Rear suspension bushings, etc.

[Casultenbeers]

The diff bushings are a good idea, but solid mounting the rear sub is a big NVH concern. Poly bushings there add a bit of noise with a substantial gain in feel. AL bushings in the subframe will feel good to drive, but it will not be quiet.

Thanks TeeLew for keeping the conversation going. I apologize if the details in my post were unclear. I can elaborate to ensure the OP and anyone interested can discern facts from opinions.

My intent with prefacing my statement with “Personal Opinion” was to clarify that this was not based on personal experience or supporting data. Simply that I have interpreted multiple sources and forum posts in this way. The idea being solid mounting the diff seems be known for extreme NVH and solid mounting the subframe seems to be known for “less” NVH when directly compared to the diff.

To the OP and those interested in changing their bushings I would encourage looking into the shortcomings of installing polyurethane subframe bushings specifically on an S550. Using BMR as an example, BMR themselves have posts online identifying the potential issues and inherent design flaw in their poly subframe bushing option. A quick Google search can get those details.

Now with all of that said, OP did you find a path forward with your build?

If anyone else can provide feedback on diff and subframe bushing installs based on personal experience or supporting data that would be appreciated. Provided that it supports this topic. Thanks.

 

[ChipG]

Hi all,

My suspension has changed a lot since this post. My current setup:

Front:

• Steeda camber plates
• Steeda camber bolts
• Cortex monoball kit (lower control arm bushing)
• BMR springs, sway bar, and end links
• BMR 4-point chassis brace (on backorder)
• BMR front of k-member brace (in garage awaiting install)

Rear:

• SPC camber arms
• BMR camber adjustment lockout kit
• Cortex monoball kit (lower control arm bushing)
• BMR toe links
• BMR vertical links (spherical)
• BMR springs, sway bar, and end links
• BMR IRS subframe support
• BMR cradle bushings (aluminum)
• J&M rear shock mounts

I did have the BMR poly differential bushing lockout kit installed (BMR-BK051) as well but have had that removed. Currently there is increased NVH with this setup - more clunking and squeaking at parking lot speeds, and more road noise while moving, but not what I'd consider an objectionable level. The diff bushings, however, transmitted significant gear whine into the cabin at highway speeds that I found intolerable, which is why those have been removed.

 

[TeeLew]

If anyone can provide feedback on diff and subframe bushing installs based on personal experience or supporting data that would be appreciated. Provided that it supports this topic. Thanks.

That's what I'm doing. I didn't put accelerometers on the chassis to give you a frequency response curve, but I have the BMR Poly subframe bushings and BMR red pucks in the diff. I know what they sound like.

 

[RES_22]

Aluminum diff bushings/inserts generate extreme vibes in everything that isn't nailed down....think cement mixer.

Went back to 90d (black) inserts....very tolerable.