Stabilizing rear end

[cc-rider]

So winter is here and time for some more upgrades. I’d like to know if anyone has done anything to stabilize the rear end “sway” that seems to come in 3rd and 4th gear under hard acceleration? I’ve got about 750 to the wheels now and I’ve snapped the rear end loose with tire spin in 3rd multiple times. But even when it doesn’t snap loose…I feel this sort of back and forth swaying going on. It’s a little unnerving. Speed climbing rapidly and also knowing it could break loose. Just would like to stabilize the rear end some more.

My guess is that this has something to do with the rear cradle and the softer bushings they put in from the factory to control noise. Which…don’t get me wrong…I love the quiet cruise of the Camaro and I don’t want a ton of NVH. But also think I need to get things a bit more under control back there too for safety.

Rear cradle bushings? Control arms? What have people done?

[tartagliazl1]

first what tires do you have? I'm at the same hp level as you and don't break the tires loose. I'm running the Nitto r2 and have the bmr toe rods and trailing arms. I'm also a convertible which has the long braces that connect to the front cradle and the body. I think those bars help a ton with the cradle. With all that said I did order Pedders cradle bushings and front radial arm inserts.

[cc-rider]

I have Nitto tires as well. Can’t recall at the moment exactly which. But they are the 295 or 315 ZL1 width. I also have a ZL1 rear end with 3.73 rear end which is why I think it’s breaking loose. Geared a bit.

[fz4k98]

You should also check the rear alignment for toe and camber. These settings can make a big difference in handling and tire spin.

[acammer]

Originally Posted by cc-rider

So winter is here and time for some more upgrades. I’d like to know if anyone has done anything to stabilize the rear end “sway” that seems to come in 3rd and 4th gear under hard acceleration? I’ve got about 750 to the wheels now and I’ve snapped the rear end loose with tire spin in 3rd multiple times. But even when it doesn’t snap loose…I feel this sort of back and forth swaying going on. It’s a little unnerving. Speed climbing rapidly and also knowing it could break loose. Just would like to stabilize the rear end some more.

My guess is that this has something to do with the rear cradle and the softer bushings they put in from the factory to control noise. Which…don’t get me wrong…I love the quiet cruise of the Camaro and I don’t want a ton of NVH. But also think I need to get things a bit more under control back there too for safety.

Rear cradle bushings? Control arms? What have people done?

Rear subframe bushings need to be the first stop on anyone's journey to improve control of the rear suspension. Until the subframe is held firmly in control, adding things like toe rods and trailing arms does little to solve anything, as the subframe is still free to deflect on the weak factory bushings. And, they deflect a LOT. A poly bushing is an acceptable solution, especially for someone trying to minimize NVH into the car, but with big power and traction even those will still show some deflection, and a solid aluminum bushing is the way to go for optimal control over the rear subframe.

I also have a ZL1 rear end with 3.73 rear end which is why I think it’s breaking loose. Geared a bit.

Which transmission? What sort of power adder? A manual car wouldn't be overgeared at all at your power level with 3.73s, but if it's a 6L80 then that would be quite aggressive (as those have more aggressive ratios in the transmission), especially with a PD blower.

[1JEWLDSSRS]

Here is a video of the rear OEM cradle bushings moving all over the place that acammer was talking about. A lot of us have done this mod including myself, and man what a difference it made in the "solidness of the rear! Got rid of all my wheel hop!

[acammer]

Originally Posted by 1JEWLDSSRS

Here is a video of the rear OEM cradle bushings moving all over the place that acammer was talking about. A lot of us have done this mod including myself, and man what a difference it made in the "solidness of the rear! Got rid of all my wheel hop!

Man, I almost went looking for the link to that. I love that video, because it really shows exactly how extreme the sub-frame deflection is. When I did the sub-frame bushings in my car, I felt the difference the very first time I started to release the clutch backing out of the shop, it was extremely different.

Consider my full weight stick car cuts consistent 1.5x 60' times with no suspension mods other than the sub-frame bushings - I think that says a lot for how important those are, and also how much less important some of those other suspension mods are. I'm not discounting them, and they are on the to-do list, but I haven't found where I see much of a defection or toe issue with the stock stuff once the sub-frame is well controlled.

[SlowLS1]

Originally Posted by 1JEWLDSSRS

Here is a video of the rear OEM cradle bushings moving all over the place that acammer was talking about. A lot of us have done this mod including myself, and man what a difference it made in the "solidness of the rear! Got rid of all my wheel hop!

Cradle bushings in on my todo list this winter. That video should sell anyone who has reservations on the idea of if it's worth it.

[1JEWLDSSRS]

Yes sir guys!!! I did this mod after chatting with Jordan at JDP Motorsports, and if you know them, they track several cars Camaro's and Vettes competitively. They know what is going on!! Like Andrew said, after installing them I noticed a huge difference in how "tight" it was back there when I drove her out of the work bay. Wow. The rest of my suspension is all still stock except for the Pfadt racing springs. With the solid mounts AND the addition of the 1pc aluminum DS, she really puts the power to the wheels now!! And I mean, right now!! One of the best mods I have ever done!

[tartagliazl1]

Then imagine having the bushings plus the convertible brace bars also. lol

[acammer]

Originally Posted by 1JEWLDSSRS

Yes sir guys!!! I did this mod after chatting with Jordan at JDP Motorsports, and if you know them, they track several cars Camaro's and Vettes competitively. They know what is going on!! Like Andrew said, after installing them I noticed a huge difference in how "tight" it was back there when I drove her out of the work bay. Wow. The rest of my suspension is all still stock except for the Pfadt racing springs. With the solid mounts AND the addition of the 1pc aluminum DS, she really puts the power to the wheels now!! And I mean, right now!! One of the best mods I have ever done!

It's funny to think that a subframe bushing would be one of the best mods ever - but I feel the same way. The driveline feel was so awful on this car when it was stock - there are a million joints and places for lash between the crankshaft and the lug-nuts, and slowly I've been picking at getting all of that out of the car. The subframe connectors and 1pc driveshaft were both huge steps forward on that front, and some of my favorite mods, despite being what many would think of as minor changes that do little in terms of power. The feel change, 10/10!

[1JEWLDSSRS]

Originally Posted by acammer

It's funny to think that a subframe bushing would be one of the best mods ever - but I feel the same way. The driveline feel was so awful on this car when it was stock - there are a million joints and places for lash between the crankshaft and the lug-nuts, and slowly I've been picking at getting all of that out of the car. The subframe connectors and 1pc driveshaft were both huge steps forward on that front, and some of my favorite mods, despite being what many would think of as minor changes that do little in terms of power. The feel change, 10/10!

So totally agreed!! I also saw a video on how much the center bearing/bushing moves around on the stock driveshaft and was amazed at that as well. The main reason I went with the 1 pc. I'll have to see if I can find it again.

[cc-rider]

Thanks for the input guys. I definitely need cradle bushings. Will probably go with the poly ones. After watching that video…I’m convinced my cradle is deflating heavily under big pulls.

[Fanch1LE]

Originally Posted by cc-rider

So winter is here and time for some more upgrades. I’d like to know if anyone has done anything to stabilize the rear end “sway” that seems to come in 3rd and 4th gear under hard acceleration? I’ve got about 750 to the wheels now and I’ve snapped the rear end loose with tire spin in 3rd multiple times. But even when it doesn’t snap loose…I feel this sort of back and forth swaying going on. It’s a little unnerving. Speed climbing rapidly and also knowing it could break loose. Just would like to stabilize the rear end some more.

My guess is that this has something to do with the rear cradle and the softer bushings they put in from the factory to control noise. Which…don’t get me wrong…I love the quiet cruise of the Camaro and I don’t want a ton of NVH. But also think I need to get things a bit more under control back there too for safety.

Rear cradle bushings? Control arms? What have people done?

I'm experiencing the same thing, the rear end wanders side to side at WOT, usually begins around 80 mph. It's not tire spin, and it doesn't always begin as soon as I hit the throttle. It's like the torque loads up and then the squirming starts. It's pretty scary. The car tracks straight at any speed when not under hard acceleration. I'm struggling to pinpoint the cause.

Suspension is 1" BMR drop and Bilstein struts, BMR trailing arms, poly diff bushings. Strangely enough this rear end wiggle never happened until I installed BMR rear UCA bushings, UMI adjustable rear toe rods, and BMR delrin rear subframe bushings....all 3 installed at the same time. Alignment was done at that time and tires are good. I did increase rear negative camber from -1 to -1.7 for better handling on the road course. Rear toe is 0 to a tad toed in. Thrust angle 0.01.

I've checked every bolt in the rear and they're tight. I'm scratching my head. If toe is changing dynamically I suspect the UMI toe rods. Could the ferrule be oversized for the bolt? I'm reaching here. I hate to drop $300 on a new set of BMR adjustable rear toe rods just to find out it doesn't help.