Supercharger-like whine during back to back accelerations

[Upstate Audi]

I'm taking my car to the dealership in a few weeks to have a few things checked out and one of them is this strange supercharger-like whine that I occasionally hear coming from the engine bay. It only happens once the car is fully warmed up and if I do repeated back to back accelerations. I do have an aftermarket intercooler, intake, and turbo inlet but it also made the sound at the same volume when the car was bone stock. It does not make the sound if I free rev the car in neutral or park.

I'm curious what you guys think. If I take it to the dealership and they say they dont notice it or its nothing should I believe them or should I push to have them investigate it further? Here is a sound clip of what it sounds like. The video doesnt pick it up great but its super noticable in the cabin. Car has 22k miles on it

https://drive.google.com/file/d/17q3...ew?usp=sharing

[oc cc]

Funny you mention this... my car is stock as far as engine goes - no intake, IC, tune, nothing. I am at 10k miles on 2019. My car made this noise day 1 on acceleration. No turbo woosh, no blow-off psss psss, no intake noise, no burbles from the factory, no brrraappp upon deceleration, none of the typical noises associated with a turbo - just the exact same high pitched whine you posted in this video. I legit thought a belt or something was for sure out of place, took it to two different dealers a few months apart and all said it's normal and "I am not sure if you've had a turbo car before but that's the noise it makes" and I'm just like yea lol been around more tuned B8 A4s/S4s than this guy will ever see in his life and I never heard a turbo car sound like this (come to think of it you are right - sounds like a supercharger whine). Just riding out more mileage on this car (about to sell my daily and make this my daily so I can have room for an Emira), so IF something happens I have warranty.

[Upstate Audi]

Funny you mention this... my car is stock as far as engine goes - no intake, IC, tune, nothing. I am at 10k miles on 2019. My car made this noise day 1 on acceleration. No turbo woosh, no blow-off psss psss, no intake noise, no burbles from the factory, no brrraappp upon deceleration, none of the typical noises associated with a turbo - just the exact same high pitched whine you posted in this video. I legit thought a belt or something was for sure out of place, took it to two different dealers a few months apart and all said it's normal and "I am not sure if you've had a turbo car before but that's the noise it makes" and I'm just like yea lol been around more tuned B8 A4s/S4s than this guy will ever see in his life and I never heard a turbo car sound like this (come to think of it you are right - sounds like a supercharger whine). Just riding out more mileage on this car (about to sell my daily and make this my daily so I can have room for an Emira), so IF something happens I have warranty.

Glad to hear someone else has experienced it. Im also not super worried as I also still have warranty but I did buy an EPL tune this month and want to make sure everything is 100% good to go before I potentially TD1 myself.

[brilliant_black]

I remember my 2020 S4 would sometimes do this.

My current 2019 has 40k miles on it and does this, but only on manual downshifts after I’ve done a launch or hard wot acceleration.


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[will13k7]

wtf, sounds like a b8 s4.

[crhh95]

Check the PVC tubes/hoses the plug into the air oil separator and back into the intake. When I had my mishimoto catch Can on the car the hose connections popped off or were loose and when they got loose they would cause the car to make this noise.

Unless it’s fully disconnected it won’t really cause any CEL’s, mine came completely off and it idled rough.

I took the catch can off and replaced with the regular hose and all my problems went away


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[Eric_C]

Mine does it, I thought it was the sport diff because it only happens after a turn on the throttle hard like its taking a bit too long to unwind the rear diff after straightening out.

[Omychron]

AFAIK it's normal when you really push the car. Starts to whine, but only when it's REALLY hot.
Had the same on my TTS before as well, even though it's a completely different engine & turbo. Something typical with the recent VAG turbos?

[KingModest]

AFAIK it is transmission wine, when the oil gets hot there. I have experienced it on stock and tuned car. Everyone should experience this, as it is normal for this car. Just to stay on the safe side, do not push too hard after hearing those sounds.

[Upstate Audi]

AFAIK it is transmission wine, when the oil gets hot there. I have experienced it on stock and tuned car. Everyone should experience this, as it is normal for this car. Just to stay on the safe side, do not push too hard after hearing those sounds.

This actually makes the most sense out of all the other possiblities I've heard here. Especially since it does only seem to happen when I'm super hard on the car. I have however heard it when just putzing around a few times so I'm a little surprised at how easy it is to get the trans oil that hot. I wonder if I can datalog it and see at exactly what temps it starts to become noticable.

[oc cc]

I didn't hear it in the video with the guy who was tracking his S4

And I also hear it when driving normally, not necessarily pushing the car hard.

[brilliant_black]

This actually makes the most sense out of all the other possiblities I've heard here. Especially since it does only seem to happen when I'm super hard on the car. I have however heard it when just putzing around a few times so I'm a little surprised at how easy it is to get the trans oil that hot. I wonder if I can datalog it and see at exactly what temps it starts to become noticable.

I’d think even if you hear that whine it’s still safe right? There is an actual warning in the MMI if the transmissions gets too hot.


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[crhh95]

I have never heard this sound on my 18 except for when I had issues with the catch can. It isn’t supposed to sound like that.

It eventually gave me a CEL once the breather system hose came unconnected enough. If it’s just slightly disconnected it makes this noise and remember there was a TSB for breather hose issues, I would really recommend checking those connections out, not normal.


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[Upstate Audi]

Once again all good points by everyone. For the people saying to check the breather hoses I made sure they are all fully connected. I think there are so many possibilities of what it could be we will have to wait to see what the technician thinks when I bring the car in.

[CELison]

Us b5 owners will tell you that's the turbo lady knocking on your door.

[YoYo]

I will say the only time I have heard anything like that was on a recent B9 YT video. When the video started, I thought why the hell does that B9 sound supercharged? He didn't seem concerned about the sound during his YT vid. That same guy had an updated video recently and he found out he had a bad turbo. I believe it was some bent fins. Maybe I should have mentioned that in my first post, but nobody wants to hear that hah.

[brilliant_black]

I will say the only time I have heard anything like that was on a recent B9 YT video. When the video started, I thought why the hell does that B9 sound supercharged? He didn't seem concerned about the sound during his YT vid. That same guy had an updated video recently and he found out he had a bad turbo. I believe it was some bent fins. Maybe I should have mentioned that in my first post, but nobody wants to hear that hah.

I would here this sometimes on my last S4 which was a brand new 2020 facelift car (RIP) when I’d push it hard back to back, but that was during acceleration.

On my current 2019 B9 at 40k miles,
I’m on E85 stage 2 from 034 making 500hp/600tq and I don’t here it all during acceleration. The only time I here this whine noise is on Downshifts after I do some hard pulls or launches. Other than during this specific situation, I’ve never heard it make this noise.

I can drive a few days not do any pulls and will never hear this noise, but if I do a launch or some hard pulls back to back, I will here this whine on downshifts.

I’d like to think if there was anything actually wrong with my car, something would have given up or let go during a launch, but I clocked my fastest at 3.32 the other day.


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[Upstate Audi]

Us b5 owners will tell you that's the turbo lady knocking on your door.

Thats what im most worried about

I will say the only time I have heard anything like that was on a recent B9 YT video. When the video started, I thought why the hell does that B9 sound supercharged? He didn't seem concerned about the sound during his YT vid. That same guy had an updated video recently and he found out he had a bad turbo. I believe it was some bent fins. Maybe I should have mentioned that in my first post, but nobody wants to hear that hah.

Got a link to the video you mentioned?

[Yeoman]

Its transmission whine.. done it since day one in my RS5 which has the same transmission, so I suspect it's normal. If the sound gets louder I'd consider bringing it in, but not until then. Personally, I love the mechanical sound of the tranny. Catch can's also don't fail driving off the lot.

Turbos make a completely different sound reminiscent of a whistle, not a whine.

[CELison]

Its transmission whine.. done it since day one in my RS5 which has the same transmission, so I suspect it's normal. If the sound gets louder I'd consider bringing it in, but not until then. Personally, I love the mechanical sound of the tranny. Catch can's also don't fail driving off the lot.

Turbos make a completely different sound reminiscent of a whistle, not a whine.

No, they make a whine. Been there several times over the past 13 years.

[Es4Luke]

I have had the same thing happen as well it happens on cruises if im going pretty hard and downshift at high revs sometimes was worried but its random not worried bout it does sound like a b8 s4 supercharger wine for sure


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[Zlatanknowsbest]

Check the bottom of your turbo inlet pipe for the pcv hose. I bet it popped off.


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[NickN]

Glad I’m not the only one hearing this, I was thinking trans too. I’ve had my S4 for almost a month and been stage 1 93 and stage 2 trans tuned (034) for about 3 weeks. I hear it when downshifting after a launch or if I’m driving it hard and it’s already hot.


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[Trentimus]

It’s the transmission.

[YoYo]

[ibis_a3]

Had the same thing happen on my B9 S4 when I drove it hard after multiple back to back runs. Based off the comments from this thread, seems like it's normal.