[Rodan]

IMHO it's a combination of things, but it really comes down to the bushings. The action of the eLSD probably contributes if there's any loss of traction. Soft sidewalls and low tire pressure will increase the amplitude of the oscillation.

If you're going straight, and don't have a loss of traction, you're probably good. Where it's most noticeable is under hard acceleration with a direction change, as in a two-lane passing maneuver. Once the oscillation starts, it either recovers quickly on it's own as the car settles, or it's made worse by the contributing factors of soft sidewalls and/or driver input.

For me, the BMR lockout kit provided a significant improvement. 1LE solid bushings are probably the best fix, but require a lot more work to install.

[kramard]

Originally Posted by Alain

If it’s not traction then I’m gonna go with the way the electronic diff slips the clutches to keep the car going straight or to maintain the line during a turn (if it senses steering input).

I think this is just one of those things that these cars will be known for with no resolution.

I have not read the whole thread but on a road course on cold tires I don't like PTM Sport 1 and 2 and in street driving noticed looseness with any input in sport, track or tour. If I turned all TC SC off (5 second hold of the button) the rear was much more predictable and quieter. Competition mode seemed to be just as good (sport mode, 2 quick presses of the TC button).

Not sure if this helps, but for those struggling curious if the issue exists with TC off as well. Mine is much better now.

[Alain]

Originally Posted by Rodan

IMHO it's a combination of things, but it really comes down to the bushings. The action of the eLSD probably contributes if there's any loss of traction. Soft sidewalls and low tire pressure will increase the amplitude of the oscillation.

If you're going straight, and don't have a loss of traction, you're probably good. Where it's most noticeable is under hard acceleration with a direction change, as in a two-lane passing maneuver. Once the oscillation starts, it either recovers quickly on it's own as the car settles, or it's made worse by the contributing factors of soft sidewalls and/or driver input.

For me, the BMR lockout kit provided a significant improvement. 1LE solid bushings are probably the best fix, but require a lot more work to install.

Mine is a ZL1 1LE and I still feel it so although the solid bushings help, they are not the only contributors. As you mentioned, it’s probably a combination of things.

I’m a believer in the tire / PSI argument. I currently have Michelin’s PSP 4 and feel the wiggle. I wish I would have been able to get on my car while it still had the stock Goodyear’s (which are a header compound and sidewalk). But I was still breaking in the car when I had the Goodyear’s mounted.

Originally Posted by kramard

I have not read the whole thread but on a road course on cold tires I don't like PTM Sport 1 and 2 and in street driving noticed looseness with any input in sport, track or tour. If I turned all TC SC off (5 second hold of the button) the rear was much more predictable and quieter. Competition mode seemed to be just as good (sport mode, 2 quick presses of the TC button).

Not sure if this helps, but for those struggling curious if the issue exists with TC off as well. Mine is much better now.

I’m gonna give this a try next time I take the car out. Gonna try it with less nannies and see what it does.

Thank you for the suggestion.

[bobby35ny]

Wanted to post this while I'm still a little shook up, LOL
I never thought it might be a eLSD issue but I think it is as of 15min ago!
I might start a new thread about it.
Here is my story, I owned the 17 M6 ZL1 new until I traded it in at 12k miles.
Never had the rear sway issue. Never hydroplaned even in the pouring SoFL rains.
I drove cross country with that car with baloney skins to trade it in and it was raining half the trip. I always felt the speed limit was the raining limit, LOL that's how rock solid that car was.

TODAY!!! in my A10.
Driving on the same road I always drive on, Drove on the same road 100 times wet and dry with my M6. NEVER an issue!! Well, I hydroplaned today. it was a holy shit moment for sure. There is something wrong for sure. This car behaves VERY different. They are a ton of A10's out there but only a few of us with this problem.
Car has 2k miles on it and tires are 32PSI all around

[bobby35ny]

Originally Posted by mlee

I really don't think it's traction, but still may be eLSD. My 1st experience was on the drag strip at the 1000' mark with great traction and already rolling at 100mph.

Bushings seem to be a more likely cause.

How could it be the bushings if the ZL1-1LE has the issue to?
Aren't they solid in that car?

[17CamaroZL1]

Originally Posted by 2018ZL1

I run the 17 inch M/T ET Street R's in mine and at the track yesterday it ran a 10.33 at 135 MPH with no movement on the big end... straight as an arrow! I was running 20 pounds of air in the rears. I could have steered it with my knee.. stock stuff under my car.

Were you running front runners too or the stock wheels and tires. I've been told that skinnies up front will help, so I'm curious.

[2018ZL1]

Originally Posted by 17CamaroZL1

Were you running front runners too or the stock wheels and tires. I've been told that skinnies up front will help, so I'm curious.

Skinnies... With all the nannies off as well.

[bobby35ny]

Originally Posted by seanblurr

I wanted to update this with my experiences. Lots of talk about tires and alignment, some claim these caused/fixed the issue while others say this isn't the problem.

Well. I had a KNOWN alignment issue, as in, I had front and rear toe that was fairly out of wack. The car was simply undriveable, the rear end creep was the worst it has ever been. I got my car on an alignment rack, replaced all the bolts, brought the specs back where they should be (1/16th out front, 1/16th in rear toe) and the car is now straight as an arrow.

This entirely unscientific study supports the theory rear-end creep is caused by front and or rear toe being off.

Why did you replace all the bolts?

[17CamaroZL1]

Originally Posted by Rodan

IMHO it's a combination of things, but it really comes down to the bushings. The action of the eLSD probably contributes if there's any loss of traction. Soft sidewalls and low tire pressure will increase the amplitude of the oscillation.

If you're going straight, and don't have a loss of traction, you're probably good. Where it's most noticeable is under hard acceleration with a direction change, as in a two-lane passing maneuver. Once the oscillation starts, it either recovers quickly on it's own as the car settles, or it's made worse by the contributing factors of soft sidewalls and/or driver input.

For me, the BMR lockout kit provided a significant improvement. 1LE solid bushings are probably the best fix, but require a lot more work to install.

What I'm describing and I believe most others that have felt this, is not caused by direction change or loss of traction. I feel it on the dragstrip well passed any speed where you would be losing traction. Its scariest toward the finish as you're traveling 120+. The odd thing is how it occurs. The car is accelerating perfectly fine, then suddenly the rear shifts to one side, causing a bit of steering correction. Sometimes it will hold steady and straight for a second or more with this bit of correction, then it suddenly shifts back to needing a straight wheel, or maybe even needing some wheel in the total opposite direction. I almost never feel this with the stock tires and when I do, it's very faint and really doesn't require any steering correction.

Originally Posted by kramard

I have not read the whole thread but on a road course on cold tires I don't like PTM Sport 1 and 2 and in street driving noticed looseness with any input in sport, track or tour. If I turned all TC SC off (5 second hold of the button) the rear was much more predictable and quieter. Competition mode seemed to be just as good (sport mode, 2 quick presses of the TC button).

Not sure if this helps, but for those struggling curious if the issue exists with TC off as well. Mine is much better now.

I always run with everything off or in Competitive Mode at the strip, so this doesn't help mine.

[17CamaroZL1]

Originally Posted by 2018ZL1

Skinnies... With all the nannies off as well.

So there is hope that front runners might help. Thanks!

[Alain]

Originally Posted by bobby35ny

Wanted to post this while I'm still a little shook up, LOL
I never thought it might be a eLSD issue but I think it is as of 15min ago!
I might start a new thread about it.
Here is my story, I owned the 17 M6 ZL1 new until I traded it in at 12k miles.
Never had the rear sway issue. Never hydroplaned even in the pouring SoFL rains.
I drove cross country with that car with baloney skins to trade it in and it was raining half the trip. I always felt the speed limit was the raining limit, LOL that's how rock solid that car was.

TODAY!!! in my A10.
Driving on the same road I always drive on, Drove on the same road 100 times wet and dry with my M6. NEVER an issue!! Well, I hydroplaned today. it was a holy shit moment for sure. There is something wrong for sure. This car behaves VERY different. They are a ton of A10's out there but only a few of us with this problem.
Car has 2k miles on it and tires are 32PSI all around

I’m glad you were able to save it !!! I had that same thing happen to me exactly a year ago with my first Zl1 1LE. I wasn’t able to save that car, ended up on top of the guardrail.

[seanblurr]

I have a hard time believing it is bushings, if my 1LE has the same problem when the alignment is off.

Originally Posted by bobby35ny

Why did you replace all the bolts?

I replaced them because I've changed alignment quite frequently and after the most recent adjustment the bolts slipped a little. I believe technically they are a TDY bolt anyways.

[bobby35ny]

At this point I HOPE the problem is only a wheel alignment. Here are my base numbers and I think they look pretty bad from the factory. I'm having the dealer line up the car next week.

[BlueinTN]

Originally Posted by bobby35ny

At this point I HOPE the problem is only a wheel alignment. Here are my base numbers and I think they look pretty bad from the factory. I'm having the dealer line up the car next week.

Well what I got from Ted J's long thread was alignments made a CHANGE to how his car handled...even thought in the end it was the tires. So I say alignments has alot to do with how a car behaves.


I really havent made a determination on mine since I am still under 1000 miles. I think it needs more break in time esp the eLSD.