Poor handling after BMR suspension upgrade

[nighttowl]

I had issues with my DSS axles, and had to pull the rear suspension apart again.

The delrin bushed toe arm is just as firm as the day I put it in.
the trailing arms are a different story.

They are worn out.

http://jeffreygoff.com/worn%20bushing.mp4
(right click and save)

I have more of the delrin bushings I made left, I'm going to remove the coil spring and put a set in to make sure there is not any binding, and hopefully use them.

[KaBoom1701]

Bush timing....

[nighttowl]

The only "rubber bushing" that is left on the car is the one in the lower control arm.
polyurethane bushings will rotate all the way around even when tightened, which is the 2nd reason to replace them, with the first being the firmer durometer of materials (less squish).

also, the alignment dude loosened everything up and tightened it down when he aligned it.

one thing I'm not sure of is that the cradle bushings I replaced were way too long and did not fit. my car was an early one (2700's). I'm wondering if there was a change in the cradles design or suspension geometry during production.

here is a video of a bushing.
explain to me the need to time this?

http://jeffreygoff.com/delrin%20bushing.mp4
(right click and save)

also - NICE ZL1

[Bo White]

I have full BMR stuff under the back of mine and no axle hop. It will go to the right when I'm spinning but every other car I've had does that too because of torque and crown of the road.

[nighttowl]

Replacing the poly bushings with delrin in the trailing arms really firmed up the suspension. It handles much better now, it is almost confidence inspiring.

I'm going to look into making delrin bushings form the front lower control arms next.

[gofastwclass]

How is the noise and / or vibration from the back of the car with the Delrin bushings you made?

[2012LS3VERT]

Originally Posted by nighttowl

Replacing the poly bushings with delrin in the trailing arms really firmed up the suspension. It handles much better now, it is almost confidence inspiring.

I'm going to look into making delrin bushings form the front lower control arms next.

It's the front radius rod bushings that need upgrading, the front LCAs are pretty good.
I've done delrin bushings for a couple customers that bought some of my control arms, and have a set in my car, I like it better than the poly bushings. My TransAm has rod ends in the suspension components, so this one is a Cadillac in comparison, lol, even with the aluminum subframe bushings.

[nighttowl]

Originally Posted by gofastwclass

How is the noise and / or vibration from the back of the car with the Delrin bushings you made?

There is not a noticeable difference.

[JusticePete]

I wish I had seen this thread earlier. Those rear sub-frame bushes will be more effective with 3mm of precompression on them. If you are motivated, you could remove the ferules one at a time and cut them down without altering the alignment.

[nighttowl]

Originally Posted by JusticePete

I wish I had seen this thread earlier. Those rear sub-frame bushes will be more effective with 3mm of precompression on them. If you are motivated, you could remove the ferules one at a time and cut them down without altering the alignment.

Is this what you did? there is some compression, but only about 1mm typ.

The back end feels great now, but the front feels sloppy still. I hear a clunk on quick turns sometimes, im wondering if the pillowball mount at the top of the strut is bad. everything is tight, checked 3 times, and inspected for movement.

I read somewhere that there was problems with these cars and the top strut mount wearing out prematurely.
it did not make clunk sounds in the front until I put on the 4 point strut tower brace.
I was also thinking BMR's mounting method using the 4 bolts thru the top of the strut tower was allowing the strut to move more, since is sits in a pocket in the towers, and is technically spaced down due to this. the top of the strut is rubber, but it appeared to me that it did not absorb the bolts fully into the rubber material.

I was thinking about taking the brace off to see if the noise goes away.

the front is next on my list.
delrin radius rod bushings incoming!

[JusticePete]

Originally Posted by nighttowl

Is this what you did? there is some compression, but only about 1mm typ.

The back end feels great now, but the front feels sloppy still. I hear a clunk on quick turns sometimes, im wondering if the pillowball mount at the top of the strut is bad. everything is tight, checked 3 times, and inspected for movement.

I read somewhere that there was problems with these cars and the top strut mount wearing out prematurely.
it did not make clunk sounds in the front until I put on the 4 point strut tower brace.
I was also thinking BMR's mounting method using the 4 bolts thru the top of the strut tower was allowing the strut to move more, since is sits in a pocket in the towers, and is technically spaced down due to this. the top of the strut is rubber, but it appeared to me that it did not absorb the bolts fully into the rubber material.

I was thinking about taking the brace off to see if the noise goes away.

the front is next on my list.
delrin radius rod bushings incoming!

I have some experience with suspension. Based on the durometer of the BMR sub-frame bushing, a 3mm precompression would be in order.

The OE strut mounts are quite robust. I have not seen one worn out.

Eliminating a noise source when chasing a noise is never a bad idea. Give it a shot.

Why not use the Z/28 radius arm with the Delrin insert from the factory?

[nighttowl]

Originally Posted by JusticePete

Why not use the Z/28 radius arm with the Delrin insert from the factory?

I may just do this.