Taycan RWD loud whine from drivetrain?

[modernct]

I have a whine noise at low speeds. Is yours similar to this?

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[Marcad80]

The volume can be different car to car based on the alignment of the pinion and ring gear. 20 years ago all hypoid gears were dykemed and ran in to check contact patches between the pinion and the ring gear. If they were off they were adjusted before shipping. I’m sure there’s a more modern way of doing that now. The old General Motors “Detroit Final Drive and Forge”

 

[McgR]

To address a couple of the comments above.

the reason you hear it louder at certain speeds is because as the hypoid gear noise changes frequency with speeds it goes in and out of standing wave dimensions of the cockpit. In our studies it was almost always the length of the rear window to the front window, and a standing wave related to a factor of that distance / frequency.

the noise itself is coming from the sliding action hypoid gears make when interacting, and the frequency Is established from the number of teeth on the pinion and the rpm of the pinion. When an order of this frequency crosses a physical dimension in the cockpit a standing wave is generated and watch out decibels….

i used to set up instrument microphones at the drivers right ear, accelerometers on the suspension, tack light on the drive shaft, and then use an FFT analyzer in a dyno to help develop the GM rear wheel drive cars.

This noise is exactly the same noise we were working to eliminate. And I will tell you Porsche has done a horrible job here. Granted the car is very quite, but 1998 GM cargovans managed gearnoise better than this car.

Does this noise have a constant frequency or is it changing with different speeds ? The noise I hear is always the same. Even with different speeds but disappears with higher speeds but also better roads. Hence I think it is tire noise in my case even though I would expect the sound with be different with different speeds.

 

[Archimedes]

You are correct it was higher frequency sound not a humming. I would classify my electric sport sound as humming but this was much higher frequency.

A bit more like what you can hear in this video. But not at all that much but the pitch was there. But this is more a track car, so it was expected in that case.

The sound of that car is due to it having straight cut gears.

 

[Marcad80]

Does this noise have a constant frequency or is it changing with different speeds ? The noise I hear is always the same. Even with different speeds but disappears with higher speeds but also better roads. Hence I think it is tire noise in my case even though I would expect the sound with be different with different speeds.

the noise has a changing pitch with the rpm of the pinion gear.

the amplitude will go up when frequency is in a dimension of the interior. We used to visualize balls filling the interior. When you hit the ball size that fits evenly you’ve found the wavelength of a standing wave. Then the interior has become a resonance box.

 

[Marcad80]

For those wondering this is the gear noise. It’s loud enough to pick up on a cell phone held by the passenger.

 

[McgR]

For those wondering this is the gear noise. It’s loud enough to pick up on a cell phone held by the passenger.

Thanks for sharing. I have that sound too but I presumed it was the electric engine or pedestrian warning sound. It doesn’t really bother me.

or can we hear two different sounds. I think I have them both.

First full EV I have been in. Never been in a Tesla. Had a X5 40e and 45e before and my wife has a CLA 250e. They all have the electric engine in the gear box and I don’t hear them when driving.

 

[Bennie]

I have a whine noise at low speeds. Is yours similar to this?

My noise is completely different an is a low humming between 50 km/h -70 km/h and around 100 km/h. This high beep is very annoying too ?

 

[Bennie]

For those wondering this is the gear noise. It’s loud enough to pick up on a cell phone held by the passenger.

This sounds completely normal, I would sign for it. Until 50 km/h my car sounds like this too. At around 50 the humming begins. Electric Sport Sound, build in afterwards by the dealer, camouflages it a bit.

 

[f1eng]

For those wondering this is the gear noise. It’s loud enough to pick up on a cell phone held by the passenger.

That is quite poor isn't it.
Mine doesn't do that.
My guess is the tolerance isn't tight enough on CWP alignment so some cars are worse than others.

 

[Scandinavian]

Does this noise have a constant frequency or is it changing with different speeds ? The noise I hear is always the same. Even with different speeds but disappears with higher speeds but also better roads. Hence I think it is tire noise in my case even though I would expect the sound with be different with different speeds.

My observations was that the frequency did change a bit due to speed. More similar to the Mission R sound in the video. As I said it was not tyre noise in my case since it completely disappeared when I put the car into neutral on a downhill trip And just rolled down. Very little Tyre noise due to 19 inch tyres.

 

[Scandinavian]

For those wondering this is the gear noise. It’s loud enough to pick up on a cell phone held by the passenger.

That was exactly the sound I got as well, but it was that sharp tone more than some of the “”humm” that I can hear here. That humm is more like the electric extra sound which I do not like at all.

Always difficult to compare with a recording that picks up all sounds, but for me the sharp high pitched tone was even louder than in your video!

 

[Donlam]

My rwd doesn't have this humm and high pitch noise above 15kph. Below it has little humm noise to my ears. It might happen to yours not me.

 

[McgR]

For those wondering this is the gear noise. It’s loud enough to pick up on a cell phone held by the passenger.

Had a loaner for three days. Same CT 4 with the same 20 inch wheels but Pirelli Cinturato P7 blue Elect tires. Mine has Michelin. The loaner made a very discrete humming noise from 30-35 to 60 kmh. No difference between range normal and sport mode. I could feel the gear shift when switching to sport. So same in first and second gear. However when I got mine back it was now obvious how much sound mine makes when driving these speeds. It is a monotonous humming. Quite irritating and it is not the electric engine. I can also hear that and that changes with different speeds.

the only difference between the two are the tires and mine has rear axl steering.

I does sound more pronounced on bad roads.

should I change my tires to Pirelli ? Ask the dealer to put the wheels of the loaner and see what happens?

retrofit sport sound? The loaner did had sport sound and this could make the noise in mine go more to the background and less obvious.

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