Whistle around -3 vacuum (video)

[ErikTande]

When I'm driving I get an annoying whistle around -3 vacuum. The turbo boosts fine, it goes away once I hit 1 psi or more, and it goes away at less than -3 vacuum.

I boost leak test to 28psi, no leaks. But then again, it's only happening in vacuum, so that's not helping me find the noise.

I changed the BOV (stock 1g to 1g dodge mod) and there was no change. Whistle is still there, so I don't think it's the BOV.

I changed the turbo, problem is still there.

I've checked over the intake multiple times, snugged things down, problem still persists.

I can't figure out what it is, and I can't figure out how to find the problem, since revving the engine when it's parked doesn't replicate the problem, I need to be moving. Any ideas on what it might be?

I'm guessing I'm going to have to pay to put the car on a dyno so I can find where the noise is coming from.

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[Dxc545]

So it's happening just when you start to get into boost? I'd check the turbo for play. Had a turbo do the same. It would whistle going into boost then fade.

 

[ErikTande]

So it's happening just when you start to get into boost? I'd check the turbo for play. Had a turbo do the same. It would whistle going into boost then fade.

No shaft play on the turbo. I've even switched turbos and the problem is the same.

 

[lil corb]

It kind of sounds like drivetrain noise? Is only by vacuum or by a certain speed as well?

 

[ErikTande]

It kind of sounds like drivetrain noise? Is only by vacuum or by a certain speed as well?

Only by vacuum, speed doesn't matter.

 

[biglady112]

It is the bov. It is an inherent problem with the 1g bov Erik. I just finished building this galant and reused the 1g bov. It does the same thing until you hit the brakes or touch the gas again. You just would not notice it on a returned setup usually. This car is speed density and it is very clear as it is vented. This car is going to California next week likely and if you want to come and compare you can before I ship it off to my friend.

I just watched the video and my phone does not make it sound that good. I maybe be wrong now having watched it. This galant does have a true whistle though coasting in gear from the bov. Not the first cat I have seen do it. You can always stop by and I can take a look.

 

[crimsondragon]

It actually sounds kinda cool. Like it's powering up or something. What throttle body are you running?

 

[Nuzzi]

Any possibility of a bad pulley or belt? oil pump? I had a similar noise, changed the alternator, water pump and timing pulleys before it went away.