[BMR Suspension]

NVH (noise, vibration, and harshness) is extremely subjective. What is perfectly fine for one person is completely unacceptable to another. That being said we wanted to put together a fairly comprehensive guide to suspension mods and how the performance and NVH will be affected.

Over the course of 2016, BMR Suspension has released a slew of suspension components for the 2016 Camaro. A large portion of this has been mounting solutions for the rear IRS cradle and differential. We are going to touch on each part to give you a better idea of what to expect in the performance and NVH department. This will be a living document that the BMR staff will update on a regular basis. We will add new product benefits and reviews as they come out and encourage you to contribute you opinions so other members can make better-informed decisions on upgrading their suspension. Being that everyone’s idea of what an acceptable level of NVH is is different; we encourage people to post with their opinions. Please list your mods so the information in this thread is as useful as possible.


The Cradle
From the factory, the rear IRS cradle is mounted to the chassis of the car with four very soft rubber bushings. These bushings are great at isolating and absorbing NVH, but there is tremendous deflection when power is applied. When you look at this deflection the cradle is, for all intents and purposes, floating under the car. That means the deflection occurs in fore, aft, lateral, and up and down directions. This is where the “disconnected” feeling comes from under aggressive cornering situations with stock equipment. To take this one step further, the differential and five suspension links on each side of the car are mounted to the cradle. This makes the cradle an extremely integral part of the suspension “system”.

When it comes to upgrading the cradle bushings, BMR has three options—Cradle Bushing Lockout Kit (BK063), Polyurethane Cradle Bushings (BK061), and Delrin Cradle Bushings (BK062).


The Cradle Bushing Lockout Kit is added to the stock cradle bushings. It is designed to limit the fore, aft, lateral, and up and down deflection of the cradle bushings. This kit works with all factory bracing and BMR’s Rear Cradle Braces (CB008 and CB009). This kit is designed for the street performance-based automotive enthusiast who is looking for increased handling without significant increases in NVH. You can expect a slightly firmer feel from the rear suspension, as well as an extremely slight increase in NVH. While this kit does a great job of reducing cradle deflection and improving handling and feel, it may not offer enough deflection reduction for someone with additional horsepower and sticky tires.


The polyurethane replacement bushings are the next step up in performance. These bushings are mounded from 95-durometer polyurethane and do a great job of minimizing deflection, while still absorbing large amounts of NVH. These are a full replacement bushing, meaning the factory cradle bushings need to be removed. The easiest way to remove the factory bushings is to cut them out. This makes the installation of the polyurethane bushings permanent. Polyurethane bushings will tremendously reduce all forms of cradle deflection, dramatically increasing handling and overall driving feel. The polyurethane bushings do a good job of isolating NVH, but some noise may get transmitted through the chassis. These bushings are a great option for performance enthusiasts that regularly use their Camaro on the racetrack or at the autocross.


Delrin replacement cradle bushings are designed for hardcore enthusiasts who want the highest levels of performance. Delrin is a solid polymer that does not deflect. This means more power is transferred and less is absorbed. By eliminating cradle bushing deflection, you get better handling, improved driver feel, and increased throttle response. Unfortunately, by solidly linking the cradle to the chassis, NVH increases can be expected (increases vary depending on how the differential is mounted). By solidly mounting the cradle, alignment changes during aggressive driving is tremendously reduced.


The Differential
The differential in the 2016-newer Camaros is held in place with three super-soft rubber bushings. These do a great job of absorbing NVH, but do nothing for performance. When it comes to mounting the differential, the options are similar to the cradle—polyurethane (BK058 - Coming Soon), billet aluminum (BK059), and a differential lockout kit (BK060).


The cradle lockout kit consists of CNC-machined, billet aluminum inserts that slide into the factory bushings. These fill the voids in the bushings, limiting the deflection, while the factory bushing still absorbs the bulk of the NVH from the differential. By limiting the differential movement, more power is transferred to the tires. This increases throttle response.

*Image Coming Soon*
The polyurethane differential bushings take reducing deflection a step further by replacing the factory bushings. This tremendously reduces bushing deflection, wheelhop, and improving driver feel. Pinion rise is reduced and more power is transferred to the tires. Polyurethane will greatly reduce deflection, but additional NVH can be expected.


Billet aluminum bushings lock the cradle in place, eliminating any movement. This means every bit of power is being transferred, but it also means there is nothing to absorb NVH. These bushings are designed for max-effort street and race applications where noise and NVH is not a concern. These will give you the largest performance benefit, but will also transfer the most noise.


The next wave of products will be focused on max effort handling applications where NVH is not necessarily a concern. We have hinted at spherical bearing replacements for the rear IRS. While these will be available in the very near future, we are also close to releasing spherical bearing replacements for the front suspension. These kits are designed to eliminate bushing deflection, reduce suspension bind, and increase the suspension’s overall effectiveness. This will improve handling and give the driver a much more connected, confident feel over the factory suspension configuration. But the trade-off is increased NVH. As you solidly link the differential, cradle, and suspension links to the chassis, there is less to absorb NVH, so it is transferred through the chassis.

Much much more to come...