Vibration in Track mode PTM active

SpeedFreak14 · 08-29-2022, 01:10 AM

I have ‘17 SS 1LE with about 19k miles. Over the past few months I started using track mode and it’s PTM modes more often for spirited street driving, rather than only using sport mode with competition mode active. I noticed when using track mode, I’d get a vibration throughout the vehicle primarily when transitioning from a medium ‘g’ turn to returning the steering wheel back to center. This vibration was initially just audible, sounded like a stereo bass vibration throughout the interior in about 1 second bursts each time when returning to center on the wheel. It’s been getting worse, more frequent even while turning in higher ‘g’ maneuvers and felt in the steering wheel and pedals. It’s rare in low ‘g’ maneuvers. Weirdly enough, it occurs with track mode only when any PTM mode is active or when traction + stability control are turned off. Doesn’t occur in track mode when only traction control is off or when everything is kept on. Noticeable throughout the vehicle with the radio on or off.

Any ideas what this is? I can upload a YouTube video off the noise if desired. It’s starting to concern me that there’s something worth investigating.

Katech_Zach · 08-29-2022, 08:26 AM

Could be an e-diff or powersteering related issue

Briland_1LE · 08-29-2022, 01:04 PM

Is it the sound of the engine cutting power to manage traction? It does it in a different way when your in the PTM modes and sounds very strange if you don't know what it is.

SpeedFreak14 · 08-29-2022, 09:03 PM

No loss of power, no strange handling inputs, no lost of traction. I haven’t tried it at a super wide range of speeds but I know it happens at least between 35-65mph consistently. Just a vibration in about a 1 second burst. I had the rear diff fluid changed at about 2000 miles. The car gets regular maintenance. I figured it had to be something unique about using PTM, but was surprised when it still did it by just holding the button to disable traction and stability control. But again, doesn’t do it in sport mode PTM, only with track.

I’ll give a look to power steering, but that wouldn’t really explain it being mode specific.

Christian1LE · 08-29-2022, 10:02 PM

Quote:

Originally Posted by SpeedFreak14

No loss of power, no strange handling inputs, no lost of traction. I haven’t tried it at a super wide range of speeds but I know it happens at least between 35-65mph consistently. Just a vibration in about a 1 second burst. I had the rear diff fluid changed at about 2000 miles. The car gets regular maintenance. I figured it had to be something unique about using PTM, but was surprised when it still did it by just holding the button to disable traction and stability control. But again, doesn’t do it in sport mode PTM, only with track.

I’ll give a look to power steering, but that wouldn’t really explain it being mode specific.

Suppose it could if you are using different power steering settings for track and sport.

SpeedFreak14 · 08-29-2022, 11:49 PM

I use tour steering for everything.

Briland_1LE · 08-30-2022, 03:42 PM

Being that it only happens in Track mode is definitely strange. Could it be the MRC dampers?

cdb95z28 · 08-30-2022, 04:47 PM

Do you have PDR?

mano_camaro · 08-30-2022, 07:50 PM

Quote:

Originally Posted by Briland_1LE

Is it the sound of the engine cutting power to manage traction? It does it in a different way when your in the PTM modes and sounds very strange if you don't know what it is.

This is right on the money, if it sounds similar to a tractor trailer engine braking then it is normal when driving in PTM mode.

Try the same road or turns in different modes and it will be a different experience.

PTM "Wet" mode it will happen more often and PTM 3 and race mode will be almost non existent.

Also could be diff fluid need change again or maybe time for elsd module fluid change given the age of the car?

Christian1LE · 08-30-2022, 08:08 PM

He said it happens when he turns everything off though so that can't be right.

SpeedFreak14 · 08-30-2022, 09:30 PM

Quote:

Originally Posted by cdb95z28

Do you have PDR?

Yep, I haven’t tried recording while it happens though.

SpeedFreak14 · 08-30-2022, 09:39 PM

Quote:

Originally Posted by mano_camaro

This is right on the money, if it sounds similar to a tractor trailer engine braking then it is normal when driving in PTM mode.

Try the same road or turns in different modes and it will be a different experience.

PTM "Wet" mode it will happen more often and PTM 3 and race mode will be almost non existent.

Also could be diff fluid need change again or maybe time for elsd module fluid change given the age of the car?

It’s independent of throttle on/off. But it’s not anything cutting power. I’ve felt the ESC cut in and it’s 100% not that. My thought was it has to be something in the dampers or steering, or maybe the e-diff, but I really have no idea how to even pinpoint it without extensive instrumentation.

I supposed a fluid change in the diff wouldn’t hurt.

Little background on me: I’ve worked in automotive test engineering for about 6 years. It’s something I’ve definitely thought about contacting GM to see if they’ve got any ideas but figured I try this forum first. Also there’s no performance mods on the car. Just rockers panels and a wickerbill.

N Camarolina · 08-31-2022, 12:17 AM

Sounds really weird.

I would have guessed it was PTM cutting timing, as that does definitely generate a vibration of sorts, but it's throttle position dependent which the OP has refuted, so I guess that's out.

Also thought it could be ABS related (I've seen ABS activate on track in some unexpected places by looking at the PDR data in PI toolbox), but then presumably that would be PTM mode independent, which also doesn't fit the bill.

E-diff seems like a possible culprit, since it's modes do change with PTM and nannie status.

08-29-2022, 01:10 AM	#1
SpeedFreak14 Drives: 2017 Camaro SS 1LE Join Date: Apr 2017 Location: Nevada Posts: 7	Vibration in Track mode PTM active I have ‘17 SS 1LE with about 19k miles. Over the past few months I started using track mode and it’s PTM modes more often for spirited street driving, rather than only using sport mode with competition mode active. I noticed when using track mode, I’d get a vibration throughout the vehicle primarily when transitioning from a medium ‘g’ turn to returning the steering wheel back to center. This vibration was initially just audible, sounded like a stereo bass vibration throughout the interior in about 1 second bursts each time when returning to center on the wheel. It’s been getting worse, more frequent even while turning in higher ‘g’ maneuvers and felt in the steering wheel and pedals. It’s rare in low ‘g’ maneuvers. Weirdly enough, it occurs with track mode only when any PTM mode is active or when traction + stability control are turned off. Doesn’t occur in track mode when only traction control is off or when everything is kept on. Noticeable throughout the vehicle with the radio on or off. Any ideas what this is? I can upload a YouTube video off the noise if desired. It’s starting to concern me that there’s something worth investigating.

08-30-2022, 04:47 PM	#8
cdb95z28 Drives: 2022 1SS 1LE A10 BCD WCT+PDR Join Date: Mar 2008 Location: Johnstown, PA Posts: 3,203	Do you have PDR? __________________ 2022 1SS 1LE A10 BCD WCT+PDR2014 1SS 1LE NPP RECARO SIM-SOLD1995 Z28 M6 GSC PGM-SOLD1975 NOVA COUPE 300HP 350 TH350 FLASH RED-SOLD

08-29-2022, 08:26 AM	#2
Katech_Zach Drives: 14 Camaro SS 1LE Join Date: Feb 2019 Location: Clinton Twp, MI Posts: 483	Could be an e-diff or powersteering related issue

08-29-2022, 01:04 PM	#3
Briland_1LE Drives: 2020 Camaro SS 1LE Join Date: Apr 2022 Location: Miami Posts: 227	Is it the sound of the engine cutting power to manage traction? It does it in a different way when your in the PTM modes and sounds very strange if you don't know what it is.

08-29-2022, 09:03 PM	#4
SpeedFreak14 Drives: 2017 Camaro SS 1LE Join Date: Apr 2017 Location: Nevada Posts: 7	No loss of power, no strange handling inputs, no lost of traction. I haven’t tried it at a super wide range of speeds but I know it happens at least between 35-65mph consistently. Just a vibration in about a 1 second burst. I had the rear diff fluid changed at about 2000 miles. The car gets regular maintenance. I figured it had to be something unique about using PTM, but was surprised when it still did it by just holding the button to disable traction and stability control. But again, doesn’t do it in sport mode PTM, only with track. I’ll give a look to power steering, but that wouldn’t really explain it being mode specific.

08-29-2022, 11:49 PM	#6
SpeedFreak14 Drives: 2017 Camaro SS 1LE Join Date: Apr 2017 Location: Nevada Posts: 7	I use tour steering for everything.

08-30-2022, 03:42 PM	#7
Briland_1LE Drives: 2020 Camaro SS 1LE Join Date: Apr 2022 Location: Miami Posts: 227	Being that it only happens in Track mode is definitely strange. Could it be the MRC dampers?

08-30-2022, 08:08 PM	#10
Christian1LE Drives: 2004 BMW 330CI, 2022 1SS 1LE Join Date: Dec 2021 Location: NC Posts: 745	He said it happens when he turns everything off though so that can't be right.

08-31-2022, 12:17 AM	#13
N Camarolina Drives: 2021 2SS 1LE Join Date: Aug 2020 Location: Cary, NC Posts: 802	Sounds really weird. I would have guessed it was PTM cutting timing, as that does definitely generate a vibration of sorts, but it's throttle position dependent which the OP has refuted, so I guess that's out. Also thought it could be ABS related (I've seen ABS activate on track in some unexpected places by looking at the PDR data in PI toolbox), but then presumably that would be PTM mode independent, which also doesn't fit the bill. E-diff seems like a possible culprit, since it's modes do change with PTM and nannie status.

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