SpeedI2acerX

iTrader: (2)

would getting a whole new bov completely solve the problem? yeah im surprise not everybody is having this problem. well not everybody have a boost gauge and a cai intake. also with the oem intake and drop you cant hear it. ill try making that bov hose shorter.

Hiboost

iTrader: (9)

I put a cap over the T leading towards the BOV and also another cap on the end of the BOV itself. I knew it would be compressor surge city so I took it easy totally off boost. Got on the throttle in 3rd gear and it only hit 18 PSI max boost. The boost gauge needle was pretty steady but it was like that at lower boost already.

Does this mean it only holds 18 PSI without the signal boost helping keep the valve sealed?

My next test was taking the stock boost solenoids totally out of the loop and placing the boost gauge on the Turbo outlet leaving the BOV with a dedicated tap to the intake manifold again. The boost is rock steady at full throttle but now I only drop to 1 PSI when coasting and it actually hovers at 5 PSI while cruising which is totally bizarre. I guess with the turbo always spinning we get some pressure in the intake pipes even if the engine is under vacuum in the intake manifold.

I guess my next test is to use a T in the fuel pressure regulator boost hose on the intake manifold and put the boost gauge source there.

Hiboost

iTrader: (9)

Update time and resolution!

I finally got my boost gauge to stop fluttering like mad at mid to high RPM, it never did it at low RPM even at 26 PSI which stumped me. Turns out taking the signal off the BOV is really turbulent and at different RPM's it will cause pressure waves to cause the needle to flutter. Not sure if my BOV signal line is also leaking at higher RPM's but the inability to read the gauge was a headache.

I tried restricters in the line right off the T as well as just before the gauge but they only helped slightly since there was already a smaller restricter hole right inside the gauge that was doing the same thing. I ended up getting a proper sized 3/8"<->1/4"<->3/8" T to tap into the brake booster line which was huge, but it was halfway down the intake manifold far, far away from the throttle body and BOV. Now I have perfectly accurate readings on my boost gauge again, perhaps down the road I'll look at how replacing the BOV effected the jumpy needle. I'm pretty sure it's not compressor surge at this point though so I'm not making it a major priority.

For the search engines: Boost Gauge Flutter Fluttering Bouncing Vibrating Needle

SpeedI2acerX

iTrader: (2)

so your fluttering was coming from the boost gauge line?glad you fix the problem but mine was happening before i added the boost gauge. before the gauge it would give that fluttering sound at mid rpm when i stomp it. i still get the problem here and there. had pete from Works take a look at it but he couldnt find anything wrong.

Hiboost

iTrader: (9)

Nope, same line was used at different tap locations:

Tap off driver's side of Intake Manifold at BOV signal line = 2-3 psi Gauge Flutter

Tap off Turbo Outlet at MBC signal line = no vacuum but almost zero flutter

Tap off middle of Intake Manifold at brake booster source = almost zero flutter

Basically the air seems to be turbulent leading into the BOV signal line and there is definitely some kind of leak or pressure wave bouncing around in there that the gauge is picking up. If you are hearing a flutter at mid RPM when you stomp on it you very well could have a leak, my guess is the BOV doesn't always seat which would make it intermittant. You could also do some leak tests at 20 - 25 PSI and see where the major holes are.

Try and swap someone elses BOV in, preferably different from stock and see if the problem goes away. I'm likely going to replace mine to see if that flutter is gone or reduced as really I'm just masking the problem by avoiding tapping the gauge near the throttle body. There is still some crazy turbulance and pressure waves bouncing around that area that my gauge was reading.

CoEVOX

I'm a bit late to the conversation, but I've been noticing a fluttering sound for the last couple of months coming from the engine bay at high rpms (5k - redline) and at full throttle while in 2nd & 3rd gear . Its a dull sound like: "duh duh duh duh duh duh". At first I thought it was just my turbo leaking pressure, but without any gauges I couldn't tell. Today, though, I tried just switching my air filter back to stock (only mod I have is HKS filter) in case there was something occuring due to the increased airflow at high rpms. I did a couple of runs and only barely heard the fluttering once. I've left the stock filter in there to see if it reoccurs over the next few weeks. I have a service coming up soon too so I'll have the dealer check everything else out.

edit: I've listened to the "compression/fluttering" examples on YouTube and it sounds nothing like that, more dull of a sound (almost a vibration) and quieter, plus it only occurs at full throttle not after I let off.

SpeedI2acerX

iTrader: (2)

^ yeah with the stocker on you wont hear anything. i started hearing mine after the aem was install. i hear its normal as long as its not compression surge.

DueceEVO

I also am getting this annoying flutter sound. HOw do i know if there is a leak?

philamthebest

iTrader: (4)

are you driving an MR or a GSR? As after my tune and putting a EBC you will experience a flutter, its got something to do with the air pressure contained from the EBC. Not sure a way around it yet, but i think when people can start tapping into the PILLS this will help.

AlexP

Phil how much hp and tq are you running?

DueceEVO

Mines a stock 08 GSR, I do hear the flutter but i dont have a boost gauge yet.

EvoDom

iTrader: (7)

turbo surge does occour while on the throttle, you could have a lil case of it when you get into high rpms. If not get rid of the BOV and try a JDM IX BOV or a stock evo IX bov, they hold well to about 24psi.

DueceEVO

my flutter happens low rpms when i let off throttle or sometimes i hear what sounds like the bov working correctly then it flutters towards the end of the sound.