High pitch whistle! WTF

[LSKILLA]

Ok here we go, I installed the Boss intake Monday night. Tuesday on the way to work I heard a high pitch whistle coming from under the hood. So Last night I went and retorqued all the intake bolts and TB bolts, no issues. Now I only hear it from around 1500-2000 RPM. If I hold it at 1500 and gently press the gas I hear it, if i aggressively get on it nothing. I dont get it. Sounds almost like a belt slipping. Car is 2013 with 3k miles. Has anyone else heard of this?

 

[manolith]

Ok here we go, I installed the Boss intake Monday night. Tuesday on the way to work I heard a high pitch whistle coming from under the hood. So Last night I went and retorqued all the intake bolts and TB bolts, no issues. Now I only hear it from around 1500-2000 RPM. If I hold it at 1500 and gently press the gas I hear it, if i aggressively get on it nothing. I dont get it. Sounds almost like a belt slipping. Car is 2013 with 3k miles. Has anyone else heard of this?

is normal. i can stil hear it now with the blower.

 

[burke985]

could be your CAI you are hearing a little more pronounced now

 

[LSKILLA]

Well I had a buddy tell me that he heard something similar and now he is used to it and doesn't hear it. I just dont know if I can overlook it. Its loud! I can hear it over the exhaust and radio. Thought about pulling it off and changing the intake gaskets. Is that a waste of time and money?

 

[Chaney5.0]

It's a more pronounced intake. Flows better, so you are going to hear the wind being sucked in and it is causing a whistle. I am guessing you deleted the idiot tube?

 

[2012csgt]

Did you port or grind away the "teeth" in the opening of the throttle body, if so, that would make it whistle.

 

[Need4Speed03]

Mine don't make any noise, I think you have a vaccume leak. Id pull it off and check the gaskets...also double check all the injector o-rings.

 

[LSKILLA]

Idiot tube delete and no porting or grinding. If it is a vacuum leak would it throw a code? And why wouldn't it get louder the more I masshed the gas?

 

[manolith]

I am 100% sure that he does not have any leaks. It seems that this happens after the throttle body is flipped with the boss intake. I think that the whistle is the air rushing by the throttle blade at part throttle. Maybe with an aftermarket bigger throttle body it does not cause the whistle because the air slows down a bit. Maybe that's the only good reason to spend money on a tb for this cars.

 

[sloppymax]

I have the stock manifold but 85mm tb and airaid with the insert in currently. I get the same whistle under the same conditions. Double checked everything and no leaks. No drivibility issues to speak of and a solid idle.

 

[Bluebolt]

I have a whistle in mine at the same rpm range and its bone stock under the hood. I do still have the "sound tube" though.

 

[turbosha]

Idiot tube delete and no porting or grinding. If it is a vacuum leak would it throw a code? And why wouldn't it get louder the more I masshed the gas?

The more you mash the gas the less vacuum pressure you have on the engine side of the tb. I have a boost/vacuum gauge but no supercharger.at wide open throttle the vac is at 0. At idle or decell in gear it goes to -30 vac. So the more you mash the gas the sounds goes away?

 

[5PNTSLW]

what CAI? I have a slight noise from the intake in the low RPM(1500-2000), but you don't hear it after that, especially not over the motor,exhaust, and radio. Mods in sig, stock TB

 

[LSKILLA]

Turbosha, Thanks for the info. I dont know why I didnt snap to that.
5PNTSLW, Im running a JLT

 

[Need4Speed03]

Idiot tube delete and no porting or grinding. If it is a vacuum leak would it throw a code? And why wouldn't it get louder the more I masshed the gas?

No, it wouldn't throw a code if it was a minor leak at rpms above idle. You said you retorqued the intake and TB bolts and it got better? That to me would indicate a possible leak. And yes you wouldn't necessarily hear it the more you mashed the gas. An cut or split injector oring could cause that also.

I mean its possible you don't have a leak but if its as loud as you say it is, then its very possible you do.

 

[Need4Speed03]

I am 100% sure that he does not have any leaks. It seems that this happens after the throttle body is flipped with the boss intake. I think that the whistle is the air rushing by the throttle blade at part throttle. Maybe with an aftermarket bigger throttle body it does not cause the whistle because the air slows down a bit. Maybe that's the only good reason to spend money on a tb for this cars.

How can you be 100% sure? Does the OP have a supercharger? If not then the TB does not need to be flipped with the Boss IM?

 

[LSKILLA]

I didnt retorque, sorry, I just checked the torque and it was good 85 in/lbs. No adjustment made. My car is non supercharged. One thing is what do you mean the TB needs to be flipped? I put it on just how it came off. Is that correct?

 

[Need4Speed03]

I didnt retorque, sorry, I just checked the torque and it was good 85 in/lbs. No adjustment made. My car is non supercharged. One thing is what do you mean the TB needs to be flipped? I put it on just how it came off. Is that correct?

On a N/A application the TB goes on the Boss IM just like the stock intake, you did it right. Some people give comments or advice and they don't know what the heck they are saying! With a Paxton/Vortech the TB needs to be clocked to provide clearance for the supercharger.

 

[LSKILLA]

Ok I got you. Well I talked to a buddy and he told me to use propane to check for the suspected vacuum leak. Guess I will try that tonight when I get home. I will keep you guys posted. Thanks for all the help

 

[manolith]

No the intake does not have to be flipped. It was a really long time that I did mine. Anyways I don't know what I am talking about but I have driven 3 cars with the boss intake manifold and they all have the whistle at part throttle. They must all have vacum leaks.