me by surprise.

That GM solenoid is really popular with UTEC folks, good to hear you like it.