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Discussion Starter · #1 ·
When I accelerate hard under load, I hear a high pitched whistle that sounds like either a blow-off valve, squeaky pulley or belt. It's only under heavy load/ at higher engine RPM. This is a separate a distinct sound from the super charger spooling up. It's bearable, but detracts from an otherwise excellent sound profile of exhaust and super charger whine (which I don't mind). Anyone else experiencing this?
 

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When I accelerate hard under load, I hear a high pitched whistle that sounds like either a blow-off valve, squeaky pulley or belt. It's only under heavy load/ at higher engine RPM. This is a separate a distinct sound from the super charger spooling up. It's bearable, but detracts from an otherwise excellent sound profile of exhaust and super charger whine (which I don't mind). Anyone else experiencing this?
Yes.

In my case it is just ignition noise coming through the radio.

It took me a while to identify it. It's been many years since the last time I heard that sound, and my ears have grown old in the meantime. :confused:

I have had a passenger hear that sound and mistake it for a turbocharger, so I don't feel so bad about it.
 

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Does anyone know how to fix this problem?
 

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Discussion Starter · #4 ·
Yes.

In my case it is just ignition noise coming through the radio.

It took me a while to identify it. It's been many years since the last time I heard that sound, and my ears have grown old in the meantime. :confused:

I have had a passenger hear that sound and mistake it for a turbocharger, so I don't feel so bad about it.
I don't think ignition is my issue. It's towards the end of the acceleration cycle, while approaching redline. I can hear the supercharger whine separately. It's sort of like a crescendo when engine noise reaches its peak. Interestingly, it's simply "turns on" and the pitch doesn't change. It subsides when I back off the throttle.
 

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Did you happen to custom-fit a Radium intake (or other) on your S? Some aftermarket intakes have been known to "whistle" at certain acceleration levels.
 

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Discussion Starter · #6 ·
Bone stock. I was thinking possibly something to do with the airbox, but I would expect the pitch to change as the acceleration increases, which it doesn't. That is why I originally speculated it was some sort of controlled release of pressure.
 

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Bone stock. I was thinking possibly something to do with the airbox, but I would expect the pitch to change as the acceleration increases, which it doesn't. That is why I originally speculated it was some sort of controlled release of pressure.
I'd be surprised to hear that noise on a stock car. However when intakes do this, it's often not related to rpm at all. Its a factor of airflow passing through the intake valves at a certain rate. For instance, my G35 (short-ram intake) does this at any speed if I give it about 1/2 throttle. Give it only 1/3 or a little more to 2/3 throttle, and it goes away. I've been told that the noise was always there, but the stock intake box and resonators made it less audible. Have you driven another S to compare?
 

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Discussion Starter · #10 ·
I'd be surprised to hear that noise on a stock car. However when intakes do this, it's often not related to rpm at all. Its a factor of airflow passing through the intake valves at a certain rate. For instance, my G35 (short-ram intake) does this at any speed if I give it about 1/2 throttle. Give it only 1/3 or a little more to 2/3 throttle, and it goes away. I've been told that the noise was always there, but the stock intake box and resonators made it less audible. Have you driven another S to compare?
I have driven a 2011 S and don't recall hearing this. However, I never really had the opportunity to flog that one.
 

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Yea that's it! Talk about restriction!!
 

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Does anyone have an update for this one? I have what sounds like the exact same sound. My car isn't an S but does have the sport package/exhaust. Could it be something related to the 'switchable' exhaust??? Like the OP said, it's a very unfortunate distraction which comes in the middle of what would be a great sound and acceleration.
 

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Just a thought, could it be that someone has pulled the vacuum hose from the exhaust valve (to turn Sport mode on always), but forgot to cap the line, so that it is now pulling vacuum?
 

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Just a thought, could it be that someone has pulled the vacuum hose from the exhaust valve (to turn Sport mode on always), but forgot to cap the line, so that it is now pulling vacuum?
I haven't checked on my car but I'll check it out. I don't "think" that's it because the Sports Mode seems to switch on and off with the expected change in exhaust sound and it's a brand new car. It's a really high pitched and intense sound which is why some people suspect a mechanical cause... Thanks for the reply - I'll let everyone know if I learn anything.
 

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More of a squeal like things are rubbing or a a clear tone like someone playing a super high pitched flute? If it's a clear tone, which is what it sounds to me like is being described, I would guess somewhere there is a leak in a seal, could be on the intake side, for example pipe to airbox where at a high rpm there is less resistance in that leak than flowing through the filter. As was mentioned a vacuum line with a leak could do it. Could be post SC- like intake manifold gasket or post combustion in the exhaust path, most likely pre-muffler since you've got more resistance in the cats than the muffler.

Does it make the noise when you rev the engine hard stopped in neutral, or only when you are under load?
 

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I too have a whistle under acceleration. I thought it was intake? But, my exhaust note doesn't change when I hit sport mode. Hmm......
 

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More of a squeal like things are rubbing or a a clear tone like someone playing a super high pitched flute? If it's a clear tone, which is what it sounds to me like is being described, I would guess somewhere there is a leak in a seal, could be on the intake side, for example pipe to airbox where at a high rpm there is less resistance in that leak than flowing through the filter. As was mentioned a vacuum line with a leak could do it. Could be post SC- like intake manifold gasket or post combustion in the exhaust path, most likely pre-muffler since you've got more resistance in the cats than the muffler.

Does it make the noise when you rev the engine hard stopped in neutral, or only when you are under load?
Okay, nice long test drive at lunch on tight, bumpy, country roads and some revs at a standstill. It does NOT make the sound at a standstill. It makes the sound under acceleration whether the radio is on or off and in or out of Sport mode (we had one case of sound coming through the stereo system).

So, I'm really stumped now - this is a base NA car, so not a SC issue. After the nice run I had at lunch I'm almost ready to live with 'some whistling sound under acceleration'. I'd love to know what it is though... As for mechanical or aero I just couldn't say. I would believe either. That fact that it doesn't do it sitting still makes me wonder though. Perhaps I'll try to pay attention to the sound at certain road speeds instead of certain RPMs and see if I notice anything although I belive it happened in every gear at about 5000 RPM. - Thanks for the input.
 

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Yeah my next question was does it happen at a certain speed or RPM. At a speed it's probably aero, at rpm, you still could be looking at a leak in the intake system or vacuum line.

I'll have to take my car out and see if I can make it do it.
 

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I know I revived this horse from the dead, but I do have one more thing to add and then I'm done unless there is some more input (maybe someone from LOTUS!!). I usually noticed this sound under heavy accerleration but I tried it under light throttle but just stayed in gear until it reached 5000RPM which seems to be the point at which it usually kicks in and I still got the sound. So, it doesn't look like it occurs necessarily under heavy or wide open throttle. If I had to guess, I'd say it has something to do with the 'dynamic' valves in the exhaust that allow for Sport mode. Thanks for the replies...
 

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Being a guy who just has to figure things out, this one still has me curious. I've also got the sport pack and the the blue tipped "level 1 sports exhaust" Is that the exhaust you have or do you have the one that comes in the sport pack?

I've not been able to replicate it the problem..yet. I'm going to try what you did and leave it in a lower gear and hit 5000k rpm. I'll let you know what I find.
 
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