[bjzq8]

I have a 2019 ZL1 auto that has the squirrely-ness problem. The previous owner attempted to fix it by replacing the tires with Nittos all around, but it is still very scary to drive. I had it aligned by a guy who has done race alignments for almost 40 years, and he said he'd never seen a car behave that way in his life, and he's seen a lot. He aligned it to what he thought would help but it is still a dangerous car, even at part throttle. He owns a 427-powered 69 Camaro and he said my ZL1 is the only car he's ever really been afraid of.

I looked over some of the forum posts about this and they all appear to be from 2018 or similar-aged...the only answer I could really get out of it was to replace the rear bushings with solids.

My question is, has anyone else fixed their ZL1's squirrely-ness with something other than bushings or alignment? I'm at a loss as to what could be causing such a terrible condition.

[Z OH 6]

So many things to consider here. I guess the first questions are you sure the tires aren't breaking traction? What are the road conditions? What tires are on the car now and are they all set to correct tire pressure? Was it aligned to factory specs? I think the BMR rear cradle lockout would certainly help but I suspect you've got other issues at play.

[DangerZL1]

You said he aligned it to what he thought would help. Can you post the alignment results before and after? It could also still be related to tires.

[GreenZLE]

Originally Posted by bjzq8

I have a 2019 ZL1 auto that has the squirrely-ness problem. The previous owner attempted to fix it by replacing the tires with Nittos all around, but it is still very scary to drive. I had it aligned by a guy who has done race alignments for almost 40 years, and he said he'd never seen a car behave that way in his life, and he's seen a lot. He aligned it to what he thought would help but it is still a dangerous car, even at part throttle. He owns a 427-powered 69 Camaro and he said my ZL1 is the only car he's ever really been afraid of.

I looked over some of the forum posts about this and they all appear to be from 2018 or similar-aged...the only answer I could really get out of it was to replace the rear bushings with solids.

My question is, has anyone else fixed their ZL1's squirrely-ness with something other than bushings or alignment? I'm at a loss as to what could be causing such a terrible condition.

I'm in Springfield so my car sees the same type of roads yours does. My 2020 ZLE felt like it was going to lose control every time I got on it when it was new. Come to find out, the car would not align to factory specs with the factory rear suspension bars. I ordered all the BMR rear suspension bars and had it aligned and it completely changed the car. It doesnt feel like its getting out of hand now even when its rolling the tires at over 30MPH.

[bjzq8]

Currently it has Nitto NT555G2s on it. All four tires are at 32psi, but I've tried everything from 26 to 40, and variations on the front and back both ways. I don't know what he aligned it to, but he said the rear toe was off quite a bit. He tried changing the alignment several times over the span of a week and nothing seemed to help the condition. If it's breaking loose it's doing so at less than 1/4 throttle. Usually when I pull out to pass someone is when it presents itself most severely; as soon as I put my foot down (less than 1/4 throttle even) it acts like the rear end is very loose. He noted the same condition and suspected maybe it was something with the electronic differential, but to my knowledge, there's no way to fix that, is there? I have tried driving with all of the electronic gewgaws on and with them off; I've tried it in every drive mode and it's just the same.

I'm willing to put new stuff on the back end if it will fix it...can you tell me exactly the BMR parts you put on it?

Thanks for everyone's input! This is definitely the best car I've ever owned, but with one little flaw that might kill me!

[DangerZL1]

Take a look on their site for Bushing kits. It depends on how much NVH you’re willing to tolerate, but the Lockout kit should fix the problem. You could also install the 1LE factory kit, but it’s more work.

I’d do a search and look for posts on this problem. There’s lots of good info in this forum.

[bjzq8]

Thank you, I'll try that.
I've looked all over the site but it seemed like every post was from years ago; I thought maybe I was missing a fix somewhere that everyone had implemented.

I'll report back once I get the bushings installed.

Thank you again for all of the input.

[Z OH 6]

Originally Posted by bjzq8

Thank you, I'll try that.
I've looked all over the site but it seemed like every post was from years ago; I thought maybe I was missing a fix somewhere that everyone had implemented.

I'll report back once I get the bushings installed.

Thank you again for all of the input.

The BMR rear cradle lock out will help and you won't notice any NVH compared to the solid bushings in the 1LE. You get 85-90% of the performance of the solid bushings without sacrificing NVH.

[clg82]

Originally Posted by Z OH 6

The BMR rear cradle lock out will help and you won't notice any NVH compared to the solid bushings in the 1LE. You get 85-90% of the performance of the solid bushings without sacrificing NVH.

^^This, did the whole swap in my garage on jack stands. Completely changed the way the rear felt under load at high speeds.

[GreenZLE]

Originally Posted by bjzq8

Currently it has Nitto NT555G2s on it. All four tires are at 32psi, but I've tried everything from 26 to 40, and variations on the front and back both ways. I don't know what he aligned it to, but he said the rear toe was off quite a bit. He tried changing the alignment several times over the span of a week and nothing seemed to help the condition. If it's breaking loose it's doing so at less than 1/4 throttle. Usually when I pull out to pass someone is when it presents itself most severely; as soon as I put my foot down (less than 1/4 throttle even) it acts like the rear end is very loose. He noted the same condition and suspected maybe it was something with the electronic differential, but to my knowledge, there's no way to fix that, is there? I have tried driving with all of the electronic gewgaws on and with them off; I've tried it in every drive mode and it's just the same.

I'm willing to put new stuff on the back end if it will fix it...can you tell me exactly the BMR parts you put on it?

Thanks for everyone's input! This is definitely the best car I've ever owned, but with one little flaw that might kill me!

I did the on car adjustable control arms, trailing arms, and toe arms. One thing to note though is that the heim joints need to have rubber boots put on them to protect them from dirt or they'll eventually squeak. This happened to mine and I had to replace the ends which I also covered with the boots bought from a large, well known race parts store.

For some people, the poly style bushings might be a better fit but then you dont get the on car adjust ability.

As others suggested, I'd start with the cradle lock out kit on a ZL1. My 1LE already had the solid bushings from the factory so I knew that wasnt my problem. I did drive a regular ZL1 with a 6spd a few months back and immediately noticed how loose the rear cradle felt compared to my car.

[bootss]

My ZLE was scary at full throttle, then I got a good alignment and it just squats and runs. The alignment was all over the place beforehand.
Have it tripple checked.

[Mark114]

Originally Posted by bjzq8

Currently it has Nitto NT555G2s on it.

NT555R2 tires on the rear wheels may give you better traction than the G2s in summer weather.

[WhiteMale]

BMR Cradle lockout, like the others have said, will take out most of that loose feeling on the rear under power. Of course alignment is a thing, tires are a thing, but the cradle lockout is where you're going to find the answer.

[HypeBlueZL1]

Every time I experience the issue you are talking about in my car, I take it in for an alignment. The alignment helps, but I think the lockout kit is the ultimate answer. I intend to get that and install it at some point in the future.