Faint whistling noise when stabbing throttle

[whatisgrip]

Hello. Hoping someone can help me diagnose this mildly annoying issue that I've been having.

When stabbing the throttle around 2.5k-3k rpms I'm hearing a faint whistling noise from the engine. If I gradually increase throttle there is no noise. Sounds like it happens when the throttle body is opening. I've checked around for any vacuum leaks but all looks fine to me. Engine is stock, intake is enclosed with a custom lid and car has gt4 louvers so any engine noises will be exaggerated. No check engine lights and A/F ratio seems normal.

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[Chhris]

Hello. Hoping someone can help me diagnose this mildly annoying issue that I've been having.

When stabbing the throttle around 2.5k-3k rpms I'm hearing a faint whistling noise from the engine. If I gradually increase throttle there is no noise. Sounds like it happens when the throttle body is opening. I've checked around for any vacuum leaks but all looks fine to me. Engine is stock, intake is enclosed with a custom lid and car has gt4 louvers so any engine noises will be exaggerated. No check engine lights and A/F ratio seems normal.

I have a JLT open intake and when i stab in the throttle the whistle is pretty loud, after 4k rpms the exhaust becomes louder than the whistle so is harder to hear, thats probably what you hear, try opening the intake and see if the whistle gets louder

 

[Hobdul]

@whatisgrip I have this same issue. I think I started noticing it after doing two of the same mods as you: my mechanic installed full set of Trackspec hood vents and a custom airbox cover to seal it (now that the hood above it is vented). I will update the thread with any info on mitigating it after I talk to my mechanic. Thanks for starting this thread!

 

[matthewr87]

What sort of sharp implement are you using to stab the throttle? I usually just press it with my foot. No whistling noise.

 

[Vertex]

I don't have a 350, but on my Mach 1 after I replaced the stock engine air filter with a steeda one I did notice a whining/whistling noise that I presumed to be coming from better air flow like other have mentioned in here.

Not to say this is what you are in fact hearing

 

[Hobdul]

What sort of sharp implement are you using to stab the throttle? I usually just press it with my foot. No whistling noise.

Personally, I use a T-1000 liquid metal sword arm--find it gets me the best acceleration, but I do have to replace the pedals fairly often due to damage from the stabbing.

 

[MiamiGT350]

I'd try removing the air intake and see if you can still hear the whistling.

 

[mephim]

It’s the throttle body, you just didn’t hear it before. I’ve had both a 2016 and 2019 that both exhibit this once I move to the larger element filter (FP blue one).
I noticed it not being present at my first Track Attack in 2016. I took my first car to the dealer at the time and was told it was present on a lot of the larger TB mustangs.
I always just imagined there was some intake resonance at that speed, but it could be some weird boundary layer/laminar flow reaction.

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