So as you know just had my ko4 replaced because it blew. Im running trifecta and hitting 23-24psi under wot. I noticed that at that range i hear a loud whistle almost as if I had someone whistling in my passenger seat. To clairfy i am not talking about the tsssssss from the turbo building pressure. This only happens at this boost range. Any ideas? All piping is stock. Thinking about asking to turn boost down. Dont wanna blow this turbo too

 

could possibly be a small boost leak. especially being on stock piping.

 

I have the whistle too. Its only noticeable above 18 psi. Ive had it since I tuned the car. Stock boost does not make the whistling noise your refering too. It scared my wife when she first heard it. She thought something was going to explode lol. I believe its normal.

 

Boost leak

 

I can't say one way or the other for sure. But my car makes the same whistle noise. I have checked for boost leaks. At fist I did have leaks around both sensors in the charge piping thanks to the gm dealer leaving the green seals on the sensors and not installing the proper seals. As of right now it still makes a whistle noise and if I have any boost leaks. I sure can't find it. And I have checked everywheres.

 

Just wanted to update yall. This whistle still terrifies me

 

Make a boost leak tester

 

It's a boost leak, the reason the one guy got it when he was tuned is because the leak only happens at pressure over stock boost, fix ur couplers and tighten properly if not. And to op, turn ur boos down to 22 if u wanna be safe with the turbo. After 22,23 the turbo does nothing but make hot air

 

My car has always made a high pitched whistle above 20psi. It's just how the K04 sounds at high turbine speed. It did it all the way from being GMS1 (21-22psi) with just an intake at 26,000 miles and I've had apart the entire intake from the turbo to the throttle body to upgrade my FMIC and chargepipes and it has never changed. I have almost 70k on it now and it has been pushing 25psi since about 40k. Still sounds and performs the same.

 

Here, listen at the start of the 2nd gear pull in this video:


If that's what you hear, it's just how the K04 sounds at high boost.

 

I never noticed it on GMS1 but when I tuned trifecta I heard it for for first time going WOT. It was a good sound so I thought no worries.

 

I cant tell from the vid. But mine sounds just like someone is whistling loud as hell in my passenger seat

 

My k04 makes a different sound, depending on weather outside it sounds different. Sometimes it's there sometimes just sounds like normal turbo

 

o well. Ive got 12k mi and 12 months for something to go wrong

 

My Car makes the exact same sound as the video you posted. It is from what I have always understood, normal.

 

if everyones car makes it.... maybe its normal

 

So now that Ive actually taken a closer listen to that video. That does sound like it when you first get on it before the revs are up in the range. That's weird. I didn't get that on the turbo that blew. I cant recall ever having that noise on the old turbo in the 85k It was installed. Then again, ive only been tuned for 2k miles.

 

same. The video isnt doing it the full justice cause that video is recorded outside the car but the sound is alot louder than that. Its the same sound and I believe its normal on a cobalt pushing 20+ psi.

 

It may be a boost leak because i put an intercooler on my car and under any load it whistles. It will be worth making a tester and looking for a leak

 

Coming from experience, My first LNF ( now swapped to LDK ) I discovered injector seals with e85 being not compatible , one of the first things my car did was make a whistle at high boost. ( then eventually sounded like a Subaru ) I replaced the injector because the vibration from the squeal fucked it up in my opinion . If its not a boost leak, its the injector seal breaking down letting air escape creating that nasty squeal. I bet 9 out of ten cars with the squeal , take out injectors replace with better seals or just simply new ones and it goes away car will run better. I am about to do the same, My cars got the squeal and it pisses me off.

 

Good luck with your injector swapping. I do not believe that injector seals are going to fix it. When the combustion seal fails, which one of mine did at about 53k miles, the noise it makes is a knocking/popping noise under boost. I replaced the entire rail and all 4 injectors with a brand new assembly I bought from Mongorat on here. Came with the E85 black seals on it already. It's been installed since 53k miles and I have almost 70k now. Noise never changed when I installed the new parts.

Plus, think about it -- the whistle noise is VERY consistent, however the cylinder pressure in each cylinder changes depending on what stroke the cylinder is on, so I don't think that air escaping from past the combustion seal on the injector would create a high-pitched squeal noise.

Just my 2 cents.

 

I run 94 with 10 % ethonal , should I get the black seals or am I good

 

You only need the black seals if you're running E.

 

Thats weird , I replaced mine and it stopped, had engine swapped to LDK factory warranty and its back , factory installed injector rail Im guessing. You are telling the guy who wrote the original article about injector seal problem. so good luck to you as well. My guess is its something to do with the intake mani / rail area. somewhere in there is a high pitch squeal. Weather its boost leaking , vacuum manifold pressure etc , thats where the leaks at.

 

I dont get how this didnt happen on my old turbo but now it is happening