Part 2: Deep hum 50-70 km/h and why we should notify Porsche AG

[Bennie]

Recently I posted this thread and promised an update:
https://www.taycanforum.com/forum/threads/deep-hum-between-50-70-km-u-16-23-mph.11825/post-177907

Last week my car was examined by Porsche Netherlands after the dealer tried to synchronize the gearbox. The technician from Porsche Netherlands drove with my car and with two others, all RWD. One of the other cars was also, as is mine, a Sport Tourismo.
The humming appears in first gear at high revs of the electric motor. When driven in ‘range’ mode the humming sound does not occur, because then only the second gear is driven and there is a different gear ratio.

The technician from Porsche Netherlands used the two other cars for a product comparison and noted that they had the same hum in first gear. A three-dimensional scope analysis revealed that they showed a similar image.
His conclusion was that this is a product feature. An electric motor apparently has certain speeds at which you can perceive a hum. My dealer has a report of the analysis (I haven’t seen it yet) and will send it to Porsche AG In Germany. Porsche Netherlands will do the same. The dealer said that when reports from the market are received at Porsche AG, this might be a signal for further action. If and when that will happen, cannot be predicted…

So I’m stuck with the irritating sound and there is certainly not going to be a replacement of the gearbox, like LXA wrote in the first thread. Maybe the warranty in the US is more strictly monitored than in Europe?

My complaint about the humming started after about 6000 km., before that no humming was to be heard. Current mileage is 7000 km. Some of my fellow European Taycan drivers reported in my thread the same problem: McgR, Cyberdriver888, Ambroos.
Uncertain whether the problem affects only RWD Taycans, because the rear engine for all Taycans is the same.
I’ve been looking for sound insulating foam to put in the trunk, but it’s in fact ridiculous even thinking about this. Let Porsche AG solve it.

My call for the European drivers, especially the Netherlands and Belgium: check your car for this sound and the difference with the second gear. If you think your car is infected and you find it as annoying as I do, notify your dealer and through them Porsche AG that they have to solve this problem!

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[Dee]

Has the car the big update already? (colored icons).
This update is supposed to address some (acoustic) issues in the drivetrain as well.

 

[Gru]

I have a similar model (ST RWD): i haven‘t noticed it yet (5000 km only).
I’ll check if if there is a difference between 1st and 2nd (range) gear at these speeds.

 

[Bennie]

Has the car the big update already? (colored icons).
This update is supposed to address some (acoustic) issues in the drivetrain as well.

Thanks Dee, my car had when delivered already the colored icons so a recent software version. Last Monday the car got the big update at the dealer and will be brought back tomorrow. The first thing I’ll do is check whether I notice a difference. I’ll let you know.

 

[XLR82XS]

My drive until was replaced last year and the noise in first gear is still there. Porsche told my dealer it is within spec. It's not right. (2021 RWD) TBD determined what will happen.

 

[Bennie]

My drive until was replaced last year and the noise in first gear is still there. Porsche told my dealer it is within spec. It's not right. (2021 RWD) TBD determined what will happen.

Hi LXA, What a shame to hear that after replacing the drivetrain the problem is back. I wrote in my thread that at least in your case the right solution was made by replacing the drive, and now this.

The technician of Porsche Netherlands also told the dealer that the humming sound in first gear was within the specs. He called it a product feature but I’m starting to believe it is a product error. Certainly in your case where replacing the unit doesn’t solve the problem but repeats it, there is definitely something wrong with the first gear in the Taycans. Porsche AG should take their responsibility.

 

[jvincent]

There were reports of these harmonic rumbles in the Audi e-tron as well. Lower speed range was almost exactly what you are experiencing. It was a polarizing issue with some users bothered and others not. Here's a link to the discussion:

Rear Suspension Noisy?

There's good information and links to technical papers on the subject. Here's an MP3 from the thread where you can hear the noise quite clearly. Is this anything like what you all are experiencing?

body boom boosted

 

[Bennie]

There were reports of these harmonic rumbles in the Audi e-tron as well. Lower speed range was almost exactly what you are experiencing. It was a polarizing issue with some users bothered and others not. Here's a link to the discussion:

Rear Suspension Noisy?

There's good information and links to technical papers on the subject. Here's an MP3 from the thread where you can hear the noise quite clearly. Is this anything like what you all are experiencing?

body boom boosted

Thanks John for your reaction. The sound I hear differs from this. It’s much deeper and much more humming. I’m going to read the Audi comments. But for now, it’s not the suspension that I hear but the gearbox, and more specific the first gear that makes the deep humming sound.

From what I hear until now and from other dealers, some drivers hear it and others don’t. Is it the car that has or doesn’t have the humming sound or are it the more sensitive ears of these drivers?

 

[ElectricSoul]

I can clearly hear some repeating noise on a MY21 CT4. My car is in for the uPdate, so I will give it a try after the update is completed to see if it further reproduces.

In my experience, I have the sound at around 70km/h on a flat surface, but I can not reliably reproduce it on any road.

I'll try to record a video next time it happens, but my hope is that the tuning from the uPdate no longer makes it noticeable.

 

[jvincent]

Thanks John for your reaction. The sound I hear differs from this. It’s much deeper and much more humming. I’m going to read the Audi comments. But for now, it’s not the suspension that I hear but the gearbox, and more specific the first gear that makes the deep humming sound.

From what I hear until now and from other dealers, some drivers hear it and others don’t. Is it the car that has or doesn’t have the humming sound or are it the more sensitive ears of these drivers?

Although the thread title references the rear suspension, I think it is a general motor/body structure resonance that is settled on as the cause. There were some similarities to your situation, so I thought it worth a shot.

In two years with my e-tron, I could identify the sound it if I listened closely, but never found it bothersome. In the case of the Audi, there was a subset of drivers who found it truly annoying.

 

[simcity]

A three-dimensional scope analysis revealed that they showed a similar image.

Is that like a camera pushed inside the drive unit or something else?

 

[W1NGE]

Recently I posted this thread and promised an update:
https://www.taycanforum.com/forum/threads/deep-hum-between-50-70-km-u-16-23-mph.11825/post-177907

Last week my car was examined by Porsche Netherlands after the dealer tried to synchronize the gearbox. The technician from Porsche Netherlands drove with my car and with two others, all RWD. One of the other cars was also, as is mine, a Sport Tourismo.
The humming appears in first gear at high revs of the electric motor. When driven in ‘range’ mode the humming sound does not occur, because then only the second gear is driven and there is a different gear ratio.

The technician from Porsche Netherlands used the two other cars for a product comparison and noted that they had the same hum in first gear. A three-dimensional scope analysis revealed that they showed a similar image.
His conclusion was that this is a product feature. An electric motor apparently has certain speeds at which you can perceive a hum. My dealer has a report of the analysis (I haven’t seen it yet) and will send it to Porsche AG In Germany. Porsche Netherlands will do the same. The dealer said that when reports from the market are received at Porsche AG, this might be a signal for further action. If and when that will happen, cannot be predicted…

So I’m stuck with the irritating sound and there is certainly not going to be a replacement of the gearbox, like LXA wrote in the first thread. Maybe the warranty in the US is more strictly monitored than in Europe?

My complaint about the humming started after about 6000 km., before that no humming was to be heard. Current mileage is 7000 km. Some of my fellow European Taycan drivers reported in my thread the same problem: McgR, Cyberdriver888, Ambroos.
Uncertain whether the problem affects only RWD Taycans, because the rear engine for all Taycans is the same.
I’ve been looking for sound insulating foam to put in the trunk, but it’s in fact ridiculous even thinking about this. Let Porsche AG solve it.

My call for the European drivers, especially the Netherlands and Belgium: check your car for this sound and the difference with the second gear. If you think your car is infected and you find it as annoying as I do, notify your dealer and through them Porsche AG that they have to solve this problem!

For AWD, Range mode uses front motor for drive and engages rear when descending inclines before switching to front. Gearing is on the rear motor only.

 

[Bennie]

Is that like a camera pushed inside the drive unit or something else?

I guess that sensors were placed at several places in the interior of the car. My dealer told me that one sensor was placed on the headrest to measure the sound where you experience it the most. I have no idea how such a 3D analysis looks like, my dealer will show me the next time I visit them.

 

[Bennie]

For AWD, Range mode uses front motor for drive and engages rear when descending inclines before switching to front. Gearing is on the rear motor only.

That’s right Adrian. It’s the same engine as in my RWD, so the disturbing sound at the end of the first gear could be heard too. Does your 4S do this?

 

[W1NGE]

No I don't get this issue (that I've noticed).

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